Influence of Fermi-Level Engineering in Multi-Interface CuO/Cu2o||Rgo||H-WO3||Rgo|| Photoelectrodes on Photoelectrochemical CO2 Reduction

Abstract

Novel materials, architectures, geometries are crucial for achieving the progress in science in general. Therefore, heterojunction engineering, which enables more versatile and higher performance systems than single components, has emerged as a means of tailoring the optoelectronic properties of photoelectrodes. However, constructing effective and stable hybrid semiconductor heterojunctions is a challenging task under the strict requirements of band alignment, vacancy characteristics, and interface properties. In this presentation, we will demonstrate the enhancement of photoelectrochemical (PEC) reduction of CO2 to methanol, by a novel approach relying on modeling the Fermi level in a multi-interface architecture. The excellent PEC CO2 reduction activity has been attributed to the formation of a high-performance, energetically aligned multi-interface system of CuO/Cu2O||rGO|h-WO3|rGO (rGO = reduced graphene oxide layer). The overall performance of this hybrid system strongly depended on the number of oxygen groups in rGO and the structural properties of rGO. Furthermore, to construct an effective PEC system, numerous postsynthetic treatments were explored for their practicality and usefulness. The results presented herein clearly showed that the best performance toward the CO2 photoreduction currents of 3 mA/cm2 at 0.00.1 V versus RHE (more than double that of the CuO/Cu2O system) had been reached for the semiconductor architecture containing two inter-layers of rGO. The role of those layers in the overall system performance will be an objective of the presentation.