Graphene-Silver Tungstate Composite Photocatalyst

Photocatalysis is a new science. It uses semiconductor photocatalytic materials to obtain cheap and sustainable solar energy from nature, reduce the cost of hydrogen production and decompose various organic pollutants. It has a good application prospect in solving energy crisis and environmental pollution control.

The photocatalytic properties of semiconductors have been confirmed by many studies, but from the point of view of catalytic efficiency, there are still many problems restricting the wide application of this technology. How to improve the quantum efficiency of photocatalyst so that it can be accepted economically is one of the research focuses in the field of photocatalysis.

Silver tungstate nanorods in graphene-silver tungstate composites are not simply attached to the surface of graphene sheets, but encapsulated by graphene sheets, which can not only prevent the oxidation of silver tungstate, but also increase the specific surface area of photocatalyst, and play a role in the degradation of pollutants. Its preparation follows the following steps:

(1)Graphene oxide was dissolved in deionized water for 3-5 hours, and the dispersed solution was obtained.

(2)Silver nitrate was added into the graphene oxide dispersions, and the mixed solution was obtained by adding sodium tungstate solution dropwise after stirring uniformly.

(3)The obtained mixed solution is transferred to the PTFE inner gallbladder. The inner gallbladder is placed in the stainless steel jacket. After sealing, the reactor will naturally cool to room temperature after 12-24 hours reaction at 140-200 ℃.

(4)The product was separated by centrifugation, then washed with distilled water and absolute ethanol, and dried in vacuum to obtain graphene-silver tungstate composite photocatalytic material.

Graphene-silver tungstate composite photocatalytic material is green and environmental friendly. The preparation process is simple and the raw materials are easy to obtain. Compared with the traditional single silver tungstate photocatalyst, the composite photocatalyst can give full play to the synergistic advantages of silver tungstate and graphene, promote the separation of photogenerated charges, broaden the range of photoresponse of silver tungstate catalyst, improve the catalytic stability of silver tungstate, and is conducive to the recovery and utilization of silver tungstate, and reduce the cost. The prepared graphene-silver tungstate visible-light photocatalyst can effectively adsorb and photocatalytically degrade organic dyes and toxic and harmful pollutants without causing secondary pollution. It has important application value in environmental protection, functional composite materials and other fields.

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