Copper (Cu)-based catalysts generally exhibit high C2+ selectivity during the electrochemical CO2 reduction reaction (CO2RR). However, the origin of this selectivity and the influence of catalyst precursors on it are not fully understood. We combine operando X-ray diffraction and operando Raman spectroscopy to monitor the structural and compositional evolution of three Cu precursors during the CO2RR. The results indicate that despite different kinetics, all three precursors are completely reduced to Cu(0) with similar grain sizes (~11 nm), and that oxidized Cu species are not involved in the CO2RR. Furthermore, Cu(OH)2- and Cu2(OH)2CO3-derived Cu exhibit considerable tensile strain (0.43%~0.55%), whereas CuO-derived Cu does not. Theoretical calculations suggest that the tensile strain in Cu lattice is conducive to promoting CO2RR, which is consistent with experimental observations. The high CO2RR performance of some derived Cu catalysts is attributed to the combined effect of the small grain size and lattice strain, both originating from the in situ electroreduction of precursors. These findings establish correlations between Cu precursors, lattice strains, and catalytic behaviors, demonstrating the unique ability of operando characterization in studying electrochemical processes.
Bibliographical noteFunding Information:
The financial support for this work was provided by KAUST Catalysis Center CCF Fund (FCC/1/1974-16-01) to Y.H. and Baseline Funds (BAS/1/1413-01-01) to X.L. from King Abdullah University of Science and Technology. This work is partially supported by National Key Research and Development Project of China (2022YFE0113800). This research used resources from the Core Laboratories of King Abdullah University of Science and Technology. J.Y. acknowledges financial support from the Hong Kong Polytechnic University (grant P0042930).
© 2022, The Author(s).
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)