Nanostructured Î-MnO2/Cd(OH)2Heterojunction Constructed under Ambient Conditions as a Sustainable Cathode for Photocatalytic Hydrogen Production

Abstract

In this study, we report the deposition of a thin layer of Cd(OH)2 over Î-MnO2 deposited on a fluorine-doped tin oxide (FTO) glass substrate, thereby forming a heterojunction with synergistic effects. Electrodes fabricated by a room-temperature, facile, and cost-effective chemical bath deposition method display enhanced photoactivity when used as cathodes for the hydrogen evolution reaction (HER) in a photoelectrochemical cell, with an observed photocurrent of 0.3 mA/cm2 at 0 V vs reversible hydrogen electrode (RHE). The electrodes also showcase a dark electrocatalytic current of 2.9 mA/cm2 without illumination. The Î-MnO2/Cd(OH)2 nano-heterostructure is analyzed thoroughly via various physicochemical, optical and electrochemical methods to understand the phenomena involved in the conduction characteristics. The enhanced photoconductivity is attributed to effective charge separation and transport by the presence of synergistic materials with optimal band gap energies. These results show promise for the use of birnessite-based materials as sustainable electro-or photocatalysts for the hydrogen evolution reaction. Copyright © 2020 American Chemical Society.