Preparation and enhanced photoelectrochemical performance of selenite-sensitized zinc oxide core/shell composite structure

Abstract

A fast, versatile and low-cost hydrothermal chemical synthesis based on ion-exchange has been used to deposit a shell of cupric selenite onto vertically aligned zinc oxide nanorod arrays with a buffer layer of zinc selenite for photoelectrochemical water splitting. In the present work, detailed growth mechanisms for single shell of zinc selenite composite structure and double shells of zinc selenite and cupric selenite closed nanotubes based on zinc oxide core are discussed. The enhanced optical property and the improved photoelectrochemical performance are characterized. On the basis of cupric selenite outer shell, such a novel core/shell nanostructure provides a high photocatalytic activity, and the photocurrent density is up to 5.70 mA cm⁻². This promising result is probably due to the improved absorption efficiency, enhanced photoelectron collection process and reduced recombination rate including photoelectron injection and charge transportation. The double shells based on zinc oxide composite structure can render this new material promising in photoelectrochemical water splitting.