Photoelectrochemical hydrogen evolution from water on a surface modified CdTe thin film electrode under simulated sunlight

Abstract

Photoelectrochemical hydrogen evolution from water using CdTe photocathodes prepared by close spaced sublimation was investigated. A CdTe thin film deposited on a fluorine-doped tin oxide-coated (FTO) glass plate acted as the photocathode. Surface modification of this photocathode with Pt resulted in an increase in the cathodic photocurrent from only 0.01 to 0.14 mA cm⁻² at 0.1 V_RHE. Further surface modification with an approximately 80 nm-thick CdS layer dramatically increased both the cathodic photocurrent and the onset potential, from 0.14 to 6.0 mA cm⁻² at 0.1 V_RHE and from 0.2 to 0.6 V_RHE, respectively, under simulated sunlight. The CdTe photocathode showed stoichiometric hydrogen evolution from water, with a half-cell solar to hydrogen conversion efficiency of 0.9% at approximately 0.2 V_RHE.