Fabrication,Structure And Photocatalytic Water Splitting Properties Of Photoelectrochemical Cell Electrode Composites

Hydrogen is an ideal secondary energy,which is clean,efficient,safe and environmentally with high thermal energy concentration.Research and development of hydrogen is a promising way.Hydrogen production can be realized by photocatalytic water splitting,whose principle is to turn solar energy into chemical energy which can be stored and got readily.Photochemical cell is an effective mean to split water to produce hydrogen.This reasearch aims to study the compisition,preparation and measurement of photoelectrochemical cells-photoanode and photocathode materials.Photoanode is made of n-type semiconductor such as a-Fe2O3 with a small bandgap and ZnO with a large bandgap as the main catalytic material while photocathode is made of p-type semiconductor NiO as the main catalytic material.The photoelectric conversion efficiency and photocatalytic performance of catalysts are improved by doping,loading with other semiconductors and etc.,this reasearch provides new ideas for developing high-performance catalysts with sensitive response to solar-light and expanding the application of photochemical cells in the field of solar energy conversion.The main contents are summarized as follows:(1)Spindle-like Sn4+ doped a-Fe2O3 nanoparticles and Ca Mn2O4 nanowire was prepared by a hydrothermal method.Ca Mn2O4 modified Sn4+ doped a-Fe2O3 was prepared by low temperature mixing method.Results showed that the conductivity and the light absorption to solar energy of the catalyst have been enhanced by doping with Sn4+ and the response to solar energy achieved the best when the molar ratio of Sn4+ is 3%.Loading with Ca Mn2O4 can promote the electron-hole transfer,which is beneficial to improve the efficiency of photocatalytic reaction.When the amount of Ca Mn2O4 reaches 10%,the photocatalytic activity of the composite exhibited the best effect.The amount of oxygen produced by photocatalysis water oxidation is 2 ?mol under the irradiation of solar simulator for 2 h with the bias of 1 V vs.RHE.The study provides a new idea for the design of photoanode materials with two components of non-noble metal photocatalysts.(2)ZnO/In2O3 composite was prepared by a simple chemical precipitation and calcination methode and three-component nanocomposites consisted of Ca Mn2O4 and ZnO/In2O3 were synthesized by low temperature mixing reaction.The prepared samples were characterized by TEM,XPS and UV-vis absorption.The results showed that the size of the synthesized spherical ZnO was in the nano-scale,the incorporation of In3+ had almost no effect in the morphology of pristine ZnO.At the same time,the nanowire-shaped Ca Mn2O4 was successfully loaded on the surface of ZnO/In2O3 and the photocatalytic efficiency of water splitting was also improved.The oxygen produced from the composite photocatalysis water oxidation was 3.8 ?mol under the irradiation of UV-visible light simulator for 2 h at the voltage of 1 V vs.RHE.(3)Black NiO/Cu2O nanoparticles were synthesized by a low temperature solid state method.Results show that the size of the synthesized NiO is in the nanometer scale and the loading of Cu2O has almost no effect on the morphology of NiO,whereas the avtivity of photocatalytic water splitting for hydrogen evolution has been improved with less Cu2O.When the mass fraction of Cu2O reached 6%,the photocatalysis water splitting achieved the largest hydrogen yield of 17.6 ?mol under the irradiation of solar simulator for 2 h with the bias of-0.0455 V vs.RHE while pure NiO showed no hydrogen produce performance.