Probing Individual Cuprous Oxide Microcrystals towards Carbon Dioxide Reduction by using In Situ Raman‐coupled Scanning Electrochemical Microscopy

Abstract

Abstract In this work, the simultaneous investigation of a single cuprous oxide microcrystal towards CO 2 electroreduction (CRR, CO 2 reduction reaction) by using Raman microscopy and scanning electrochemical microscopy (SECM) is shown. Cu 2 O microcrystals were electrochemically crystallized on an indium‐doped tin oxide‐substrate (ITO). Structural changes of the Cu 2 O 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 CO 2 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.