Surface Modified Bismuth vanadate in Photoelectrochemical Splitting of Water

Abstract

In present scenario, world is focusing on substituting non-renewable fossil fuels with renewable energy reservoirs with the development of zero carbon emission fuel in order to meet the increasing energy demand. Hydrogen is considered to be a sustainable future fuel. Hydrogen can be produced from various methods but solar energy prompted photoelectrochemical (PEC) water splitting via light gripping semiconductor material originates as a golden methodology as it can accomplish the global energy constrains. The challenge is to develop an appropriate semiconductor material for efficient water splitting. newlinePresent study mainly focuses on BiVO4, Fe2O3, ZnFe2O4 semiconductor metal oxide. Various types of modifications have been applied on pristine as well as modified metal oxide which results in enhancement in photoelectrochemical response. Doping of Ni in BiVO4 was done to examine the PEC performance in phosphate buffer electrolyte and enhanced response was observed due to enhanced electrical conductivity as well as separation of photogenerated charge carriers. The role of MWCNTs as electron conducting pathway in Ni:BiVO4 was also studied. This increment in PEC performance was observed due to the increased carrier concentration and creation of a conducting pathway for the transference of photogenerated charge carriers. Zr:W co-doping effect on the PEC performance of BiVO4 was investigated which showed improved photoelectrochemical properties. Triple heterojunction Zr:W-BiVO4/Fe2O3/ZnFe2O4 were synthesized and proper band edge positions facilitated enhanced PEC activity.. newlineThe BiVO4, Fe2O3 and ZnFe2O4 thin films were prepared using Electrodeposition and Spray Pyrolysis method. The synthesized films were then characterized by XRD, SEM, EDAX, UV-Visible spectroscopy, Raman and XPS. The electrochemical and photoelectrochemical studies were performed which includes measurement of current voltage (I-V) characteristics, open circuit potential etc. Mott-Schottky analysis provide the value of flat band potential while charge transfer resistance of the thin films was analyzed from the Nyquist plots. Efficiency of the prepared system was examined through applied bias photon to current conversion efficiency (ABPE), charge injection and carrier separation efficiency using hole scavenger. newline newline