CN-115301266-B - Graphite-phase carbon nitride/polyaniline/nickel sulfide heterostructure photocatalyst and preparation method thereof

Abstract

The invention relates to a preparation method of a g-C 3 N 4 -PANI-NiS heterostructure photocatalyst, which comprises (1) preparing a g-C 3 N 4 nano sheet, namely placing a carbon nitrogen source into a ceramic crucible with a cover, calcining in a muffle furnace to obtain light yellow g-C 3 N 4 powder, placing the g-C 3 N 4 powder into a porcelain boat, calcining for the second time in the air atmosphere of a tubular furnace, washing a synthesized sample with deionized water and absolute ethyl alcohol for three times, drying overnight in a vacuum drying oven, grinding to obtain white g-C 3 N 4 nano sheets, and (2) preparing the g-C 3 N 4 -PANI by dispersing aniline into 0.1mol/L HCl solution, adding a proper amount of ammonium persulfate and g-C 3 N 4 nano sheets into the mixed solution, continuously stirring under ice bath to obtain green precipitate, namely a product, (3) dispersing the g-C 3 N 4 -PANI in the deionized water by ultrasonic waves, adding a nickel source and a proper amount of triethanolamine, obtaining a uniformly dispersed suspension, and sequentially carrying out the ultrasonic irradiation on the suspension in a room temperature under the condition of a xenon lamp, and carrying out the heterogeneous structure of the catalyst by using the PANI. The g-C 3 N 4 -PANI-NiS heterostructure photocatalyst prepared by the method has good application in photocatalysis hydrogen evolution.

Inventors

• QIAN JINGWEN
• XU SONGSONG
• WANG XIANBAO

Assignees

• 湖北大学

Dates

Publication Date

20260508

Application Date

20210508

Claims (2)

1. 1. The preparation method of the g-C 3 N 4 -PANI-NiS heterostructure photocatalyst is characterized by comprising the following steps of: (1) The preparation of the g-C 3 N 4 nanosheets comprises the steps of placing a carbon-nitrogen source in a ceramic crucible with a cover, calcining in a muffle furnace to obtain pale yellow g-C 3 N 4 powder, placing the g-C 3 N 4 powder in a ceramic boat, performing secondary calcination in the air atmosphere of a tubular furnace, washing a synthesized sample with deionized water and absolute ethyl alcohol for three times, drying in a vacuum drying oven overnight, and grinding to obtain white g-C 3 N 4 nanosheets; (2) Dispersing aniline in dilute hydrochloric acid solution, adding proper amount of ammonium persulfate and g-C 3 N 4 nanometer sheet into the mixed solution, and continuously stirring under ice bath to obtain green precipitate as the product; (3) The preparation of g-C 3 N 4 -PANI-NiS comprises the steps of dispersing g-C 3 N 4 -PANI in deionized water by ultrasonic, sequentially adding a nickel source, a sulfur source and a proper amount of triethanolamine, carrying out ultrasonic treatment to obtain a uniformly dispersed suspension, irradiating the suspension in a photocatalytic reactor at room temperature by using a xenon lamp to obtain the g-C 3 N 4 -PANI-NiS composite photocatalyst, and drying.
2. 2. The preparation method of the catalyst according to claim 1, wherein in the step (1), the carbon and nitrogen source is monoamine, dicyandiamide, melamine, urea or thiourea, in the step (1), the first calcination temperature is 300-1000 ℃, the second calcination temperature is 100-500 ℃, in the step (2), the stirring time is 1-10 h, the dilute hydrochloric acid concentration is 0.05-0.5mol/L, in the step (2), the ultrasonic time is 0.5-2 h, in the step (3), the nickel source is nickel nitrate, nickel chloride, nickel sulfate, nickel bromide or hydroxy nickel, in the step (3), the sulfur source is thiourea, thioacetamide or cysteine, in the step (3), the irradiation time is 10-60 min, and the drying temperature in the step (3) is 50-80 ℃.

Description

Graphite-phase carbon nitride/polyaniline/nickel sulfide heterostructure photocatalyst and preparation method thereof Technical Field The invention relates to a photocatalytic material, in particular to a preparation method of a g-C 3N4 -PANI-NiS heterostructure photocatalyst, and belongs to the technical field of material synthesis. Background Fossil energy, by which humans survive, is an unsustainable energy source, whose storage is limited. With the rapid development of global industry, the shortage of fossil fuels has led to a serious concern for the increasing energy demand of modern society, and the combustion of fossil fuels has also caused an increasing environmental problem, so that the development of clean and sustainable energy with low cost is of great significance. Since the pioneering paper published in Fujishima in 1972, it was discovered that semiconductor photocatalytic technology can decompose water into hydrogen gas, converting low density solar energy into a high density hydrogen energy form for storage. From the two aspects of energy utilization and environmental protection, hydrogen energy is a renewable energy source with high energy and pollution-free combustion, and can be called an ideal energy source in the 21 st century. Therefore, development of hydrogen energy is not easy. The non-metal polymer semiconductor graphite phase carbon nitride (g-C 3N4) has been actively and widely studied in the field of photocatalytic water decomposition due to the advantages of wide precursor source, simple preparation method, environmental friendliness, no heavy metal pollution, high photochemical stability, energy band structure suitable for photocatalytic hydrogen production/oxygen production and the like. However, the bottleneck problems of low carrier separation rate of g-C 3N4, weak water oxidation driving force and limited visible light absorption are not solved effectively, and the development of g-C 3N4 photocatalytic total-decomposition water is severely limited. To overcome these problems, various strategies have been employed to increase the photocatalytic hydrogen production efficiency of g-C 3N4, including adjusting the size, morphology, electronic structure, metallic or non-metallic deposition, and the configuration of heterostructures, among others. Among them, establishing a heterogeneous connection type photocatalytic system is an effective method for promoting charge separation of photogenerated electron-hole pairs. Polyaniline (PANI) is a P-type conductive polymer with a high light absorption coefficient and high electron mobility in the visible light range, and is receiving a great deal of attention in the field of photocatalysis. PANI and g-C 3N4 both have pi conjugated structures, which are more likely to be compatible to form composites. When Polyaniline (PANI) is coated on the surface of g-C 3N4, the solar energy utilization rate of g-C 3N4 is improved, a transmission channel is provided for the separation of photo-generated electron-hole pairs, and the separation of photo-generated carriers is promoted, so that the photocatalysis performance is improved. In the photocatalytic hydrogen production process, introducing a cocatalyst on the surface of the photocatalyst is one of the most effective methods for improving the photocatalytic performance, because it has the advantages of accelerating interfacial electron transfer, inhibiting photoexcitation charge recombination and increasing effective active sites. As a transition metal chalcogenide, niS has excellent electrochemical performance and good conductivity, and is an effective promoter in photocatalytic hydrogen evolution reaction. In addition, compared with other non-noble metals, the NiS has lower activation energy when forming Ni-H bonds with water adsorbed on the surface in the proton reduction process, and promotes the hydrogen adsorption reduction-desorption process, thereby obviously enhancing the photocatalytic hydrogen production reaction. Disclosure of Invention The g-C 3N4 nano sheet is synthesized by adopting a thermal polymerization method, then aniline is taken as a monomer by adopting a chemical oxidation polymerization method, ammonium persulfate is taken as an oxidant, the synthesized Polyaniline (PANI) is coated on the g-C 3N4 nano sheet to prepare the g-C 3N4 -PANI, and then the NiS is loaded on the g-C 3N4 -PANI by adopting a photo-deposition method to prepare the g-C 3N4 -PANI-NiS photocatalyst, so that the photocatalytic hydrogen evolution performance of the prepared g-C 3N4 -PANI-NiS photocatalyst under visible light is up to 7.818mmol/g -1h-1. The invention provides a preparation method of a g-C 3N4 -PANI-NiS composite photocatalyst, which is characterized by comprising the following steps: (1) The preparation of the g-C 3N4 nanosheets comprises the steps of placing a carbon-nitrogen source in a ceramic crucible with a cover, calcining in a muffle furnace to obtain pale yellow g-C 3N4 powder, pla