| With the rapidly development of industry,the deterioration of the environment and the depletion of fossil energy have become two major problems that mankind urgently needs to solve.Solar energy has the advantages of abundant stock,cleanliness and environmental protection,etc.Therefore,it has become a research hotspot in the world for how to effectively use solar energy.Photoelectrochemical（PEC）decomposition of water is the use of thin-film electrodes to collect solar energy and generate electrons and holes to generate H2 and O2 on the surface of the cathode and anode,respectively,and is considered to be one of the important means for converting solar energy into chemical energy.Demand for clean and sustainable energy supplies.In a PEC system,the anode is a key component that determines system performance.Therefore,exploring high-performance photoanode materials has become one of the most important topics in PEC research.The ideal water-dissipating semiconductor photoanode material must have a suitable energy band structure,and its conduction band valence band position must meet the requirements of water reduction and oxidation potential,in addition to having good carrier transport efficiency and light absorption range and good stability in the liquid.Since the pioneering work of Boddy and Fujishima on TiO2,people have made great efforts to find new electrode structures（such as heterojunction or composite films）and new materials with high catalytic efficiency,despite a great deal of research work.However,finding the material to meet all these requirements is difficult.Therefore,the improvement of the properties of existing photoelectrode materials and the exploration of promising new materials for photoanodes have become the two main directions of current research.In this dissertation,for the purpose of developing new materials for photoanode and improving the properties of existing photoanode materials,the multi-metal oxides lead(Pb3Nb4O13)and bismuth molybdate（Bi2MoO6）with visible light response were selected as the object of study for the photoelectrochemical decomposition of water.The principle and the main way to improve the photo-anode photoelectrochemical performance is the starting point,and the photoelectrochemical activity of Pb3Nb4O13photoanode was studied.The photoelectrochemical activity of the Pb3Nb4O13photoanode was improved by optimizing the film formation conditions,sample post-treatment,electrode electron transport characteristics,and electrode surface modification.At the same time,aiming at the deficiency of Bi2MoO6,the preparation method was improved according to the characteristics of the material itself,and the quantum conversion efficiency was significantly improved.The specific work is as follows:1.Preparation and Photoelectrochemical Properties of Pb3Nb4O13 Photoanode.Firstly,Pb3Nb4O13 powder was prepared by two-step solid-phase synthesis method.The photoanode thin film was successfully prepared on conductive glass（FTO）by electrophoretic deposition method,and TiCl4 was used as the electrical connecting agent.Through X-ray diffraction（XRD）,scanning electron microscopy（SEM）,Mott-Schottky curve test,and a series of electrochemical tests,the film thickness,temperature,and subsequent surface loading of Co-Pi were investigated.The formation process,phase,morphology and photoelectrochemical properties of the samples were analyzed,and the formation mechanism was discussed.After the film was treated with TiCl4 electrical connector,the photoelectrochemical performance of the photoanode was improved.After Co-Pi loading on Pb3Nb4O13photoanode surface,the sample showed better photoelectrochemical performance.The surface modified Pb3Nb4O13 photoanode produced a photocurrent density of nearly 46.5μA/cm2 under xenon illumination,which was increased by nearly 18times.Under the irradiation of monochromatic light of 390 nm,the quantum conversion efficiency of the sample also increased from 0.08%to 0.22%.2.Preparation of compact Bi2MoO6 photoanode films for improved photoelectrochemical performance.A dense Bi2MoO6 photoanode film was prepared by a two-step film formation method.Before the preparation of Bi2MoO6 photoanode film by electrodeposition,a layer of thin film was coated on the conductive glass substrate by magnetron sputtering,and after annealing at high temperature,a highly crystalline Bi2MoO6photoanode film was formed.Compared with the Bi2MoO6 photoanode film that was not introduced into the substrate layer,the electrode film prepared by the two-step film formation method has high crystallinity,good photoelectrochemical performance,maximum photocurrent of 1.3 mA/cm2,and improved quantum conversion efficiency（IPCE）24 times,this can be attributed to the improved carrier transport observed with electrochemical impedance spectroscopy. |
