CN109701579A - A kind of nanocrystalline colloid catalyst of photoresponse enhancing catalysis H2-producing capacity - Google Patents

Abstract

The present invention relates to the nanocrystalline colloid catalyst that a kind of photoresponse enhances catalysis H2-producing capacity.It is conducive to the dispersion degree for improving active component with lower activation energy and higher specific surface area, realizes that catalyst up to repeatedly utilizes, while its cost is low, safety and environmental protection.Step of the present invention is 1, using melamine as raw material, prepares g-C using calcination method₃N₄Then blocks obtains g-C with grinding again₃N₄Powder；2,0.00314g ferric trichloride is dissolved in 20mL deionized water and is stirred evenly；3,60mg g-C is taken₃N₄Powder is dissolved in 20mL deionized water, is stirred evenly, and is uniformly mixed with step 2 acquired solution and ultrasound 1h；4, it takes 3.96g protective agent polyvinylpyrrolidone (PVP) to be dissolved in 20mL deionized water, and is mixed with the resulting mixed solution of step 3；5, gained mixed solution, which is placed in pyroreaction kettle, seals, and is placed under the conditions of 180 DEG C, calcines 12h；6, opening reaction kettle obtains g-C after temperature drops to room temperature₃N₄/Fe₂O₃Photoresponse nanocrystalline colloid catalyst.

Description

A kind of nanocrystalline colloid catalyst of photoresponse enhancing catalysis H2-producing capacity

Technical field

The invention belongs to produce hydrogen energy source technical field, further to a kind of g-C₃N₄/Fe₂O₃Photoresponse enhancing catalysis produces The preparation of the nanocrystalline colloid catalyst of hydrogen performance and the applied technical field of photocatalysis sodium borohydride highly effective hydrogen yield, and in particular to A kind of nanocrystalline colloid catalyst of photoresponse enhancing catalysis H2-producing capacity.

Background technique

Hydrogen Energy is greatly promoted the development of field of renewable energy as a kind of clean energy resource, its use.However, In the application of Hydrogen Energy, most production hydrogen technique is confined to the factors such as the controlled release performance difference of hydrogen, practice have shown that most effective It is that production hydrogen is catalyzed by catalyst with safest method, solid hydride can generally pass through thermal decomposition and solvolysis etc. Method, but thermally decompose and need longer induction time (about 3h) and higher temperature, therefore limit its application, solvolysis Rule can realize the efficient release of hydrogen under any temperature strip part by suitable catalyst.Catalytic chemistry hydrogenates produce hydrogen There are many catalyst type, and general mainly includes three classes: single-metal reforming catalyst, bimetallic catalyst and loaded catalyst etc.. Single-metal reforming catalyst research is most widely Pt metal and the catalyst of Ru, and lower activation energy and higher specific surface area determine The disadvantages of its high catalytic activity, but because of its higher cost, the ingredient single reunion be easy to causeing, limits the extensive of its Using.Therefore, under the premise of not influencing the catalytic activity of catalyst, it is big for developing the transition-metal catalyst of low-cost and high-performance Gesture is become.The catalyst such as Co, Ni, Fe are easy to get due to preparing raw material, and price is relatively inexpensive, and domestic and international relevant report has very much.But office It is limited to that transition metal material is easy to reunite and catalytic activity is far below noble metal catalyst, has severely impacted noble metal catalyst Service life cycle often can only achieve 1 to 2 lower catalysis and produce hydrogen activity.

Summary of the invention

It is an object of the invention in view of the above problems, provide a kind of g-C₃N₄/Fe₂O₃The nanocrystalline glue of photoresponse Body material has lower activation energy (14.57kJmol^-1) and higher specific surface area, be conducive to point for improving active component Divergence realizes that catalyst up to repeatedly utilizes, while its cost is low, safety and environmental protection.

To achieve the object of the present invention, technical solution of the present invention is the following steps are included: a kind of photoresponse enhancing catalysis produces The nanocrystalline colloid catalyst of hydrogen performance, is made by following methods, and the method includes the following steps,

Step (1): using melamine as raw material, g-C is prepared using calcination method₃N₄Then blocks obtains g- with grinding again C₃N₄Powder；

Step (2): 0.00314g ferric trichloride is dissolved in 20mL deionized water and is stirred evenly；

Step (3): 60mg g-C is taken₃N₄Powder is dissolved in 20mL deionized water, is stirred evenly, and molten with step (2) gained Liquid is uniformly mixed and ultrasound 1h；

Step (4): 3.96g protective agent polyvinylpyrrolidone (PVP) is taken to be dissolved in 20mL deionized water, and and step (3) resulting mixed solution mixing；

Step (5): gained mixed solution, which is placed in pyroreaction kettle, to be sealed, and is placed under the conditions of 180 DEG C, calcines 12h；

Step (6): opening reaction kettle obtains g-C after temperature drops to room temperature₃N₄/Fe₂O₃The catalysis of photoresponse nanocrystalline colloid Agent.

Compared with prior art, the invention has the advantages that

1, the g-C described in the present invention₃N₄/Fe₂O₃Colloid catalyst is prepared by hydrothermal synthesis method, is compared to often Used low temperature nitrogen protects reduction method when the colloid catalyst preparation of rule, and method is simpler, facilitates operation, at low cost It is honest and clean, safety and environmental protection.

2, conventional colloid catalyst, base material g-C of the present invention are compared to₃N₄Not only there is big ratio Surface area is conducive to the dispersion of metallic nano crystal, while it can absorb visible light and obtain light induced electron, further promotes catalysis The promotion of efficiency.The Fe that the present invention uses₂O₃Belong to cheap transition metal material, can further reduce the cost, while also having good Good visible light-responded performance.

3, the g-C that the present invention is prepared₃N₄/Fe₂O₃Colloid catalyst, catalysis hydrogen-producing speed have reached (1072mol H₂·h^-1·mol·M^-1), it is almost suitable with the catalytic efficiency of Ni/Au/Co noble metal base rubber body catalyst of colloid protection (1170mol H₂·h^-1·mol·M^-1), realize effectively reduce cost under conditions of, maintain and noble metal is comparable urges Change efficiency, while there is the circulation 5 times high catalysis used to produce hydrogen utilization rate.

4, in the preparation process of product of the present invention, due to g-C₃N₄With Fe₂O₃Between photo-excited electron and hole occurs Fine dispersion and transmitting, improve g-C₃N₄/Fe₂O₃The catalysis of colloid catalyst produces hydrogen activity (1072mol H₂·h^-1· mol·M^-1), it is compared under dark condition 39% hydrogen generation efficiency of amplification.

Detailed description of the invention

Fig. 1 is g-C prepared by embodiment 1₃N₄/Fe₂O₃The catalysis of-X% photocatalytic nanometer crystalline substance colloidal materials produces hydrogen figure；

Fig. 2 is g-C prepared by embodiment 2₃N₄/Fe₂O₃Production hydrogen comparison diagram under catalysis material dark and illumination condition；

Fig. 3 is g-C prepared by embodiment 3₃N₄/Fe₂O₃The catalysis of photocatalytic nanometer crystalline substance colloidal materials produces hydrogen cycle life Figure.

Specific embodiment

The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.

Photoresponse composite catalyst is intended to drive the catalysis of catalyst to produce hydrogen activity by illumination, can be effectively reduced simultaneously The reunion of nano metal and inactivation.Wherein, polymer semiconductor, class graphite carboritride (g-C₃N₄) as a kind of " sustainable The light responsive material of the two-dimensional of development " has for example good thermal stability of many merits and chemical stability, in metal There is an adjustable free electron structure in portion.In addition, the band-gap energy (2.7eV) of appropriateness can directly utilize visible light.These Unique performance makes g-C₃N₄Possess various potential application values, if energy is converted, organic synthesis, pollutant process, hydrogen Production.

A kind of preparation method of the nanocrystalline colloid catalyst of photoresponse enhancing catalysis H2-producing capacity provided by the invention is: Under the conditions of certain temperature, according to a certain ratio by liquor ferri trichloridi, g-C₃N₄Powder ultrasonic disperses solution and PVP colloid is molten Liquid mixing, is prepared g-C by hydrothermal synthesis method₃N₄/Fe₂O₃The nanocrystalline colloid material of photoresponse enhancing catalysis H2-producing capacity Material.

Embodiment:

The present embodiment prepares g-C₃N₄/Fe₂O₃Photoresponse colloid catalyst, specifically includes the following steps:

Step (1): using melamine as raw material, g-C is prepared using calcination method₃N₄Then blocks obtains g- with grinding again C₃N₄Powder.

Step (2): 0.00314g ferric trichloride is dissolved in 20mL deionized water and is stirred evenly.

Step (3): 60mg g-C is taken₃N₄Powder is dissolved in 20mL deionized water, is stirred evenly, and with step 2 acquired solution Uniformly mixed and ultrasound 1h.

Step (4): taking 3.96g protective agent polyvinylpyrrolidone (PVP) to be dissolved in 20mL deionized water, and with step 3 Resulting mixed solution mixing.

Step (5): step 4 gained mixed solution is placed in pyroreaction kettle and is sealed, is placed under the conditions of 180 DEG C, forges Burn 12h.

Step (6): to which after step 5, opening reaction kettle obtains g-C after temperature drops to room temperature₃N₄/Fe₂O₃Photoresponse glue Body catalyst.

G-C described in step (1)₃N₄It is prepared using calcination method.

G-C is prepared using calcination method₃N₄Concrete technology flow process: weigh 3g melamine and 7g urea be put into mortar and grind Mill uniformly, is fitted into sample in 20mL deionized water later, is vigorously stirred in 80 DEG C of water-baths, after water is evaporated, sample It is ground from being newly put into mortar, uniformly rear sealing to be ground is put into crucible, later with 5 DEG C of min^-1Rate be warming up to 520 DEG C, while two hours are kept the temperature, to after reaction, take out sample and it is ground into powdery collection.

The comparative experiments of the colloid catalyst of different metal ions incorporation:

The colloid catalyst of different metal ions incorporation is prepared first

The present embodiment prepares g-C₃N₄/Fe₂O₃Photoresponse colloid catalyst, specifically includes the following steps:

Step (1): using melamine as raw material, g-C is prepared using calcination method₃N₄Then blocks obtains g- with grinding again C₃N₄Powder.

Step (2): 0.00157,0.00314 and 0.00628g ferric trichloride are dissolved in 3 20mL deionized waters respectively In and stir evenly.

Step (3): 3 parts of 60mg g-C are taken respectively₃N₄Powder is dissolved in respectively in 20mL deionized water, is stirred evenly, and with step Rapid 2 acquired solution is uniformly mixed and ultrasound 1h.

Step (4): taking 3.96g protective agent polyvinylpyrrolidone (PVP) to be dissolved in 20mL deionized water, and with step 3 Resulting mixed solution mixing.

Step (5): step 4 gained mixed solution is placed in pyroreaction kettle and is sealed, is placed under the conditions of 180 DEG C, forges Burn 12h.

Step (6): to which after step 5, opening reaction kettle obtains g-C after temperature drops to room temperature₃N₄/Fe₂O₃- X% (0.5,1,2) photoresponse colloid catalyst.

Secondly it is tested using following step:

g-C₃N₄/Fe₂O₃Photoresponse colloid catalyst is catalyzed sodium borohydride highly effective hydrogen yield.

Measurement alkalinity NaBH4 solution (pH=12) generates H under the effect of the catalyst₂Volume and rate, it is basic herein The upper hydrogen desorption capacity calculated in the catalyst unit time, and carry out with this catalytic activity of comparative catalyst.The test of catalytic performance Journey is as follows: prepared g-C being added into three-necked flask₃N₄/Fe₂O₃Nanocrystalline colloid solution 60mL, adjusting reaction temperature is 30 DEG C, 10mL, the alkaline NaBH of 30mM are added into three-necked flask by separatory funnel₄Solution opens lamp source.Reaction to be catalyzed is opened After beginning, H under different time is measured by drainage₂Yield.

Conclusion explanation:

With reference to Fig. 1, prepared g-C can be significantly found₃N₄/Fe₂O₃- 2% photoresponse nanocrystalline colloid material is urged Change active highest, 9min can produce the hydrogen of 30mL, realize 100% catalytic effect.

With reference to Fig. 2, hence it is evident that find out, g-C prepared by the present invention₃N₄/Fe₂O₃In -2% photoresponse nanocrystalline colloid material, Under dark condition, 12min produces 18.5mL hydrogen, under illumination condition, produces 30mL hydrogen, hydrogen generation efficiency amplification 39%.

With reference to Fig. 3, it can be seen that prepared g-C₃N₄/Fe₂O₃- 2% photoresponse nanocrystalline colloid material has good Service life, the catalysis hydrogen output that circulation is 5 times are all relatively good.

G-C provided by the invention₃N₄/Fe₂O₃The dispersibility of catalyst not only can be improved in photoresponse colloid catalyst, has The reunion for preventing catalyst of effect, makes it show excellent reactivity and catalytic efficiency, and g-C₃N₄With Fe₂O₃Between The fine dispersion and transmitting that photo-excited electron and hole occurs, advantageously reduce the recombination rate in photo-excited electron and hole, thus Improve the Photocatalyzed Hydrogen Production performance of catalyst.Its catalysis hydrogen-producing speed (TOF) value has reached 1072mol H₂.1072^{- 1}.mol.M^-1, basically reached Ni/Au/Co noble metal base rubber body catalyst (the 1170mol H of colloid protection₂.h^-1.mol.M^-1) Hydrogen generation efficiency.

Claims (1)

1. a kind of nanocrystalline colloid catalyst of photoresponse enhancing catalysis H2-producing capacity, is made, the method packet by following methods Include following step:

Step (1): using melamine as raw material, g-C is prepared using calcination method₃N₄Then blocks obtains g-C with grinding again₃N₄ Powder；

Step (2): 0.00314g ferric trichloride is dissolved in 20mL deionized water and is stirred evenly；

Step (3): 60mg g-C is taken₃N₄Powder is dissolved in 20mL deionized water, is stirred evenly, and mixed with step (2) acquired solution Close uniform and ultrasonic 1h；

Step (4): taking 3.96g protective agent polyvinylpyrrolidone (PVP) to be dissolved in 20mL deionized water, and with step (3) institute The mixed solution mixing obtained；

Step (5): gained mixed solution, which is placed in pyroreaction kettle, to be sealed, and is placed under the conditions of 180 DEG C, calcines 12h；

Step (6): opening reaction kettle obtains g-C after temperature drops to room temperature₃N₄/Fe₂O₃Photoresponse nanocrystalline colloid catalyst.