Highly Ethylene-Selective Electroreduction CO2 Over Cu Phosphate Nanostructures with Tunable Morphology

Highly selective production of valuable ethylene from electrocatalytic CO2 reduction reaction (ECO2RR) is particularly desirable yet challenging. Morphology engineering is an effective strategy for catalyst design, which can adjust the electronic structure of catalyst surface, change the adsorption behavior of critical reaction intermediates over catalyst surface, and thus regulate the activity of electrocatalytic CO2 reduction reaction. In this work, we prepared copper phosphate catalysts with different morphologies and tested their catalytic activity for the ECO2RR in the flow cell. Compared with irregular flocculent aggregates, copper phosphate nanospheres exhibit a high and stable ethylene Faradaic efficiency of 47% with high current density of 350 mA middotcm(- 2), which is higher than the 200 mA middotcm(- 2) required for industrial applications. The catalysts were extensively characterized by SEM, EDS, XRD, ICP-OES, XPS, BET and CO-TPD. Combining the characterization results and activity data, we found that the superior spherical morphology of copper phosphate can increase the electron density around Cu, stabilize the Cu+ species on the surface through the electron transfer between P and Cu, and adjust the adsorption strength of CO intermediates (*CO) to enhance the productivity of C2+ products. This work provides new insights into catalyst design for highly efficient C2H4 production from the electrocatalytic CO2 reduction reaction by tuning morphologies of Cu-based catalysts.