Preparing method for cobalt-phosphide-modified molybdenum-doped bismuth vanadate photoelectrode

Abstract

The invention discloses a preparing method for a cobalt-phosphide-modified molybdenum-doped bismuth vanadate photoelectrode. The preparing method includes the steps that a bismuth oxyiodide photoelectrode is made on the surface of conducting glass with the sedimentation method, a vanadium source solution and a molybdenum source solution are dropwise added onto the bismuth oxyiodide photoelectrode,annealing cleaning is carried out, and then molybdenum-doped bismuth vanadate photoelectrode is obtained; cobalt phosphide is subjected to electrodeposition on the surface of the molybdenum-doped bismuth vanadate photoelectrode through photo assisting in a three-electrode system, and the novel bismuth vanadate photoelectrode is obtained. The invention also discloses application of the composite molybdenum bismuth vanadate photoelectrode to photoelectrocatalysis decomposition of water. The photoelectrode prepared with the method is used for producing hydrogen through photoelectrocatalysis decomposition of water, and through molybdenum doping, the concentration of charge carriers can be effectively increased, and photocurrent is increased; through cobalt-phosphide electrodeposition, composite loss in the photoelectrode can be effectively delayed, the service life of photon-generated carriers is prolonged, an oxygen evolution reaction on the surface of the photoelectrode is promoted, andtherefore the solar energy photo-hydrogen conversion efficiency of the semiconductor photoelectrode is improved.

Description

technical field [0001] The invention belongs to the technical field of photoelectric materials, and in particular relates to a preparation method of a cobalt phosphide-modified molybdenum-doped bismuth vanadate photoelectrode and its application in photoelectric catalytic water decomposition. Background technique [0002] In order to realize the strategy of sustainable development, the development and utilization of renewable energy industry has become an important strategic goal of all countries in the world. Among them, solar energy, as a clean renewable energy source, has tens of thousands of times the reserves of other renewable energy sources; at the same time, solar energy hardly releases greenhouse gases during use, which helps to alleviate environmental pollution caused by extensive use of petroleum and fuel combustion. Environmental issues such as the greenhouse effect promoted by the solar energy have occupied an important position in the renewable energy industry....

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Problems solved by technology

The theoretical photolysis efficiency of bismuth vanadate is 9.2%, which is equivalent to a photocurrent density of 7.5mA cm -2 , but the actual photolysis efficiency of bismuth vanadate is much lower than its theoretical efficiency, and the current density of intrinsic bismuth vanadate photoelectrode is only 0.42mAcm -2 , as long as it is caused by the following three aspects: ① poor electron transport and high surface defects cause up to 60-80% charge recombination; ② slow oxygen evolution kinetics; ③ conduction band edge is slightly lower than the reversible hydrogen potential

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