Oxide-based nanostructures for photocatalytic and electrocatalytic applications

Abstract

Diminishing fossil fuels and global warming issues have forced the scientists to look for alternative sources of energy to cater to the ever increasing demand. Artificial systems are being developed in order to mimic natural photosynthesis and directly harvest and convert solar energy into renewable energy and environmental remediation. Despite significant efforts, it has not been possible to design a single material which has sufficient efficiency, stability and low cost. To integrate the desired characteristics into a single component, heterogeneous photocatalysts are designed with multiple functional components which could combine the advantages of different components to overcome the drawbacks of single component photocatalysts. The present highlight gives a concise overview of heterogeneous catalysts that have been developed and studied in our group and some excellent works of others in recent years. The review focuses on the principles of photocatalytic and electrocatalytic activities followed by some key examples of oxide-based materials. This includes a wide range of structural modification and crystal growth processes leading to composites, heterostructures, including insulator/semiconductor, semiconductor/semiconductor, and multi-heteronanostructures, and core–shell nanostructures which have been modified in order to improve the performance by increasing the light absorption, promoting the charge separation and transportation, and enhancing the redox catalytic activity and intrinsic electrocatalytic properties. The electrochemical processes like hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) have been discussed closely on the effects of size, shape, exposed facets and surface area of electrocatalysts (metal oxides).