Preparation Of Tantalum And Niobium-based Photoelectrodes And Study On The Photoelectric Properties Of Modified Tantalum-based Photoelectrodes

With the development of society,the problem of energy crisis is becoming more and more serious in recent years.Therefore,using solar energy to produce hydrogen by photoelectric chemical decomposition of water has become an important way to alleviate the energy crisis.The use of hydrogen energy has greatly alleviated the global energy shortage and environmental pollution problems.Ta and Nb,as the same main group,have ideal valence band position and good photoelectric response ability,so they are ideal materials for preparing photoelectrode.However,due to the carrier separation efficiency is low,easy to be affected by photocorrosion,poor stability and other factors,its practical application still has many limitations.The electrochemical anodic oxidation method takes pure Nb and Ta foil as the substrate,and carries out the in-situ self-growth reaction under the applied voltage.By adjusting the oxidation voltage,oxidation time,electrolyte concentration,boosting method and other influencing factors,it is finally realized.The controlled growth of Nb₂O₅ thin film and Ta₂O₅nanotubes,the best condition samples are:Nb₂O₅ NTs_{（0.8-30-30）}with a pore size of 110nm and a film thickness of 10μm;Ta₂O₅ NTs_{（15V/3s,60V-1h）}tube The diameter is about 100-120nm,and the tube length is 15μm.The Ta₂O₅ nanotubes with the best morphology are used as the precursor to prepare Ta₃N₅NTs.By controlling the nitriding temperature and nitriding time and other influencing factors in the nitriding process,the conversion of Ta₂O₅ to Ta₃N₅ is carried out more thoroughly,thereby making Ta₃N₅ Can be highly crystallized.A heterojunction system is formed by loading Co₃O₄and Ta₃N₅,and the surface layer of Ta₃N₅ NTs is modified by loading a hydrated iron oxide layer.The hydrated iron oxide layer is used as a"hole storage layer",which can quickly capture and capture light-generated holes.Storage improves the carrier separation efficiency of Ta₃N₅NTs,reduces the recombination probability of photo-generated hole-electron pairs,and greatly improves the stability of Ta₃N₅ NTs.Through the synergistic modification of Fe-Co,the photocurrent density of Ta₃N₅ NTs reaches 5.1 m A·cm^-2,which is about 4.3 times higher than that of Ta₃N₅ NTs;its stability is increased by about 85%.