Surface Modification And Photoelectrochemical Performance Study Of Bismuth Vanadate

With the increase of population,people pay more attention to the future energy and environmental crisis.It is very important to explore sustainable and eco-friendly new energy.To realize the conversion of solar energy to chemical energy is an important technology to solve the energy crisis and environmental pollution problems.With the unremitting efforts of scientific researchers,great progress has been made,such as hydrogen production by water decomposition and ammonia production by nitrogen reduction.The appropriate semiconductor are the key factors of these technical properties.Bismuth vanadate（BiVO₄）has been widely used because of its excellent properties,such as the excellent ability of photo-response,suitable band edge position,low toxicity,low cost,and abundant reserves.However,its performance is limited by slow dynamics and high electron-hole recombination rate.At present,the modification of BiVO₄ has been deeply studied,and heterojunction structure,element doping,crystal plane control and other methods have been proposed.According to the previous research,three methods of BiVO₄ modification were explored in this project.The morphologies and PEC properties of BiVO₄ were systematically analyzed.The details are as follows:（1）BiVO₄/Co_1-xS photoelectrode was successfully synthesized by simple successive ion layer adsorption/reaction（SILAR）,and applied to the PEC water splitting.In this system,the morphology,and elements of BiVO₄/Co_1-xS were analyzed to confirm the successful preparation of the photoelectrode firstly.Then,the properties of Photoelectrochemical impedance（PEIS）,Mott-Schottky（M-S）,Linear sweep voltammetry（LSV）and Applied bias photon-to-current efficiency（ABPE）were analyzed and studied.Finally,the influence of the load amount of Co_1-xS nanoparticles on the performance was studied.（2）Zn-MOF was loaded on the surface of BiVO₄ by soaking method,and the BiVO₄/Zn-MOF photoelectrode was studied by Scanning electron microscope（SEM）,X-ray photoelectron spectrometer（XPS）and Fourier Transform infrared spectroscopy（FTIR）characterization.At the same time,we analyzed the data of Linear sweep voltammetry（LSV）,stability,charge injection and separation efficiency,and proved that Zn-MOF plays an important role in improving the PEC properties of BiVO₄.（3）BiVO₄/MnCO₃/C was prepared by a one-step hydrothermal method.The successful synthesis of the photoelectrode was preliminarily characterized.The electrode was applied to the NRR system,and the performance of N₂ programmed desorption（N₂-TPD）,LSV,¹⁵N₂ isotope tracing were studied.This work confirmed that the amorphous MnCO₃/C film could effectively improve the carrier transport speed and reduce the recombination efficiency of electron and hole.Finally,the mechanism of BiVO₄/MnCO₃/C in NRR was discussed.