CN107096532B - Au-ZrO 2 catalyst and application thereof - Google Patents

Au-ZrO 2 catalyst and application thereof Download PDF

Info

Publication number
CN107096532B
CN107096532B CN201710344789.6A CN201710344789A CN107096532B CN 107096532 B CN107096532 B CN 107096532B CN 201710344789 A CN201710344789 A CN 201710344789A CN 107096532 B CN107096532 B CN 107096532B
Authority
CN
China
Prior art keywords
zro
modified
catalyst
carrier
hydrogen
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201710344789.6A
Other languages
Chinese (zh)
Other versions
CN107096532A (en
Inventor
宋利
李雷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiaxing University
Original Assignee
Jiaxing University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiaxing University filed Critical Jiaxing University
Priority to CN201710344789.6A priority Critical patent/CN107096532B/en
Publication of CN107096532A publication Critical patent/CN107096532A/en
Application granted granted Critical
Publication of CN107096532B publication Critical patent/CN107096532B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/61—Surface area
    • B01J35/613—10-100 m2/g
    • 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
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/64—Pore diameter
    • B01J35/647—2-50 nm
    • 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
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/64—Pore diameter
    • B01J35/651—50-500 nm
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/06—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents
    • C01B3/12—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide
    • C01B3/16—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide using catalysts
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Inorganic Chemistry (AREA)
  • Catalysts (AREA)

Abstract

The invention discloses a modified Au-ZrO 2 catalyst and application thereof, wherein the modified Au-ZrO 2 catalyst comprises a carrier and an active component, wherein the carrier is obtained by roasting and modifying double-mesoporous ZrO 2 in a hydrogen atmosphere, ZrO 2 prepared by a hydrothermal method is placed in the hydrogen atmosphere to be roasted to obtain a modified carrier, and then gold is loaded, so that the specific surface area of the obtained modified catalyst is improved, the average pore diameter is reduced, the surface oxygen vacancy is obviously increased, the loaded gold exists in a zero valence state Au (non-oxidation state), the electron-hole recombination is inhibited, the density of a donor is increased, and the charge transmission efficiency is improved, so that the catalytic activity of the catalyst is obviously improved, and the conversion rate of CO in a water gas shift reaction is improved.

Description

Au-ZrO 2 catalyst and application thereof
Technical Field
The invention relates to the field of catalyst preparation, and particularly relates to an Au-ZrO 2 catalyst and application thereof.
Background
The water gas reaction (WGS) also eliminates carbon monoxide while obtaining clean hydrogen. In recent years, the rising of proton exchange membrane fuel cell technology using pure hydrogen as fuel has made the original traditional shift catalyst unable to meet the requirements of fuel cell system. Therefore, it is of great importance to develop new shift catalysts with high activity and stability.
In the eighties of the last century, Haeuta in Japan found that a gold catalyst loaded on a transition metal oxide has high catalytic activity for low-temperature oxidation of CO, and a supported Au catalyst has high low-temperature activity, a wide activity temperature range, good oxidation resistance and water resistance, so that the supported Au catalyst is considered to be one of WGS catalysts which are most suitable for the severe operating environment of PEMFC.
ZrO 2 has acid-base property, oxidation-reduction property, good thermal stability and mechanical strength, and is increasingly paid attention to and widely applied to research as a catalyst carrier.
For example, the invention patent application with the application publication number of CN102389795A discloses a nano gold catalyst for hydrogen production by formic acid decomposition and a preparation method thereof, the catalyst consists of a carrier and an active component, wherein the carrier is ZrO 2 or TiO 2, the active component is nano-sized metallic gold, the mass content of the gold is 0.45-5%, and the gold is respectively marked as Au/ZrO 2 and Au/TiO 2.
Among them, the Au-ZrO 2 catalyst has also been reported to have a very high WGS activity.
The invention patent application with application publication number CN101954279A discloses a low-temperature water gas shift catalyst applied to hydrogen-rich reformed gas and a preparation method thereof, the catalyst comprises Au/ZrO 2, wherein an active component is Au, a carrier is ZrO 2, the weight content of Au is 0.1-3%, and the weight content of ZrO 2 is 97-99.9%.
Disclosure of Invention
The invention provides a modified Au-ZrO 2 catalyst and application thereof in preparation of hydrogen through water gas shift reaction, wherein the modified Au-ZrO 2 catalyst has high catalytic activity.
The modified Au-ZrO 2 catalyst comprises a carrier and an active component, wherein the carrier is obtained by roasting and modifying ZrO 2 in a hydrogen atmosphere.
The ZrO 2 is prepared by a hydrothermal method, and specifically comprises the steps of carrying out hydrothermal reaction on ZrOCl 2.8H 2 O at 150 ℃ for 6 hours, washing and drying to obtain ZrO 2.
the research shows that the catalytic activity of the catalyst can be effectively improved by processing ZrO 2 in the hydrogen atmosphere, and the comprehensive characterization result shows that the activity of the modified Au-ZrO 2 catalyst is closely related to the specific surface area, the pore volume, the grain size of a ZrO 2 carrier, the surface oxygen vacancy and the like.
Therefore, for the modified Au-ZrO 2 catalyst, the active component is simple gold.
Furthermore, the carrier is double-mesoporous ZrO 2 and comprises 3-6 nm mesopores and 30-40 nm stacking holes, so that the specific surface area of the carrier and the catalyst is improved, and the activity of the catalyst taking hydrogen-calcined ZrO 2 as the carrier is improved.
Further, the roasting conditions of the carrier are as follows: roasting at 500-600 ℃ under normal pressure for 2-6 h, or roasting at 200-300 ℃ under 10-20 atm for 2-4 h.
Furthermore, the specific surface area of the modified Au-ZrO 2 catalyst is 20-30 m 2/g, and the average pore radius is 20-40 nm.
Further, the electron density of the modified ZrO 2 carrier and the electron density of the modified Au-ZrO 2 catalyst are respectively 1 × 10 23 -9 × 10 23 cm -3 and 1 × 10 24 -9 × 10 24 cm -3.
The invention also provides application of the modified Au-ZrO 2 catalyst in preparation of hydrogen through water gas shift reaction.
The invention provides a method for preparing hydrogen by performing water gas shift reaction by using a modified Au-ZrO 2 catalyst, wherein the reaction temperature is 200-600 ℃.
In a water gas shift reaction system, the ratio of water vapor to feed gas is kept at 0.5: 1-1: 1, the volume concentration of CO in the feed gas is 1-15%, the volume concentration of H 2 is 0-50%, and the volume concentration of CO 2 is 0-12%.
Compared with the prior art, the invention has the following beneficial effects:
According to the invention, ZrO 2 prepared by a hydrothermal method is placed in a hydrogen atmosphere to be roasted to obtain a modified carrier, and then gold is loaded, so that the specific surface area of the obtained modified catalyst is increased, the average pore diameter is reduced, the surface oxygen vacancy is obviously increased, the loaded gold exists in a zero-valence Au (non-oxidation state) form, the electron-hole recombination is inhibited, the density of a donor is increased, and the charge transmission efficiency is improved, so that the catalytic activity of the catalyst is obviously improved, and the conversion rate of CO in the water gas shift reaction is improved.
Drawings
FIG. 1 shows the results of the WGS reaction catalytic activities of the modified Au-ZrO 2 catalysts prepared in example 1 and comparative examples 1 to 7.
FIG. 2 is an XRD pattern of a modified ZrO 2 support and a modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2;
Wherein a is Au-ZrO 2 -HT-A, b is ZrO 2 -HT-A, c is Au-ZrO 2 -HT-H, d is ZrO 2 -HT-H, e is Au-ZrO 2 -HT-A-H, and f is ZrO 2 -HT-A-H.
FIG. 3 is the SEM photograph results of the modified Au-ZrO 2 catalysts prepared in example 1 and comparative example 1;
Wherein a is Au-ZrO 2 -HT-A, and b is Au-ZrO 2 -HT-H.
FIG. 4 is a TEM image and an HRTEM (broken line is an interface of a disordered layer and a crystalline core) image of the modified ZrO 2 support and the modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2;
Wherein a, b and g are sequentially TEM images of Au-ZrO 2 -HT-H, Au-ZrO 2 -HT-A-H and Au-ZrO 2 -HT-A, and c, e, H, d, f and i are sequentially HRTEM images of ZrO 2 -HT-H, ZrO 2 -HT-A-H, ZrO 2 -HT-A, Au-ZrO 2 -HT-H, Au-ZrO 2 -HT-A-H and Au-ZrO 2 -HT-A.
FIG. 5 is a plot of the N 2 desorption/adsorption of the modified ZrO 2 support and the modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2.
FIG. 6 is a graph of the pore size distribution of the modified ZrO 2 support and the modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2.
FIG. 7 is an XPS spectrum of the modified ZrO 2 support and the modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2.
FIG. 8 is an EPR spectrum of the modified ZrO 2 support and the modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2.
FIG. 9 is a graph showing fluorescence spectra of the modified ZrO 2 support and the modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2.
FIG. 10 is a Mott-Schottky plot of the modified ZrO 2 support and modified Au-ZrO 2 catalyst prepared in example 1 and comparative examples 1 and 2.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the present invention is not limited thereto. The measurement methods not described in detail in the present invention are all conventional in the art.
The main instruments adopted in the embodiment of the invention are as follows: x-ray powder diffractometers (X' pertpro) available from Panalytic, Netherlands; raman spectroscopy (Renishaw inviia Plus) was purchased from renisha, uk; specific surface tester (Micrometrics ASAP 2020) available from U.S. microphone; x-ray photoelectron spectrometer (VG ESCALB 250) was purchased from U.S. thermal electric company; high resolution transmission electron microscopes (JEOL 2010F (200kV)) are available from JEOL corporation of japan; a field emission scanning electron microscope (Hitachi S-4800) was purchased from Hitachi, Japan; electron paramagnetic resonance apparatus (Bruker EMX-8) available from Bruker, Germany; a fluorescence spectrometer (Hitachi F-4500) is available from Hitachi, Japan; electrochemical workstation (CHI660D) was purchased from shanghai chenhua instruments ltd; the gas-solid phase catalytic reaction device is purchased from Tianjin Tianda North ocean company.
The main reagents used in the examples of the present invention: zirconium oxychloride octahydrate, sodium hydroxide, ammonia water and chloroauric acid are purchased from chemical reagents of national medicine group, Inc.; pure hydrogen, pure nitrogen and high purity carbon monoxide were purchased from Conlong medical gas Co.
Characterization of each index:
(1) X-ray powder diffraction (XRD): the bulk mechanism, the crystalline phase composition and the microstructure of the catalyst or the carrier are carried out on an X 'pertpro diffractometer of the Panalytic company in the Netherlands, an X' Celerator detector is adopted, Cu-Ka (lambda is 0.1541nm) target radiation is carried out, the tube voltage is 40kV, the tube current is 40mA, the scanning step length is 0.12 degree/min, and the scanning range is 10 degrees to 140 degrees. (2) Raman spectroscopic characterization (Raman): the instrument was Renishaw inviia Plus, and raman spectra were collected at room temperature using a semiconductor laser as the illumination source (wavelength 532 nm).
(3) X-ray photoelectron spectroscopy (XPS): on a VG ESCALB model 250 (thermo electric company, USA) photoelectron spectrometer; all electron Binding Energies (BEs) were calibrated with C1 s (284.5eV) as an internal standard.
(4) Specific surface area characterization (BET): performed on a Micrometrics ASAP 2020 instrument; the specific surface area, pore volume and pore size distribution of the sample were measured by using nitrogen as the adsorption gas.
(5) High Resolution Transmission Electron Microscopy (HRTEM): the morphology of the sample was observed using a JEOL 2010F (200kV) type field emission high resolution transmission electron microscope. And grinding a catalyst sample, dissolving the ground catalyst sample in ethanol, performing ultrasonic oscillation for 20min, dripping the upper suspension into a carbon-coated copper net, naturally airing, and observing the particle morphology and the crystallization degree under a 200kV electron beam.
(6) Field emission Scanning Electron Microscope (SEM): the morphology was observed using a Hitachi S-4800 field emission scanning electron microscope.
(7) Electron Paramagnetic Resonance (EPR): electron Paramagnetic Resonance (EPR) spectra were collected at 9.44GHz using a Bruker EMX-8 spectrometer at room temperature.
(8) Fluorescence spectrometer (PL): the measurement was carried out by using Hitachi F-4500 fluorescence spectrometer with an excitation light source of 300 nm.
(9) Mott-Schottky curves (Mott-Schottky plots): electrochemical impedance measurements were performed in the dark at a frequency of 10kHz using the CHI660D electrochemical workstation. The electrolyte is 1M sodium hydroxide solution (pH is 13.6), and the saturated calomel electrode and the platinum electrode are respectively a reference electrode and a counter electrode.
Example 1 preparation of modified ZrO 2 Carrier (ZrO 2 -HT-H) and modified Au-ZrO 2 catalyst (Au-ZrO 2 -HT-H)
Preparation of modified ZrO 2 carrier
The preparation process comprises the following steps:
(1) Preparing ZrO 2 carrier by a hydrothermal method (HT), namely filling 60mL of 0.40mol/L ZrOCl 2 & 8H 2 O aqueous solution into a 100mL polytetrafluoroethylene pot, putting the polytetrafluoroethylene pot into a stainless steel high-pressure reaction kettle, screwing, carrying out hydrothermal reaction for 6 hours at 150 ℃, then carrying out high-speed centrifugal washing on the hydrothermal product for a plurality of times until the pH value of a supernatant is neutral, and drying the obtained precipitate at 70 ℃ overnight to obtain the ZrO 2 carrier.
(2) The ZrO 2 carrier was calcined at 550 ℃ for 4 hours in a hydrogen (H) atmosphere to obtain a modified ZrO 2 carrier (abbreviated as: ZrO 2 -HT-H).
Di, modified Au-ZrO 2 catalyst
Au-ZrO 2 catalyst (Au-ZrO 2 -HT-H) containing 4 wt.% Au was prepared by co-current co-precipitation using the above-described modified ZrO 2 carrier (ZrO 2 -HT-H).
The specific method comprises the following steps:
(1) adding 0.7g of the modified ZrO 2 carrier into 200mL of deionized water, adjusting the pH to 8 +/-1, and taking the obtained solution as a base solution;
(2) Adding 0.4mL of 27 wt.% ammonia water into 100mL of deionized water to obtain a solution C, and adding 60mL of 0.0025 mol/L HAuCl 4 solution to obtain a solution D;
(3) Simultaneously dropwise adding the solution C and the solution D into the base solution through a peristaltic pump, strongly stirring, and keeping the reaction temperature at 80 ℃ and the pH value at 8 +/-1;
(4) After the dropwise addition is finished, the mixture is continuously aged for 6 hours at the temperature of 80 ℃, and the obtained precipitate is filtered, washed for several times to remove impurity ions, and then dried overnight at the temperature of 70 ℃ to prepare the modified Au-ZrO 2 catalyst.
Comparative mut mutexample 1 preparation of modified ZrO 2 Carrier (ZrO 2 -HT-A) and modified Au-ZrO 2 catalyst (Au-ZrO 2 -HT-A)
Preparation of modified ZrO 2 carrier
The preparation process comprises the following steps:
(1) Preparing ZrO 2 carrier by a hydrothermal method (HT), namely filling 60mL of 0.40mol/L ZrOCl 2 & 8H 2 O aqueous solution into a 100mL polytetrafluoroethylene pot, putting the polytetrafluoroethylene pot into a stainless steel high-pressure reaction kettle, screwing, carrying out hydrothermal reaction for 6 hours at 150 ℃, then carrying out high-speed centrifugal washing on the hydrothermal product for a plurality of times until the pH value of a supernatant is neutral, and drying the obtained precipitate at 70 ℃ overnight to obtain the ZrO 2 carrier.
(2) The ZrO 2 carrier was calcined at 550 ℃ for 4 hours in a static air (A) atmosphere to obtain a modified ZrO 2 carrier (abbreviated as: ZrO 2 -HT-A).
di, modified Au-ZrO 2 catalyst
The specific preparation method is the same as that of example 1.
Comparative mut mutexample 2 preparation of modified ZrO 2 Carrier (ZrO 2 -HT-A-H) and modified Au-ZrO 2 catalyst (Au-ZrO 2 -HT-A-H)
preparation of modified ZrO 2 carrier
The preparation process comprises the following steps:
(1) Preparing ZrO 2 carrier by a hydrothermal method (HT), namely filling 60mL of 0.40mol/L ZrOCl 2 & 8H 2 O aqueous solution into a 100mL polytetrafluoroethylene pot, putting the polytetrafluoroethylene pot into a stainless steel high-pressure reaction kettle, screwing, carrying out hydrothermal reaction for 6 hours at 150 ℃, then carrying out high-speed centrifugal washing on the hydrothermal product for a plurality of times until the pH value of a supernatant is neutral, and drying the obtained precipitate at 70 ℃ overnight to obtain the ZrO 2 carrier.
(2) The ZrO 2 carrier was calcined at 550 ℃ for 4 hours in a static air (A) atmosphere and then at 550 ℃ for 4 hours in a hydrogen (H) atmosphere to obtain a modified ZrO 2 carrier (abbreviated as: ZrO 2 -HT-A-H).
Di, modified Au-ZrO 2 catalyst
The specific preparation method is the same as that of example 1.
COMPARATIVE EXAMPLE 3 preparation of modified ZrO 2 Carrier (ZrO 2 -P-H) and modified Au-ZrO 2 catalyst (Au-ZrO 2 -P-H)
Preparation of modified ZrO 2 carrier
The preparation process comprises the following steps:
(1) Preparing zirconium dioxide by adopting a precipitation method (P), namely weighing 4.51g of ZrOCl 2 & 8H 2 O (AR, national drug group chemical reagent Co., Ltd.) into 70mL of water, uniformly stirring, marking as solution A, preparing 200mL of 0.5mol/L NaOH solution, marking as solution B, simultaneously dropwise adding the solution A and the solution B into 200mL of distilled water by a peristaltic pump, intensively stirring, keeping the reaction temperature at 65 ℃ and the pH at 10 +/-1, continuing aging for 2 hours after dropwise adding, then settling the obtained product for multiple times, pouring out supernatant until the pH of the supernatant is neutral, and drying at 70 ℃ overnight to obtain the ZrO 2 carrier.
(2) The above-mentioned ZrO 2 carrier was calcined at 550 ℃ for 4 hours in a hydrogen (H) atmosphere to obtain a modified ZrO 2 carrier (abbreviated as: ZrO 2 -P-H).
di, modified Au-ZrO 2 catalyst
The specific preparation method is the same as that of example 1.
comparative example 4 preparation of modified ZrO 2 Carrier (ZrO 2 -P-A) and modified Au-ZrO 2 catalyst (Au-ZrO 2 -P-A)
Preparation of modified ZrO 2 carrier
The preparation process comprises the following steps:
(1) Preparing zirconium dioxide by adopting a precipitation method (P), namely weighing 4.51g of ZrOCl 2 & 8H 2 O (AR, national drug group chemical reagent Co., Ltd.) into 70mL of water, uniformly stirring, marking as solution A, preparing 200mL of 0.5mol/L NaOH solution, marking as solution B, simultaneously dropwise adding the solution A and the solution B into 200mL of distilled water by a peristaltic pump, intensively stirring, keeping the reaction temperature at 65 ℃ and the pH at 10 +/-1, continuing aging for 2 hours after dropwise adding, then settling the obtained product for multiple times, pouring out supernatant until the pH of the supernatant is neutral, and drying at 70 ℃ overnight to obtain the ZrO 2 carrier.
(2) The ZrO 2 carrier was calcined at 550 ℃ for 4 hours under ｃA static air (A) atmosphere to obtain ｃA modified ZrO 2 carrier (abbreviated as: ZrO 2 -P-A).
Di, modified Au-ZrO 2 catalyst
The specific preparation method is the same as that of example 1.
Comparative example 5 preparation of modified ZrO 2 Carrier (ZrO 2 -P-A-H) and modified Au-ZrO 2 catalyst (Au-ZrO 2 -P-A-H)
preparation of modified ZrO 2 carrier
the preparation process comprises the following steps:
(1) Preparing zirconium dioxide by adopting a precipitation method (P), namely weighing 4.51g of ZrOCl 2 & 8H 2 O (AR, national drug group chemical reagent Co., Ltd.) into 70mL of water, uniformly stirring, marking as solution A, preparing 200mL of 0.5mol/L NaOH solution, marking as solution B, simultaneously dropwise adding the solution A and the solution B into 200mL of distilled water by a peristaltic pump, intensively stirring, keeping the reaction temperature at 65 ℃ and the pH at 10 +/-1, continuing aging for 2 hours after dropwise adding, then settling the obtained product for multiple times, pouring out supernatant until the pH of the supernatant is neutral, and drying at 70 ℃ overnight to obtain the ZrO 2 carrier.
(2) The ZrO 2 carrier was calcined at 550 ℃ for 4 hours in ｃA static air (A) atmosphere and then at 550 ℃ for 4 hours in ｃA hydrogen (H) atmosphere to obtain ｃA modified ZrO 2 carrier (abbreviated as: ZrO 2 -P-A-H).
Di, modified Au-ZrO 2 catalyst
The specific preparation method is the same as that of example 1.
comparative example 6
The conventional Au-ZrO 2 -HT-A catalyst of comparative mut mutexample 1 was calcined at 300 ℃ for 4 hours under a hydrogen atmosphere and taken out while being cooled to room temperature under a hydrogen atmosphere, and the obtained catalyst was abbreviated as Au-ZrO 2 -HT-A-300.
Comparative example 7
The conventional Au-ZrO 2 -HT-A catalyst of comparative mut mutexample 1 was calcined at 550 ℃ for 4 hours under a hydrogen atmosphere and taken out while being cooled to room temperature under a hydrogen atmosphere, and the obtained catalyst was abbreviated as Au-ZrO 2 -HT-A-550.
The catalysts prepared in the above example 1 and comparative examples 1 to 7 were examined and subjected to catalytic activity analysis, SEM analysis, BET specific surface and pore structure analysis, XPS analysis, and photoelectric property analysis.
1. Analysis of catalytic Activity
As shown in FIG. 1a, Au-ZrO 2 -HT-H catalyst using ZrO 2 -HT-H prepared by calcination in a hydrogen atmosphere as a carrier shows higher catalytic activity, and the CO conversion rates thereof at 200 ℃ and 300 ℃ reach 68.6% and 92.5%, respectively, comparison shows that the activity sequences of the respective catalysts are Au-ZrO 2 -HT-H > Au-ZrO 2 -HT-A-H > Au-ZrO 2 -HT-A. specifically, the CO conversion rates of Au-387ZrO 2-HT-H catalyst at 200 ℃ are respectively improved by 55% (from 44.2% to 68.6%) and 28% (from 53.4% to 68.6%) compared with comparative mutexamples 1 and 2.
Similarly, it can be seen from FIG. 1b that the activity sequences of the various catalysts are Au-ZrO 2 -P-H > Au-ZrO 2 -P-A-H > Au-ZrO 2 -P-A. specifically, the CO conversion of the Au-ZrO 2 -P-H catalyst at 200 ℃ is increased by 90% (from 27.9% to 53%) and 16% (from 45.7% to 53%), respectively, compared to Au-ZrO 2 -P-A-H and Au-ZrO 2 -P-A. it can be seen that the modified ZrO 2 -P-H support can cause the catalyst to exhibit higher catalytic activity with respect to the precipitation method.
In addition, in order to discuss the influence of the calcination in a hydrogen atmosphere on the carrier and the catalyst, the Au-ZrO 2 -HT-A catalyst is calcined in a hydrogen atmosphere at 300 ℃ and 550 ℃ respectively, so that Au-ZrO 2 -HT-A-300 (comparative mut mut mut mut mut mutexample 6) and Au-ZrO 2 -HT-A-550 (comparative mut mut mut mut mut mutexample 7) catalysts are obtained.
In addition, the catalytic activity of Au-ZrO 2 -HT-A-550 is higher than that of Au-ZrO 2 -HT-A-300, probably because the catalyst carrier can be modified in the hydrogen roasting at 550 ℃ although the high temperature of 550 ℃ can cause more serious gold nanoparticle agglomeration than 300 ℃, so that the catalyst carrier shows slightly higher activity, and the hydrogen roasting temperature of 300 ℃ is not enough to modify the carrier.
2. XRD analysis
As shown in FIG. 2, after being calcined at 550 ℃ in different atmospheres, the ZrO 2 of the support has monoclinic phase characteristic peaks at the positions of 24 °, 24.4 °, 28.1 °, 31.4 °, 34.1 °, 34.3 ° and 35.3 °, which are consistent with the positions of peaks in a ZrO 2 database (JCPDS 01-089-one 9066) and no impurity phase, and the XRD diffraction peak of the Au-ZrO 2 catalyst loaded with gold is almost the same as that of the support, which indicates that the crystal phase of the support is well maintained after being loaded, the grain size of the zirconium dioxide calcined at 550 ℃ is not changed, and the diffraction peak of metal Au is not found, indicating that Au is highly dispersed on the support.
3. SEM analysis
As shown in fig. 3, ZrO 2 particles in the modified ZrO 2 supports prepared from example 1 and comparative example 1 exhibited regular round plate-like structural morphology.
4. TEM analysis
As shown in a, b and g in FIG. 4, the degree of dispersion and the size of Au particles were almost the same on the Au-ZrO 2 -HT-H, Au-ZrO 2 -HT-A-H and Au-ZrO 2 -HT-A catalysts, indicating that the difference between their catalytic activities was not related to Au, and only the difference related to the ZrO 2 carrier was demonstrated.
As shown in FIG. 4c, the ZrO 2 -HT-H nanocrystal surface mut mutexhibited a region (disordered layer) with insignificant lattice fringes at a thickness of about 2nm, however, on HRTEM images of ZrO 2 -HT-A-H and ZrO 2 -HT-A, no apparent disordered layer was found near the surface region (FIGS. 2-4e, H).
As shown in FIGS. 4f and i, when Au was supported on the ZrO 2 support, the Au-ZrO 2 -HT-H retained the microstructure consisting of crystalline nuclei and disordered layers despite the reduction of the surface disordered layer to about 1nm thickness.
The results showed that the H 2 atmosphere caused a rearrangement of the surface structure of the ZrO 2 support, and to verify its stability, we exposed the hydrogen-calcined support to air for several months and immersed in water for a long time during the preparation of the Au catalyst, and found that the disordered layer on the surface was not destroyed, demonstrating high stability.
5. BET specific surface and pore Structure analysis
As can be seen from Table 1, the specific surface area of ZrO 2 -HT-H (24.6m 2/g) is the largest compared to ZrO 2 -HT-A and ZrO 2 -HT-A-H.
TABLE 1 texture Performance Table for ZrO 2 support and Au/ZrO 2 catalyst
As shown in FIG. 5, the supports prepared in example 1 and comparative examples 1 and 2 had 2 hysteresis loops and were of the double mesoporous type ZrO 2. it can be seen from the figure that the relative pressure (P/P 0) at the separation of the adsorption and desorption curves in the hysteresis loops of the ZrO 2 -HT-H support was the smallest, the smaller the pore diameter, the lower the saturation vapor pressure required for agglomeration, and the lower the relative pressure at the separation of the adsorption and desorption curves in the hysteresis loops, indicating the smaller the pore diameter of the capillary pores, and vice versa, indicating the smallest pore diameter of the ZrO 2 -HT-H support, which is consistent with the results in Table 1 that the ZrO 2 -HT-H support had the smallest average pore diameter (30 nm).
As shown in FIG. 6, the pore diameters of the carrier and the catalyst are mainly distributed in two types, namely, 3-6 nm mesoporous pores and about 30-40 nm stacking pores, and after gold loading, the pore diameter distribution is not changed, wherein the pore diameter of the ZrO 2 -HT-H carrier is the smallest, and the pore diameters of the ZrO 2 -HT-A carrier and the ZrO 2 -HT-A-H carrier are almost the same.
according to the comparison of the specific surface sizes in Table 1, the ZrO 2 -HT-H carrier not only has a small pore size but also has a large specific surface, which shows that it has many more and smaller micropore structures inside than the ZrO 2 -HT-A carrier and the ZrO 2 -HT-A-H carrier, and improves the utilization of the pore inner surface, thereby showing better catalytic activity.
6. XPS characterization
as shown in FIG. 7A, both ZrO 2 -HT-H and ZrO 2 -HT-A-H have much less surface-OH than ZrO 2 -HT-A, indicating that the amount of oxygen atoms present in ZrO 2 -HT-H and ZrO 2 -HT-A-H is less than that of normal zirconium dioxide, and ZrO 2 -HT-H shows less surface-OH. the results indicate that surface-OH is reduced due to H 2 reduction during hydrogen calcination, thereby forming surface oxygen vacancies.
As shown in FIG. 7B, only Au 0 (elemental gold with a valence of 0) appears in Au-ZrO 2 -HT-H, while Au 0 and Au 3+ appear in Au-ZrO 2 -HT-A and Au-ZrO 2 -HT-A-H, considering that the gold source employed in the present invention is HAuCl 4 (Au 3+), it is inferred that Au 0 is obtained due to the transfer of charges on the reduced oxygen vacancies on the surface of the support to Au particles, therefore, the amount of Au 0 supported on ZrO 2 -HT-H during the deposition of gold (Au (OH) 3) is far greater than that on ZrO 2 -HT-A and ZrO 2 -HT-A-H, and thus the catalytic activity of the Au 0 supported on ZrO 2 -HT-H is better than that of the Au 0 supported on ZrO 2 -HT-A and ZrO 2 -HT-A-H for the CO oxidation reaction, compared to that of Au 3+ -ZrO 39 2.
The results show that the catalytic activity of the catalysts is not dependent on the difference in their gold loading, but on the difference in the valence state of Au, which is influenced by the number of oxygen vacancies on the surface of the support.
7. EPR characterization
As shown in FIG. 8, both ZrO 2 -HT-H and Au-ZrO 2 -HT-H produced significant EPR signals due to the single electron O 2 · - radical trapped by O 2 (from air) adsorbed at the oxygen vacancy, however, no signal was found in ZrO 2 -HT-A, Au-ZrO 2 -HT-A, ZrO 2 -HT-A-H, and Au-ZrO 2 -HT-A-H.
8. PL characterization
FIG. 9 is a fluorescence spectrum of various ZrO 2 carriers and Au-ZrO 2 catalysts, from which it can be seen that electrons in ZrO 2 -HT-A-H and ZrO 2 -HT-H carriers are not easily transited from an mut mut mut mutexcited state back to a ground state, and their electron-hole recombination probability is reduced, compared to ZrO 2 -HT-A carriers.
9. Analysis of photoelectric properties
Electrochemical impedance measurements of various ZrO 2 supports and Au-ZrO 2 catalysts were made in the dark at a frequency of 10kHz to investigate the effect of hydrogen calcination on their electronic properties all samples showed positive slopes in the Mott-Schottky plot (FIG. 10) as expected for n-type semiconductors, the donor densities for these samples were calculated from the slopes in the Mott-Schottky plot:
Nd＝(2/e0εε0)[d(1/C2)/dV]-1
Where E 0 is the electronic charge, ∈ is the dielectric constant of TiO 2 (∈ 170), ∈ 0 is the vacuum dielectric constant (8.85E-12F/m), N d is the donor density, and V is the applied bias at the electrode.
ZrO 2 -HT-A, ZrO 2 -HT-A-H, and ZrO 2 -HT-H calculated electron densities of 2.5 × 10 22 cm -3, 9.6 × 10 22 cm -3, and 3.4 × 10 23 cm -3, respectively, while the order of magnitude of electron densities is unchanged after loading Au, Au-ZrO 2 -HT-H (4.3 × 10 24 cm -3) > Au-ZrO 2 -HT-A-H (7 × 10 23 cm -3) > Au-ZrO 2 -HT-A (1.7 × 10 23 cm -3), and the electron density is increased by about 10 times compared to the corresponding support.

Claims (5)

1. A modified Au-ZrO 2 catalyst comprises a carrier and an active component, and is characterized in that the carrier is obtained by roasting and modifying ZrO 2 under a hydrogen atmosphere, ZrO 2 is prepared by a hydrothermal method, the active component is elemental gold, the roasting condition of the carrier is that the carrier is roasted at a temperature of 500-600 ℃ for 2-6 hours under normal pressure, and the electron densities of the modified ZrO 2 carrier and the modified Au-ZrO 2 catalyst are 1 x 10 23 -9 x 10 23 cm -3 and 1 x 10 24 -9 x 10 24 cm -3 respectively.
2. the modified Au-ZrO 2 catalyst of claim 1, wherein the support is a double mesoporous ZrO 2 comprising mesopores of 3 to 6nm and packed pores of 30 to 40 nm.
3. The modified Au-ZrO 2 catalyst of claim 1, wherein the modified Au-ZrO 2 catalyst has a specific surface area of 20-30 m 2/g and an average pore radius of 20-40 nm.
4. the use of the modified Au-ZrO 2 catalyst according to any one of claims 1 to 3 in the preparation of hydrogen by water gas shift reaction.
5. A method for preparing hydrogen by using the modified Au-ZrO 2 catalyst of any one of claims 1 to 3 to perform water gas shift reaction, wherein the reaction temperature is 200-600 ℃.
CN201710344789.6A 2017-05-16 2017-05-16 Au-ZrO 2 catalyst and application thereof Active CN107096532B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201710344789.6A CN107096532B (en) 2017-05-16 2017-05-16 Au-ZrO 2 catalyst and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201710344789.6A CN107096532B (en) 2017-05-16 2017-05-16 Au-ZrO 2 catalyst and application thereof

Publications (2)

Publication Number Publication Date
CN107096532A CN107096532A (en) 2017-08-29
CN107096532B true CN107096532B (en) 2019-12-10

Family

ID=59668890

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201710344789.6A Active CN107096532B (en) 2017-05-16 2017-05-16 Au-ZrO 2 catalyst and application thereof

Country Status (1)

Country Link
CN (1) CN107096532B (en)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6821494B2 (en) * 2001-07-31 2004-11-23 Utc Fuel Cells, Llc Oxygen-assisted water gas shift reactor having a supported catalyst, and method for its use
WO2005087656A1 (en) * 2004-03-10 2005-09-22 Johnson Matthey Public Limited Company Water gas shift catalyst
CN1894035A (en) * 2003-12-19 2007-01-10 国际人造丝公司 Zirconia containing support material for catalysts
CN101954279A (en) * 2010-09-20 2011-01-26 福州大学 Catalyst for low-temperature water-gas-shift reaction under hydrogenous reformed gas and preparation method thereof
CN102389795A (en) * 2011-09-29 2012-03-28 复旦大学 Nano gold catalyst for use in hydrogen production by decomposition of formic acid and preparation method thereof
CN103272600A (en) * 2013-06-07 2013-09-04 福州大学 Supported copper-iron water coal gas shift catalyst and preparation method thereof
CN103599779A (en) * 2013-11-13 2014-02-26 福州大学 CuO/ZrO2 water-gas shift catalyst and preparation method thereof
CN105727944A (en) * 2016-03-25 2016-07-06 福州大学 Preparation method of ZrO2 nanosheet supported ruthenium catalyst
CN106622199A (en) * 2017-01-25 2017-05-10 闽江学院 Large surface area porous ZrO2 mesoscopic crystal

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6821494B2 (en) * 2001-07-31 2004-11-23 Utc Fuel Cells, Llc Oxygen-assisted water gas shift reactor having a supported catalyst, and method for its use
CN1894035A (en) * 2003-12-19 2007-01-10 国际人造丝公司 Zirconia containing support material for catalysts
WO2005087656A1 (en) * 2004-03-10 2005-09-22 Johnson Matthey Public Limited Company Water gas shift catalyst
CN101954279A (en) * 2010-09-20 2011-01-26 福州大学 Catalyst for low-temperature water-gas-shift reaction under hydrogenous reformed gas and preparation method thereof
CN102389795A (en) * 2011-09-29 2012-03-28 复旦大学 Nano gold catalyst for use in hydrogen production by decomposition of formic acid and preparation method thereof
CN103272600A (en) * 2013-06-07 2013-09-04 福州大学 Supported copper-iron water coal gas shift catalyst and preparation method thereof
CN103599779A (en) * 2013-11-13 2014-02-26 福州大学 CuO/ZrO2 water-gas shift catalyst and preparation method thereof
CN105727944A (en) * 2016-03-25 2016-07-06 福州大学 Preparation method of ZrO2 nanosheet supported ruthenium catalyst
CN106622199A (en) * 2017-01-25 2017-05-10 闽江学院 Large surface area porous ZrO2 mesoscopic crystal

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
Highly efficient Au/ZrO2 catalysts for low-temperature wateregas shift reaction: Effect of pre-calcination temperature of ZrO2;Yanjie Zhang et al;《i n t e rna t i onal journal o f hydrogen energy》;20120628;第37卷;第12292-12300页 *
Influence of zirconia crystal phase on the catalytic performance of Au/ZrO2 catalysts for low-temperature water gas shift reaction;Juan Li et al;《Applied Catalysis A: General》;20071026;第334卷;第321-329页 *
以水热法合成的 ZrO2 负载 Au 催化剂上的低温水煤气变换反应;张燕杰等;《催化学报》;20121231;第33卷(第2期);第230-236页 *
纳米ZrO2在O2/H2气中的表面效应;王新平等;《高等化学学报》;20020731;第23卷(第7期);第1343-1346页 *

Also Published As

Publication number Publication date
CN107096532A (en) 2017-08-29

Similar Documents

Publication Publication Date Title
CN109309212B (en) Carbon-coated cobalt nano composite material and preparation method thereof
Guo et al. Hollow, porous, and yttrium functionalized ZnO nanospheres with enhanced gas-sensing performances
Song et al. Triple-shelled ZnO/ZnFe2O4 heterojunctional hollow microspheres derived from Prussian Blue analogue as high-performance acetone sensors
Wen et al. A facile fluorine-mediated hydrothermal route to controlled synthesis of rhombus-shaped Co 3 O 4 nanorod arrays and their application in gas sensing
Papadas et al. A high surface area ordered mesoporous BiFeO 3 semiconductor with efficient water oxidation activity
Qian et al. Direct growth of NiCo 2 O 4 nanostructures on conductive substrates with enhanced electrocatalytic activity and stability for methanol oxidation
US20130089739A1 (en) Nanostructured metal oxides and mixed metal oxides, methods of making these nanoparticles, and methods of their use
CN107115861B (en) A kind of Au-TiO2-xCatalyst and its application
Rong et al. Highly selective and sensitive methanol gas sensor based on molecular imprinted silver-doped LaFeO3 core–shell and cage structures
Meng et al. One-step synthesis and the enhanced trimethylamine sensing properties of Co3O4/SnO2 flower-like structures
US9498774B2 (en) Composite body in which first metal-containing particles and second metal-containing particles are supported on carbon material or connected by carbon material, and method for producing same
Chen et al. Template-free synthesis of 3D hierarchical nanostructured NiCo 2 O 4 mesoporous ultrathin nanosheet hollow microspheres for excellent methanol electrooxidation and supercapacitors
US20200056295A1 (en) Process for preparation of metal oxides nanocrvstals and their use for water oxidation
Fihri et al. Nanoroses of nickel oxides: synthesis, electron tomography study, and application in CO oxidation and energy storage
Chen et al. Surfactant-additive-free synthesis of 3D anatase TiO 2 hierarchical architectures with enhanced photocatalytic activity
Melchionna et al. Synthesis and properties of cerium oxide-based materials
KR20200028051A (en) Anisotropic noble metal nanoparticle core - cobalt sulfide shell nanocage, synthetic method thereof, and heterogeneous catalyst containing thereof
Jiang et al. Bimetal composites for photocatalytic reduction of CO 2 to CO in the near-infrared region by the SPR effect
Yu et al. Preparation, formation mechanism and photocatalysis of ultrathin mesoporous single-crystal-like CeO 2 nanosheets
Marikutsa et al. Improved H2S sensitivity of nanosized BaSnO3 obtained by hydrogen peroxide assisted sol-gel processing
US20130315787A1 (en) Nanocrystals and methods and uses thereof
Fan et al. Synthesis and gas sensing properties of β-Fe2O3 derived from Fe/Ga bimetallic organic framework
Zhuang et al. New nitrogen-doped graphene/MOF-modified catalyst for fuel cell systems
Li et al. In situ synthesis of well crystallized rhodium sulfide/carbon composite nanospheres as catalyst for hydrochloric acid electrolysis
Liu et al. Janus coordination polymer derived PdO/ZnO nanoribbons for efficient 4-nitrophenol reduction

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant