Intermediate enrichment effect of porous Cu catalyst for CO2 electroreduction to C2 fuels

Electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) to obtain C-2/multi-carbon fuels is an appealing technology to reduce carbon emission and store intermittent renewable electricity. The C-C coupling process, as the most critical step for generating C-2/multi-carbon fuels, strongly depends on the concentration of *CO intermediates around the active sites. In this work, we prepared porous copper nanospheres (P-Cu) that greatly improved the C-C coupling process by enriching *CO intermediates in the pore structure. The specific pore features of P-Cu were characterized in detail by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption/desorption tests. Obviously, the P-Cu exhibits higher specific surface area and richer pore structure than the control sample compact copper nanosphere (C-Cu). The CO gas sensor and temperature programmed desorption (TPD) tests prove that the P-Cu has better CO adsorption and enrichment capacity than C-Cu due to the rich pore structure. As a result, P-Cu exhibited a high C-2 selectivity with a Faradaic efficiency (FEC2) of 57.22% at-1.3 V ( vs . RHE), which is about 2.5-fold than the C-Cu (FEC2 of 22.71%). This work provides an effective strategy to improve the activity and selectivity of C-2 products in CO2RR by optimizing the adsorption/enrichment property of intermediates. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study improved the efficiency of electrochemical carbon dioxide reduction reaction by preparing porous copper nanospheres, which enhanced the C-C coupling process and led to higher C-2 selectivity. The porous copper nanosphere exhibited richer pore structure, which facilitated better CO adsorption and enrichment, resulting in improved selectivity and Faradaic efficiency of the products.