CN114471545B - Noble metal-graphene oxide based composite catalyst and preparation method thereof - Google Patents

Noble metal-graphene oxide based composite catalyst and preparation method thereof Download PDF

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CN114471545B
CN114471545B CN202210301394.9A CN202210301394A CN114471545B CN 114471545 B CN114471545 B CN 114471545B CN 202210301394 A CN202210301394 A CN 202210301394A CN 114471545 B CN114471545 B CN 114471545B
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graphene oxide
noble metal
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composite catalyst
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CN114471545A (en
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黄垒
施利毅
刘懿丹
贾蓉蓉
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University of Shanghai for Science and Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/42—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/48—Silver or gold
    • B01J23/50—Silver
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/48—Silver or gold
    • B01J23/52—Gold
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—
    • B01J35/391—
    • B01J35/393—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
    • B01J37/341—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation
    • B01J37/344—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation of electromagnetic wave energy

Abstract

The invention discloses a noble metal-graphene oxide based composite catalyst and a preparation method thereof, wherein the preparation method adopts a photo-deposition method for controlling the morphology of noble metal, and the noble metal is photo-deposited on reduced graphene oxide to form noble metal nanocrystalline with regular morphology, and the preparation method comprises the following steps: uniformly mixing the nano semiconductor and the graphene oxide solution to obtain a semi-finished product composite base solution; placing the semi-finished product composite base solution into a photoreactor, adding a sacrificial reagent, stirring in the whole process, and introducing gas; irradiating by a controlled light source to obtain a semiconductor-reduced graphene oxide composite base; adding a noble metal precursor solution into the semiconductor-reduced graphene oxide composite base to obtain a semi-finished catalyst; and irradiating the semi-finished catalyst by a controlled light source to obtain the noble metal-graphene oxide based composite catalyst. The composite catalyst has specific crystal face and morphology, is uniformly dispersed, and can be widely applied to the fields of chemical industry, energy sources, environment, biomedicine and the like.

Description

Noble metal-graphene oxide based composite catalyst and preparation method thereof
Technical Field
The invention relates to the technical field of nano functional material preparation, in particular to a preparation method of a noble metal-graphene oxide based composite catalyst with a specific morphology.
Background
Noble metal supported nanocrystals with good morphology control are of great interest because of their broad application prospects. The noble metal carbon-based catalyst represented by gold, silver, platinum and palladium carrying specific crystal faces and morphology is more suitable for the fields of chemical industry, energy sources, environment, sensing, biomedicine and the like compared with the noble metal crystal exposed by the mixed crystal faces due to the outstanding advantages of high stability, high catalytic activity and the like.
In the prior art, a colloid method is often adopted for preparing a noble metal carbon-based composite catalyst, for example, a noble metal/carbon nano composite catalyst disclosed in CN112892528A, and a preparation method and application thereof, wherein the catalyst comprises a carbon matrix and noble metal nano particles combined on the carbon matrix, and the carbon matrix is reduced graphene oxide and/or carbon nano tubes. The preparation method comprises the following steps: 1) Preparing noble metal nano colloid by adopting an alkali-glycol method; 2) Dispersing a carbon material having an oxygen-containing functional group on the surface thereof into water; 3) Mixing and stirring the iridium nano colloid and the obtained carbon material dispersion liquid, and heating; 4) Separating and drying to obtain the noble metal/carbon nano composite catalyst. The method needs to prepare noble metal colloid, has the defects of complex process, difficult control of conditions and the like, and the prepared catalyst is linear and is mainly applied to the fields of water electrolysis and the like.
The prior art semiconductor photo-deposition is a simple and effective method for exciting electrons from a conduction band to a valence band in a simple slurry reactor under the irradiation of ultraviolet or visible light by a semiconductor to respectively generate photo-generated electrons and holes, wherein the photo-generated electrons can reduce a metal precursor on the semiconductor to form metal nano-crystals, the photo-generated holes are captured by a sacrificial reagent such as methanol, and the metal is loaded on the semiconductor by using light source irradiation. The existing photo-deposition technology has the technical difficulties that the nucleation and growth process of the metal nanocrystalline cannot be controlled, so that the prepared noble metal catalyst has the problems of larger particle size, obvious agglomeration phenomenon, low atom utilization rate and the like, and more surfactants, foreign ions or molecules are required to be introduced when the nanocrystalline with the specific morphology is prepared by adopting the conventional technology.
Therefore, it is necessary to research a preparation method capable of precisely controlling nucleation and growth of metal nanocrystals, without introducing more surfactants, foreign ions or molecules, to prepare a noble metal-graphene oxide-based composite catalyst which is uniformly dispersed and has specific crystal planes and morphology.
Disclosure of Invention
The invention aims to provide a preparation method of a noble metal-graphene oxide based composite catalyst, which is characterized in that a photo-deposition method capable of precisely controlling nucleation and growth of metal nanocrystals is adopted to prepare the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology by improving the process and the formula, and meanwhile, the introduction of a surfactant, foreign ions or molecules is avoided, so that the technical problems in the prior art or related technologies are solved.
Another object of an embodiment of the present invention is to provide a noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has a specific crystal plane and morphology.
In order to achieve the above object, the present invention provides a technical solution as follows:
the preparation method of the noble metal-graphene oxide based composite catalyst is characterized in that a method of photo-deposition is adopted to enable the appearance of the noble metal to be controlled, so that noble metal nanocrystals with regular appearance are formed by photo-deposition of the noble metal on reduced graphene oxide, and the preparation method comprises the following steps:
s610: uniformly mixing the nano semiconductor and the graphene oxide solution to obtain a semi-finished product composite base solution;
s620: placing the semi-finished product composite base solution into a photoreactor, adding a sacrificial reagent, stirring in the whole process, and introducing gas;
s630: irradiating by a controlled light source to obtain a semiconductor-reduced graphene oxide composite base;
s640: adding a noble metal precursor solution into the semiconductor-reduced graphene oxide composite base to obtain a semi-finished catalyst;
s650: and irradiating the semi-finished catalyst by a controlled light source to obtain the noble metal-graphene oxide based composite catalyst with regular morphology and exposed specific crystal faces.
The step S610 specifically includes the following steps:
S611: adding the nano semiconductor into the graphene oxide solution, and then performing ultrasonic dispersion for 10-30 min to obtain a mixture of graphene oxide and semiconductor;
s612: and magnetically stirring the mixture at room temperature to obtain a semi-finished product composite base solution. In the step S620, the sacrificial reagent is at least one of methanol and ethanol, and the dosage is 1.0mL to 15.0mL;
the whole stirring is magnetic stirring, and the stirring speed is 1800rpm;
and introducing at least one inert gas of nitrogen and argon into the photoreactor.
The step S630, the controlled light source includes: one of a mercury lamp and a xenon lamp; the irradiation time of the controlled light source is 15min to 30min; the power of the controlled light source is 300W to 1000W.
The nano-semiconductor in the step S640 includes: tiO (titanium dioxide) 2 、ZnO、ZrO 2 、CeO 2 、g-C 3 N 4 At least one of them.
The noble metal precursor solution in step S640 includes: h 2 AuCl 4 Aqueous solution of (a) AgNO 3 Aqueous solution of (H) 2 PtCl 6 Aqueous solutions of PdCl 2 Or Pd (NH) 3 ) 4 Cl 2 Is one of the aqueous solutions of (a).
The mass ratio of the noble metal in the noble metal precursor liquid to the semiconductor-reduced graphene oxide composite base is (3-7) (93-97);
the semiconductor-reduced graphene oxide composite base in the step S640 is prepared from reduced graphene oxide and semiconductor in a mass ratio of (1-7) (1-4).
The noble metal-graphene oxide based composite catalyst is prepared by the method, and noble metal nanocrystals synthesized on reduced graphene oxide through controllable photo-deposition are uniformly dispersed on the reduced graphene oxide and have regular morphology and specific exposed crystal faces.
The noble metal-graphene oxide based composite catalyst has a regular morphology and a specific exposed crystal face, and specifically comprises the following components: pd noble metal nanocrystalline is tetrahedron, hexahedron and decahedron exposing {111} crystal face; the Au noble metal nanocrystalline is tetrahedron, hexahedron and icosahedron exposing {111} crystal face; the Pt noble metal nanocrystalline is exposed as a tetrahedron of a {111} crystal face; ag noble metal nanocrystals are tetrahedrons that expose {111} crystal planes.
Compared with the prior art, the invention at least comprises the following beneficial effects:
1. the preparation method of the noble metal-graphene oxide based composite catalyst provided by the invention simplifies the preparation process and ensures that the process conditions are easy to control by improving the process and the formula and adopting a photo-deposition method capable of precisely controlling the nucleation and the growth of metal nanocrystals. According to the method, the reduced graphene oxide is used as a storage layer for quickly transferring photoelectrons, the situation that the growth process of the photoelectrons is uncontrollable due to quick accumulation of the photoelectrons on noble metals is avoided, components such as an additional surfactant are not needed to be added, the nucleation and the growth process of metal nanocrystals can be effectively controlled, the operation steps are few, the used materials, energy sources and equipment are few, and the cost is saved;
2. The preparation method of the noble metal-graphene oxide based composite catalyst provided by the invention has the advantages that the core steps are few, a semi-finished product composite base solution is obtained by uniformly mixing a nano semiconductor and a graphene oxide solution, the semi-finished product composite base solution is placed in a photoreactor, a sacrificial reagent is added, the whole process is stirred and gas is introduced, the semiconductor-reduced graphene oxide composite base is obtained by irradiation of a controlled light source, a noble metal precursor solution is added into the semiconductor-reduced graphene oxide composite base, the semi-finished product catalyst is obtained, and the semi-finished product catalyst is obtained by irradiation of the controlled light source. In this process, the equilibrium shape of the noble metal nanocrystals is determined by the specific surface free energy of their crystal planes, with the crystal planes with higher surface energies growing faster, thereby forming mixed crystal plane-exposed noble metal crystals. The invention adopts the preparation method, and effectively adjusts the thermodynamic and kinetic crystal growth process through controllable light deposition, which is the key for controlling the shape of the metal nanocrystalline. According to the invention, the reduced graphene oxide is particularly adopted as a storage layer for fast transferring photoelectrons, so that the fast accumulation and growth process of the photoelectrons on noble metals can be effectively controlled; and the size, chemical state and geometric distribution of the noble metal nanocrystalline can be conveniently adjusted by combining the optimized photo-deposition process.
3. The noble metal-graphene oxide based composite catalyst prepared by the invention has the advantages of specific crystal face and morphology, uniform dispersion and the like, can not be agglomerated on a semiconductor, but uniformly grows on reduced graphene oxide with specific morphology, and can be widely applied to the fields of chemical industry, energy sources, environment, sensing, biomedicine and the like.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
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The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 shows a schematic flow chart of a method of preparing a noble metal-graphene oxide-based composite catalyst according to an embodiment of the present invention;
FIG. 2 shows high resolution transmission electron micrographs of the catalysts prepared according to example 1 and comparative example 1 of the present invention, wherein a is the high resolution transmission electron micrograph of the catalyst of example 1, a 1 For the catalyst of example 1, a single morphology high resolution transmission electron microscope plot and a single morphology diffraction plot, b is the catalyst of comparative example 1.
FIG. 3 shows a high resolution transmission electron micrograph of a catalyst prepared according to example 2 of the present invention, wherein a is the high resolution transmission electron micrograph of the catalyst of example 2, a 1 A single morphology high resolution transmission electron microscope plot and a single morphology diffraction plot for the catalyst of example 2;
FIG. 4 shows a high resolution transmission electron micrograph of a catalyst prepared according to example 3 of the present invention, wherein a is the high resolution transmission electron micrograph of the catalyst of example 3, a 1 A single morphology high resolution transmission electron microscope plot and a single morphology diffraction plot for the catalyst of example 3;
FIG. 5 shows high resolution transmission electron micrographs of the catalysts prepared according to example 4 and comparative example 2 of the present invention, wherein a is the high resolution transmission electron micrograph of the catalyst of example 4, a 1 For the catalyst of example 4, a single morphology high resolution transmission electron micrograph, b is the catalyst of comparative example 2.
FIG. 6 shows high resolution transmission electron micrographs of the catalyst prepared according to example 7 and comparative example 3 of the present invention, wherein a is the high resolution transmission electron micrograph of the catalyst of example 7, a 1 High resolution transmission electron microscopy for single morphology of the catalyst of example 7, b is comparative example3.
FIG. 7 shows a high resolution transmission electron micrograph of a noble metal-graphene oxide-based composite catalyst prepared according to example 12 of the present invention, wherein a is a high resolution transmission electron micrograph of the catalyst of example 12, a 1 A single morphology high resolution transmission electron microscopy image of the catalyst of example 12.
Detailed Description
The present invention is described in further detail below with reference to the drawings and examples to enable those skilled in the art to practice the invention by referring to the description.
It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
Unless otherwise specifically indicated, the various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or may be prepared by existing methods.
Example 1:
the preparation method of the noble metal-graphene oxide based composite catalyst provided by the embodiment of the invention adopts a photo-deposition method for controlling the appearance of noble metal, so that the noble metal is photo-deposited on reduced graphene oxide to form noble metal nanocrystalline with regular appearance, and the preparation method comprises the following steps:
s610: uniformly mixing the nano semiconductor and the graphene oxide solution to obtain a semi-finished product composite base solution; the method comprises the following steps:
s611: adding the nano semiconductor into the graphene oxide solution, and then performing ultrasonic dispersion for 10-30 min to obtain a mixture of graphene oxide and semiconductor;
S612: and magnetically stirring the mixture at room temperature to obtain a semi-finished product composite base solution.
In the specific implementation process, after the nano semiconductor is added into the graphene oxide solution, ultrasonic dispersion treatment is carried out, the ultrasonic dispersion time is 10-30 min, a mixture of the graphene oxide and the semiconductor is obtained, the mixture is magnetically stirred at room temperature, a semi-finished product composite base solution is obtained, the nano semiconductor can be uniformly mixed with the graphene oxide through ultrasonic dispersion and magnetic stirring, and nucleation and growth in the subsequent noble metal photochemical deposition process can be more uniform and sufficient.
S620: placing the semi-finished product composite base solution into a photoreactor, adding a sacrificial reagent, magnetically stirring in the whole process, and introducing at least one inert gas in nitrogen and argon, wherein the stirring speed is 1000-3000rpm;
the sacrificial reagent has the function of capturing holes, electrons and holes are generated under the irradiation of a light source respectively in the conduction band and the valence band of the semiconductor oxide in the photo-deposition process, the light source excites the semiconductor, the electrons can reduce a metal precursor on the semiconductor from a ground state to an excited state to form metal nanocrystalline, the left holes have oxidizing property, the electrons and the holes are easy to be combined, and the electrons and the holes are required to be captured by sacrificial reagents such as methanol, ethanol and the like so as to slow down the combination of the electrons and the holes, thereby controlling the reduction degree of the reduced graphene oxide.
The sacrificial reagent is one of methanol and ethanol, and the dosage is 1.0 mL-15.0 mL.
In a specific implementation, one of methanol and ethanol having reducing property may be generally selected as the reducing agent. And the amount of the reducing agent is selected according to the mass of the prepared catalyst, the nano semiconductor and the kind of the noble metal loaded on the reduced graphene oxide, and is 1.0mL to 15.0mL.
The whole magnetic stirring provides a uniform reaction environment, the stirring speed is too high or too low, the reaction is uneven, and the reaction requirement is just met at 1800 rpm.
At least one inert gas such as nitrogen or argon is introduced into the photoreactor, and in a specific implementation, the inert gas such as nitrogen or argon is introduced while the whole process is magnetically stirred, so that the phenomena of reduced catalytic efficiency, low catalyst utilization rate and the like caused by the generation of noble metal oxides or the generation of noble metals in other valence states except zero valence due to the fact that oxygen in the reaction process is fused into a reaction solution are avoided.
S630: irradiating by a controlled light source to obtain a semiconductor-reduced graphene oxide composite base; the controlled light source comprises: one of a mercury lamp and a xenon lamp; the irradiation time of the controlled light source is 15min to 30min; the power of the controlled light source is 300W to 1000W;
In the specific implementation process, the type of a light source is selected according to the types of noble metal ions on the nano semiconductor and the reduced graphene oxide, the light source is one of a mercury lamp and a xenon lamp, the light source is irradiated to a semi-finished product composite base solution of the nano semiconductor and the graphene oxide solution which are uniformly mixed in a photo-reactor, specifically, the light source is added into the photo-reactor, the effect of the light source is to better irradiate light on the semi-finished product composite base solution of the nano semiconductor and the graphene oxide solution which are uniformly mixed, a cold well made of quartz material is used for separating the light source from a reacted solution, the light source with the power of 300W to 1000W is used for irradiating on the semi-finished product composite base solution of the nano semiconductor and the graphene oxide solution which are uniformly mixed in the photo-reactor, and the irradiation duration of the light source is controlled to be 15min to 30min. The semiconductor-reduced graphene oxide composite base is obtained by controlled light source irradiation, and it can be understood that the nano semiconductor reduces graphene oxide into reduced graphene oxide so as to form the semiconductor-reduced graphene oxide composite base, and the purpose is that the reduced graphene oxide is superior to graphene oxide as a storage layer for rapid transfer of photoelectrons, so that the growth process caused by rapid accumulation of photoelectrons on noble metals can be accurately controlled.
S640: adding a noble metal precursor solution into the semiconductor-reduced graphene oxide composite base under the magnetic stirring condition that at least one inert gas of nitrogen and argon and the stirring speed is 1800rpm are introduced into a photoreactor, so as to obtain a semi-finished catalyst;
the above nano-semiconductor includes: tiO (titanium dioxide) 2 (rutile, anatase, P) 25 (rutile anatase mixed crystal)), znO, zrO 2 、CeO 2 、g-C 3 N 4 At least one of them. The carrier is several commonly used semiconductor oxides or nitrides.
The noble metal precursor liquid comprises: h 2 AuCl 4 Aqueous solution of (a) AgNO 3 Aqueous solution of (H) 2 PtCl 6 Aqueous solutions of PdCl 2 、Pd(NH 3 ) 4 Cl 2 One of the aqueous solutions of (a); and selecting an aqueous solution containing the noble metal ions corresponding to the catalyst to be prepared as a noble metal precursor solution.
The mass ratio of the noble metal in the noble metal precursor liquid to the semiconductor-reduced graphene oxide composite base is (3-7) (93-97);
the semiconductor-reduced graphene oxide composite base is prepared from reduced graphene oxide and a semiconductor in a mass ratio of (1-7) (1-4).
S650: and irradiating the semi-finished catalyst by a controlled light source to obtain the noble metal-graphene oxide based composite catalyst with regular shape and specific exposed crystal faces. The method comprises the following steps: the controlled light source is one of a mercury lamp and a xenon lamp; the irradiation time of the controlled light source is 15min to 30min; the power of the controlled light source is 300W to 1000W. And (3) irradiating the semi-finished catalyst through a controlled light source under the magnetic stirring condition that at least one inert gas of nitrogen and argon is introduced into the photoreactor and the stirring speed is 1800rpm, so as to obtain the catalyst. The conduction band and the valence band of the semiconductor respectively generate electrons and holes under the irradiation of ultraviolet or visible light, the light source excites the electrons from a ground state to an excited state, the electrons can reduce the metal precursor on the semiconductor to form metal nanocrystalline, and the remained holes need to be captured by sacrificial reagents such as methanol and the like so as to slow down the recombination time of the electrons and the holes, thereby controlling the nucleation and growth rate of noble metals.
The noble metal-graphene oxide based composite catalyst is prepared by the method, and noble metal nanocrystals synthesized on reduced graphene oxide through controllable photo-deposition are uniformly dispersed on the reduced graphene oxide and have regular morphology and specific exposed crystal faces.
The noble metal-graphene oxide based composite catalyst has a regular morphology and a specific exposed crystal face, and specifically comprises the following components:
pd noble metal nanocrystalline is tetrahedron, hexahedron and decahedron exposing {111} crystal face;
the Au noble metal nanocrystalline is tetrahedron, hexahedron and icosahedron exposing {111} crystal face;
the Pt noble metal nanocrystalline is exposed as a tetrahedron of a {111} crystal face;
ag noble metal nanocrystals are tetrahedrons that expose {111} crystal planes.
The noble metal of the composite catalyst prepared by the method has specific crystal face and morphology, is uniformly dispersed, does not need to add additional surfactant and the like, and can accurately control the nucleation and growth process of the metal nanocrystalline.
The present invention will be described in further detail with reference to the following examples for a clearer understanding of the objects, technical solutions and advantages of the present invention. The specific data set forth in the specific examples described herein are for purposes of illustration only and are not intended to be limiting.
Example 1
The embodiment of the invention specifically provides a noble metal-graphene oxide based composite catalyst TiO based on the embodiment 1 2 -rGO-Pd (tetrahedron) and method for its preparation, the TiO 2 -a process for the preparation of an rGO-Pd (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
will 6.0mg TiO 2 (rutile) and 5.25mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon; by 500W (125 mW/cm) 2 ) After 30min of irradiation, turning off the mercury lamp; pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, and is filtered and dried to obtain the noble metal-graphene oxide based composite catalyst TiO which is uniformly dispersed and has specific crystal face and morphology 2 -rGO-Pd (tetrahedron), stored in a sealed light-tight manner.
Wherein the TiO is 2 The mass ratio of noble metal in rGO-Pd (tetrahedron) and the semiconductor-reduced graphene oxide composite base is 7:93, the mass ratio of reduced graphene oxide and semiconductor contained in the semiconductor-reduced graphene oxide composite base is 7:1, and the consumption of the sacrificial reagent is 15.0mL.
See fig. 2a and 2a 1 The noble metal-graphene oxide based composite catalyst TiO 2 Transmission electron microscopy and high resolution transmission electron microscopy of rGO-Pd (tetrahedron), as can be seen from the transmission electron microscopy of fig. 2 a: regular Pd tetrahedra are uniformly distributed on reduced graphene oxide, as shown in fig. 2a 1 As can be seen in the high resolution transmission electron microscopy image: it has a regular Pd tetrahedron, exposing {111} crystal planes with a 0.225nm interplanar spacing.
Example 2
The embodiment of the invention specifically provides a noble metal-graphene oxide based composite catalyst TiO based on the embodiment 1 2 -rGO-Pd (hexahedron) and method for preparing same, the TiO 2 -rGO-Pd (hexahedral) composite catalyst, comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
9.6mg of TiO 2 (rutile) and 4.8mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of the noble metal in rGO-Pd (hexahedron) to the semiconductor-reduced graphene oxide composite base is 7:93, the mass ratio of the reduced graphene oxide and the semiconductor contained in the semiconductor-reduced graphene oxide composite base is 4:1, and the consumption of the sacrificial reagent is 15.0mL.
See fig. 3a and 3a 1 The noble metal-graphene oxide based composite catalyst TiO 2 Transmission electron microscopy and high resolution transmission electron microscopy of rGO-Pd (hexahedron), as can be seen from the transmission electron microscopy of fig. 3 a: pd hexahedron are uniformly distributed on the reduced graphene oxide, as shown in FIG. 3a 1 As can be seen in the high resolution transmission electron microscopy image: pd hexahedron exposes {111} crystal planes with a 0.225nm interplanar spacing.
Example 3
The embodiment of the invention specifically provides a noble metal-graphene oxide based composite catalyst TiO based on the embodiment 1 2 -rGO-Pd (decahedron) and preparation method thereof, and the TiO 2 -rGO-Pd (decahedron) composite catalyst preparation method, comprising the following steps:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
16.0mg of TiO 2 (rutile) and 4.0mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the method comprises the steps ofThe TiO is 2 The mass ratio of the noble metal in rGO-Pd (hexahedron) to the semiconductor-reduced graphene oxide composite base is 7:93, the mass ratio of the reduced graphene oxide and the semiconductor contained in the semiconductor-reduced graphene oxide composite base is 2:1, and the consumption of the sacrificial reagent is 15.0mL.
See fig. 4a and 4a 1 The noble metal-graphene oxide based composite catalyst TiO 2 Transmission electron microscopy and high resolution transmission electron microscopy of rGO-Pd (decahedron), as can be seen from the transmission electron microscopy of fig. 4 a: pd decahedron is uniformly distributed on the reduced graphene oxide, as shown in FIG. 4a 1 As can be seen in the high resolution transmission electron microscopy image: the Pd decahedron is exposed by {111} crystal planes with a interplanar spacing of 0.225 nm.
Example 4
The embodiment of the invention is based on the embodiment 1, specifically provides TiO 2 -a process for the preparation of an rGO-Pd (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: h 2 AuCl 4 A solution;
3.0mg of TiO 2 (rutile) and 5.63mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 10.0mL of absolute methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. H was added at a concentration of 1.0g/100mL 2 AuCl 4 753. Mu.L of the solution was treated with 500W (125 mW/cm 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of noble metal and semiconductor-reduced graphene oxide composite base in the rGO-Pd (tetrahedron) composite catalyst is 7:93, and the semiconductor-reduced oxidized stoneThe mass ratio of the reduced graphene oxide to the semiconductor contained in the graphene composite base is 15:1, and the consumption of the sacrificial reagent is 10.0mL.
See fig. 5a and 5a 1 The noble metal-graphene oxide based composite catalyst TiO 2 Transmission electron microscopy and high resolution transmission electron microscopy of rGO-Pd (tetrahedron), as can be seen from the transmission electron microscopy of fig. 5 a: au tetrahedra are uniformly distributed on the reduced graphene oxide, as shown in fig. 5a 1 As can be seen in the high resolution transmission electron microscopy image: au tetrahedra are exposed to {111} crystal planes with a 0.235nm interplanar spacing.
Example 5
The embodiment of the invention is based on the embodiment 1, specifically provides TiO 2 -rGO-Pd (hexahedral) composite catalyst, comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: h 2 AuCl 4 A solution;
will 3.8mg TiO 2 (rutile) and 5.53mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 10.0mL of absolute methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. H was added at a concentration of 1.0g/100mL 2 AuCl 4 753. Mu.L of the solution was treated with 500W (125 mW/cm 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of the noble metal and the semiconductor-reduced graphene oxide composite base in the rGO-Pd (hexahedral) composite catalyst is 7:93, the mass ratio of the reduced graphene oxide and the semiconductor contained in the semiconductor-reduced graphene oxide composite base is 12:1, and the consumption of the sacrificial reagent is 10.0mL.
Example 6
The embodiment of the invention is based on the embodiment 1, specifically provides TiO 2 -a process for the preparation of an rGO-Pd (icosahedron) composite catalyst comprising the steps of:
A semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: h 2 AuCl 4 A solution;
will 6.0mg TiO 2 (rutile) and 5.25mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 10.0mL of absolute methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. H was added at a concentration of 1.0g/100mL 2 AuCl 4 753. Mu.L of the solution was treated with 500W (125 mW/cm 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of noble metal and semiconductor-reduced graphene oxide composite base in the rGO-Pd (icosahedron) composite catalyst is 7:93, the mass ratio of reduced graphene oxide and semiconductor contained in the semiconductor-reduced graphene oxide composite base is 7:1, and the consumption of the sacrificial reagent is 10.0mL.
Example 7
The embodiment of the invention is based on the embodiment 1, specifically provides TiO 2 -a process for the preparation of an rGO-Pt (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: h 2 PtCl 6 A solution;
3.0mg of TiO 2 (rutile) and 5.63mL of a graphene oxide solution having a concentration of 8mg/mL were dispersed in a sample bottle containing 260.0mL of ultrapure water, sonicated for 30min, and mixedThe solution was transferred to a photoreactor, 1.0mL of anhydrous methanol was added, after which the whole process was magnetically stirred and purged with argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. H was added at a concentration of 1.0g/100mL 2 PtCl 6 966. Mu.L of the solution was treated with 500W (125 mW/cm 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of the noble metal and the semiconductor-reduced graphene oxide composite base in the rGO-Pt (tetrahedron) composite catalyst is 7:93, the mass ratio of the reduced graphene oxide and the semiconductor contained in the semiconductor-reduced graphene oxide composite base is 15:1, and the consumption of the sacrificial reagent is 1.0mL.
See fig. 6a and 6a 1 The noble metal-graphene oxide based composite catalyst TiO 2 Transmission electron microscopy and high resolution transmission electron microscopy of rGO-Pt (tetrahedron), as can be seen from the transmission electron microscopy of fig. 6 a: pt tetrahedra were uniformly distributed on the reduced graphene oxide, as shown in fig. 5a 1 As can be seen in the high resolution transmission electron microscopy image: pt tetrahedra expose {111} crystal planes with a interplanar spacing of 0.227 nm.
Example 8
The embodiment of the invention is based on the embodiment 1, specifically provides TiO 2 -a process for the preparation of an rGO-Ag (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (rutile) -rGO;
noble metal precursor liquid is selected: agNO 3 A solution;
will be 2.0mg TiO 2 And 5.75mL of graphene oxide solution with the concentration of 8mg/mL is dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 10.0mL of absolute methanol is added, and then the whole process is magnetically stirred and purged by argon. After irradiation with 200W xenon lamp for 30min, the xenon lamp was turned off. Adding 1.0g/100mL of the mixtureAgNO 3 And (5) irradiating 571.2 mu L of the solution for 90min by using a 300W xenon lamp, carrying out suction filtration and drying to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and storing in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of the noble metal and the semiconductor-reduced graphene oxide composite base in the rGO-Ag (tetrahedron) composite catalyst is 7:93, the mass ratio of the reduced graphene oxide and the semiconductor contained in the semiconductor-reduced graphene oxide composite base is 23:1, and the consumption of the sacrificial reagent is 10.0mL.
Example 9
The embodiment of the invention provides a preparation method of a ZnO-rGO-Pd (tetrahedron) composite catalyst on the basis of the embodiment 1, which comprises the following steps:
a semiconductor-reduced graphene oxide composite base carrier is selected: znO-rGO;
noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
6.0mg of ZnO and 5.25mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of absolute methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
The mass ratio of the noble metal in the ZnO-rGO-Pd (tetrahedron) to the semiconductor-reduced graphene oxide composite base is 7:93, the mass ratio of the reduced graphene oxide and the semiconductor contained in the semiconductor-reduced graphene oxide composite base is 7:1, and the consumption of the sacrificial reagent is 15.0mL.
Example 10
The embodiment of the invention is based on the embodiment 1, concretely providesZrO 2 -a process for the preparation of an rGO-Pd (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: zrO (ZrO) 2 -rGO；
Noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
6.0mg of ZrO 2 And 5.25mL of graphene oxide solution with the concentration of 8mg/mL is dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the ZrO 2 The mass ratio of noble metal in rGO-Pd (tetrahedron) and the semiconductor-reduced graphene oxide composite base is 7:93, the mass ratio of reduced graphene oxide and semiconductor contained in the semiconductor-reduced graphene oxide composite base is 7:1, and the consumption of the sacrificial reagent is 15.0mL.
Example 11
The embodiment of the invention specifically provides CeO based on the embodiment 1 2 -a process for the preparation of an rGO-Pd (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: ceO (CeO) 2 -rGO；
Noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
4.0mg CeO 2 And 5.5mL of graphene oxide solution with the concentration of 8mg/mL is dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon. With 500W (125 mW +.cm 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the CeO 2 The mass ratio of noble metal in rGO-Pd (tetrahedron) and the semiconductor-reduced graphene oxide composite base is 7:93, the mass ratio of reduced graphene oxide and semiconductor contained in the semiconductor-reduced graphene oxide composite base is 11:1, and the consumption of the sacrificial reagent is 15.0mL.
Example 12
The embodiment of the invention is based on the embodiment 1, concretely provides g-C 3 N 4 -a process for the preparation of an rGO-Pd (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: g-C 3 N 4 -rGO；
Noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
38.4mg g-C 3 N 4 And 1.2mL of graphene oxide solution with the concentration of 8mg/mL is dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the g-C 3 N 4 -the mass ratio of noble metal in rGO-Pd (tetrahedron) to the semiconductor-reduced graphene oxide composite matrix is 7:93, semiconductorThe mass ratio of the reduced graphene oxide to the semiconductor contained in the reduced graphene oxide composite base is 1:4, and the consumption of the sacrificial reagent is 15.0mL.
See fig. 7a and 7a 1 The noble metal-graphene oxide based composite catalyst g-C 3 N 4 Transmission electron microscopy and high resolution transmission electron microscopy of rGO-Pd (tetrahedron), as can be seen from the transmission electron microscopy of fig. 7 a: regular Pd tetrahedra are uniformly distributed on reduced graphene oxide, as shown in fig. 7a 1 As can be seen in the high resolution transmission electron microscopy image: the regular Pd tetrahedra expose {111} crystal planes with a 0.225nm interplanar spacing.
Example 13
The embodiment of the invention is based on the embodiment 1, specifically provides TiO 2 -a process for the preparation of an rGO-Pd (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (anatase) -rGO;
noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
will 6.0mg TiO 2 (anatase) and 5.25mL of graphene oxide solution with the concentration of 8mg/mL are dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of the noble metal in rGO-Pd (tetrahedron) and the semiconductor-reduced graphene oxide composite matrix is 7:93, and the mass ratio of the reduced graphene oxide and the semiconductor contained in the semiconductor-reduced graphene oxide composite matrix is 71, the consumption of the sacrificial reagent is 15.0mL.
Example 14
The embodiment of the invention is based on the embodiment 1, specifically provides TiO 2 -a process for the preparation of an rGO-Pd (tetrahedral) composite catalyst comprising the steps of:
a semiconductor-reduced graphene oxide composite base carrier is selected: tiO (titanium dioxide) 2 (P 25 )-rGO；
Noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
3.0mg of TiO 2 (P 25 ) And 5.63mL of graphene oxide solution with the concentration of 8mg/mL is dispersed in a sample bottle containing 260.0mL of ultrapure water, ultrasonic treatment is carried out for 30min, the mixed solution is transferred into a photoreactor, 15.0mL of anhydrous methanol is added, and then the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The mercury lamp is irradiated for 60min, filtered, dried to obtain the noble metal-graphene oxide based composite catalyst which is uniformly dispersed and has specific crystal faces and morphology, and the noble metal-graphene oxide based composite catalyst is stored in a sealed and light-proof way.
Wherein the TiO is 2 The mass ratio of noble metal in rGO-Pd (tetrahedron) and the semiconductor-reduced graphene oxide composite base is 7:93, the mass ratio of reduced graphene oxide and semiconductor contained in the semiconductor-reduced graphene oxide composite base is 15:1, and the consumption of the sacrificial reagent is 15.0mL.
Comparative example 1
TiO (titanium dioxide) 2 -a process for the preparation of a Pd composite catalyst comprising the steps of:
the semiconductor carrier is selected as follows: tiO (titanium dioxide) 2 (rutile);
noble metal precursor liquid is selected: pd (NH) 3 ) 4 Cl 2 A solution;
48.0mg of TiO 2 (rutile) was dispersed in a sample bottle containing 260.0mL of ultra pure water, sonicated for 30min, transferred to a photoreactor, and 15.0mL of anhydrous methanol was addedAfter that, the whole process is magnetically stirred and purged by argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. Pd (NH) was added at a concentration of 1.0g/10mL 3 ) 4 Cl 2 91.2. Mu.L of solution with 500W (125 mW/cm) 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The catalyst is irradiated for 60min by a mercury lamp, filtered and dried to obtain the noble metal-graphene oxide based composite catalyst, and the catalyst is stored in a sealed and light-proof way.
Wherein, tiO 2 The mass ratio of noble metal to semiconductor carrier in the Pd composite catalyst is 7:93, and the consumption of the sacrificial reagent is 15.0mL. Referring to fig. 2b, the noble metal-graphene oxide based composite catalyst TiO 2 High resolution transmission electron microscopy of Pd, as can be seen from the transmission electron microscopy of fig. 2 b: irregular Pd is agglomerated on semiconductor TiO 2 And (3) upper part.
Comparative example 2
TiO (titanium dioxide) 2 -Au complex catalyst preparation method comprising the steps of:
the semiconductor carrier is selected as follows: tiO (titanium dioxide) 2 (rutile);
noble metal precursor liquid is selected: h 2 AuCl 4 A solution;
48.0mg of TiO 2 (rutile) was dispersed in a sample bottle containing 260.0mL of ultra-pure water, sonicated for 30min, transferred to a photoreactor, 15.0mL of absolute methanol was added, and then the whole process was magnetically stirred and purged with argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. H was added at a concentration of 1.0g/100mL 2 AuCl 4 753. Mu.L of the solution was treated with 500W (125 mW/cm 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The catalyst is irradiated for 60min by a mercury lamp, filtered and dried to obtain the noble metal-graphene oxide based composite catalyst, and the catalyst is stored in a sealed and light-proof way.
Wherein, tiO 2 The mass ratio of the noble metal and the semiconductor carrier in the Au composite catalyst is 7:93, and the consumption of the sacrificial reagent is 15.0mL. Referring to fig. 5b, the noble metal-graphene oxide based composite catalyst TiO 2 High resolution transmission electron microscopy of Au, as can be seen from the transmission electron microscopy of fig. 5 b: irregular Au is agglomerated onSemiconductor TiO 2 And (3) upper part.
Comparative example 3
TiO (titanium dioxide) 2 -a process for the preparation of a Pt composite catalyst comprising the steps of:
the semiconductor carrier is selected as follows: tiO (titanium dioxide) 2 (rutile);
noble metal precursor liquid is selected: h 2 PtCl 6 A solution;
48.0mg of TiO 2 (rutile) was dispersed in a sample bottle containing 260.0mL of ultra-pure water, sonicated for 30min, transferred to a photoreactor, 15.0mL of absolute methanol was added, and then the whole process was magnetically stirred and purged with argon. By 500W (125 mW/cm) 2 ) After 30min of irradiation of the mercury lamp, the mercury lamp was turned off. H was added at a concentration of 1.0g/100mL 2 PtCl 6 966. Mu.L of the solution was treated with 500W (125 mW/cm 2 ) Is irradiated with a mercury lamp of 1000W (350 mW/cm) 2 ) The catalyst is irradiated for 60min by a mercury lamp, filtered and dried to obtain the noble metal-graphene oxide based composite catalyst, and the catalyst is stored in a sealed and light-proof way.
Wherein, tiO 2 The mass ratio of noble metal to semiconductor carrier in the Pt composite catalyst is 7:93, and the consumption of the sacrificial reagent is 15.0mL. Referring to FIG. 6b, the noble metal-graphene oxide based composite catalyst TiO 2 High resolution transmission electron microscopy of Pt, as can be seen from the transmission electron microscopy of fig. 6 b: irregular Pt agglomerates on semiconductor TiO 2 And (3) upper part.
Comparison test and results thereof
Comparative test was performed on the composite catalysts prepared in comparative example 1 and comparative example 1, and the test results are shown in fig. 2 of high resolution transmission electron microscopy: the test result can also directly show the influence effect of the presence or absence of the reduced graphene oxide on Pd deposition.
As can be seen from the test results of fig. 2: compared with the comparative example 1, the catalyst prepared by the method of the embodiment of the invention has the advantages that Pd is not agglomerated on a semiconductor, but uniformly grown on reduced graphene oxide with a specific morphology; the specific crystal face and the regular morphology of the crystal are as follows: pd noble metal nanocrystalline exposes tetrahedra of {111} crystal faces with a 0.225nm interplanar spacing, while the catalyst prepared in comparative example 1 has uneven Pd distribution and no specific morphology. Comparative test was performed on the composite catalysts prepared in comparative example 4 and comparative example 2, and the test results are shown in high resolution transmission electron microscopy fig. 5: the test result can also directly show the effect of whether the reduced graphene oxide has an influence on gold deposition.
As can be seen from the test results of fig. 5: compared with the comparative example 2, the catalyst prepared by the method of the embodiment of the invention has the advantages that gold does not agglomerate on a semiconductor, but grows on reduced graphene oxide uniformly and with a specific morphology; the specific crystal face and the regular shape of the Au precious metal nanocrystalline are specifically tetrahedrons of {111} crystal faces with 0.235nm of interplanar spacing. Whereas the catalyst prepared in comparative example 2, au has no specific morphology.
Comparative test was performed on the composite catalysts prepared in comparative example 7 and comparative example 3, and the test results are shown in high resolution transmission electron microscopy fig. 6: the test results can also directly show the effect of whether the reduced graphene oxide has an influence on Pt deposition.
As can be seen from the test results of fig. 6: compared with the comparative example 3, the catalyst prepared by the method of the embodiment of the invention does not agglomerate Pt on a semiconductor, but grows on reduced graphene oxide uniformly and with a specific morphology; the specific crystal face and regular plastic appearance of the crystal are as follows: the Pt noble metal nanocrystals exposed tetrahedra of {111} crystal planes with a interplanar spacing of 0.227 nm. The catalyst prepared in comparative example 3 had a non-uniform Pt distribution and no specific morphology.
The preparation method of the noble metal carbon-based composite catalyst with the specific morphology provided by the invention is characterized in that the noble metal nanocrystalline is controlled to carry out the photo-deposition process under the morphology control, so that the noble metal is photo-deposited on the reduced graphene oxide to form a regular morphology. The noble metal of the composite catalyst prepared by the method has specific crystal face and morphology and is uniformly dispersed, the condition that additional surfactant is required to be added is avoided, the nucleation and growth processes of the metal nanocrystalline can be accurately controlled, the operation steps are few, the used materials and equipment are few, and the cost is saved.
It should be noted that, in the ranges of the components, the proportions and the process parameters described in the present invention, other technical schemes obtained by specific selection can achieve the technical effects of the present invention, so they are not listed one by one.
Meanwhile, other technical schemes obtained by adopting other components similar to the semiconductor, the noble metal and the solvent disclosed by the invention are included in the protection scope of the invention.
In the description of the present invention, the terms "one embodiment," "some embodiments," "particular embodiments," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. The preparation method of the noble metal-graphene oxide based composite catalyst is characterized in that a method of photo-deposition is adopted to enable the appearance of the noble metal to be controlled, so that noble metal nanocrystals with regular appearance are formed by photo-deposition of the noble metal on reduced graphene oxide, and the preparation method comprises the following steps:
s610: uniformly mixing the nano semiconductor and the graphene oxide solution to obtain a semi-finished product composite base solution;
s620: placing the semi-finished product composite base solution in a photoreactor, adding a sacrificial reagent, stirring in the whole process, and introducing gas;
s630: irradiating by a controlled light source to obtain a semiconductor-reduced graphene oxide composite base;
s640: adding a noble metal precursor solution into the semiconductor-reduced graphene oxide composite base to obtain a semi-finished catalyst;
s650: irradiating the semi-finished catalyst by a controlled light source to obtain a noble metal-graphene oxide based composite catalyst with regular morphology and specific crystal face exposure;
The noble metal-graphene oxide based composite catalyst has a regular morphology and an exposed crystal face, and specifically comprises the following components: pd noble metal nanocrystalline is tetrahedron, hexahedron and decahedron exposing {111} crystal face; the Au noble metal nanocrystalline is tetrahedron, hexahedron and icosahedron exposing {111} crystal face; the Pt noble metal nanocrystalline is exposed as a tetrahedron of a {111} crystal face; ag noble metal nanocrystals are tetrahedrons that expose {111} crystal planes.
2. The method for preparing a noble metal-graphene oxide based composite catalyst according to claim 1, wherein the step S610 specifically comprises the following steps:
s611: adding the nano semiconductor into the graphene oxide solution, and then performing ultrasonic dispersion for 10-30 min to obtain a mixture of graphene oxide and semiconductor;
s612: and magnetically stirring the mixture at room temperature to obtain a semi-finished product composite base solution.
3. The method for preparing a noble metal-graphene oxide-based composite catalyst according to claim 1, wherein in the step S620, the sacrificial reagent is at least one of methanol, ethanol and lactic acid, and the amount is 1.0 mL to 15.0 mL;
the whole stirring is magnetic stirring, and the stirring speed is 1000-3000 rpm;
And introducing at least one inert gas of nitrogen and argon into the photoreactor.
4. The method for preparing a noble metal-graphene oxide-based composite catalyst according to claim 1, wherein the step S630, the controlled light source thereof comprises: one of a mercury lamp and a xenon lamp; the irradiation time of the controlled light source is 15 min to 30 min; the power of the controlled light source is 300W to 1000W.
5. The method for preparing the noble metal-graphene oxide-based composite catalyst according to claim 1, wherein:
the nano-semiconductor includes: tiO (titanium dioxide) 2 、ZnO、ZrO 2 、CeO 2 、g-C 3 N 4 At least one of them.
6. The method for preparing the noble metal-graphene oxide-based composite catalyst according to claim 1, wherein:
the noble metal precursor solution in step S640 includes: h 2 AuCl 4 Aqueous solution of (a) AgNO 3 Aqueous solution of (H) 2 PtCl 6 Aqueous solutions of PdCl 2 Or Pd (NH) 3 ) 4 Cl 2 One of the aqueous solutions of (a);
the mass ratio of the noble metal in the noble metal precursor liquid to the semiconductor-reduced graphene oxide composite base is (3-20) (93-97).
7. The method for preparing the noble metal-graphene oxide-based composite catalyst according to claim 1, wherein:
the semiconductor-reduced graphene oxide composite base in the step S640 is prepared from reduced graphene oxide and a semiconductor in a mass ratio of (1-7) (1-4).
8. A noble metal-graphene oxide based composite catalyst is characterized in that: which is prepared by the method of any one of claims 1 to 7, precious metal nanocrystals synthesized on reduced graphene oxide via controlled photo-deposition, which are uniformly dispersed on reduced graphene oxide and have a regular morphology and exposed crystal planes.
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