Probing individual cuprous oxide microcrystals towards carbon dioxide reduction by using In Situ raman-coupled scanning electrochemical microscopy

Abstract

In this work, the simultaneous investigation of a single cuprous oxide microcrystal towards CO2 electroreduction (CRR, CO2 reduction reaction) by using Raman microscopy and scanning electrochemical microscopy (SECM) is shown. Cu2O microcrystals were electrochemically crystallized on an indium-doped tin oxide-substrate (ITO). Structural changes of the Cu2O microcrystal are observed in situ by Raman microcopy, which indicates their fast conversion into elemental Cu at low overpotentials. Simultaneously, detection of products of the CO2 reduction is carried out electrochemically using the sample-generation tip-collection mode (SG/TC) of SECM and formate ions are the main product of CRR, as detected by a 10 μm Pt ultramicroelectrode (UME). Thus, with our approach, the very beginning of the CRR (onset potential), potential-dependent product formation as well as structural changes in the catalyst can be precisely investigated.