A kind of ultra-thin silicon nanosheet photocatalyst and its preparation method and application

Abstract

The invention discloses an ultra-thin silicon nanosheet photocatalyst and its preparation method and application. It uses crystalline silicon powder as a precursor, disperses it into a solvent after being dipped in an ultra-low temperature liquid gas, and then assisted the liquid phase by ultrasonic waves. The ultra-thin silicon nano-sheet suspension is obtained by peeling off, and after the suspension is centrifuged and freeze-dried, an ultra-thin silicon nano-sheet photocatalyst with a thickness of 0.3-2.1 nm and a size of 0.1-6.5 μm is obtained. When the silicon nanosheets obtained in the present invention are used for visible light photocatalytic hydrogen production, the hydrogen production efficiency can reach 5.102 mmol h ‑1 g ‑1 , the photocatalytic hydrogen production efficiency is about 93 times higher than that of the original crystalline silicon powder. The method for preparing silicon nanosheets disclosed by the invention is simple to operate, low in cost, and can be prepared in large quantities, and the obtained silicon nanosheets have excellent visible-light photocatalytic hydrogen production performance, providing a new method for building stable and efficient photolysis of water for hydrogen production materials. train of thought.

Description

technical field [0001] The invention belongs to the field of nano-semiconductor photocatalysis, and in particular relates to a method for preparing an ultra-thin silicon nanosheet photocatalyst. Background technique [0002] Since the 21st century, the energy crisis and environmental pollution problems faced by mankind have become increasingly serious. Finding efficient and clean renewable energy is the only way for the sustainable development of human society. Among many new energy sources, hydrogen, which has many advantages such as cleanness, high efficiency, storage and transportation, is the most ideal green energy to replace traditional energy such as coal. Therefore, as a promising hydrogen production method, photocatalytic hydrogen production has been highly valued by countries all over the world. With the efforts of researchers, TiO has been discovered 2 , CdS, ZnO and a series of photocatalyst materials with excellent performance. But TiO 2 , ZnO and other wide...

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Problems solved by technology

[0004] At present, the methods for preparing silicon nanosheets include chemical vapor deposition, graphene oxide template method, magnesia thermal reduction method and silicide exfoliation method, but these methods still have many deficiencies, such as: chemical vapor deposition method is high in cost and low in output. It is suitable for large-scale production; the graphene oxide template method and magnesia thermal reduction method not only have complicated process flow, but also introduce impurities and structural defects that are difficult to completely remove, which will affect the performance of silicon nanosheets; the silicide exfoliation method needs to prepare CaSi 2 Layered precursors, the precursors are stripped into flakes and then reduced to silicon nanosheets. The process is complicated, the output is small, and the obtained silicon nanosheets are easily oxidized

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