In situ grown complex metal oxide heterostructures for efficient oxygen evolution and hydrogen evolution reactions

Abstract

The present thesis primarily focused on design and development of in-situ grown metal oxide-based catalysts for efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, metal oxide semiconductors such as CuBi2O4 and BiVO4 were used as a model system to carry out photoelectrochemical water splitting, while MnCo2O4 was used as an electrocatalyst to perform electrocatalytic water splitting. The formation of heterojunction using a co-catalyst, elemental doping, hole/electron extractor catalyst, and morphological changes are a few techniques that were tried on the metal oxide semiconductors to enhance their water-splitting efficiency. In the synthesis of the catalyst, importance was given to their direct growth over the substrate, which allows efficient transfer/ injection of charge carriers at the interface of the semiconductor and the substrate. In the current thesis, priority was given for the fabrication of working electrodes that are environment-friendly and cost-effective, along with developing them through a simple synthetic protocol. This thesis is arranged as follows: firstly, the introduction is given on the global energy consumption and environmental challenges, need for a sustainable energy source to produce zero-emission H2/O2 gas...