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

Electrochemical carbon dioxide (CO 2 ) reduction reaction (CO 2 RR) to obtain C2/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 C2/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 C2 selectivity with a Faradaic efficiency (FE C2 ) of 57.22% at −1.3 V ( vs . RHE), which is about 2.5-fold than the C-Cu (FE C2 of 22.71%). This work provides an effective strategy to improve the activity and selectivity of C2 products in CO 2 RR by optimizing the adsorption/enrichment property of intermediates.