Boosting promote C₂ products formation in electrochemical CO₂ reduction reaction via phosphorus-enhanced proton feeding

Electrochemical CO₂ reduction reaction (CO₂RR) using renewable energy to produce valuable multicarbon (C₂₊) products is a promising approach for carbon emission reduction. In this work, we propose a new strategy to enhance the formation of hydrogen-containing intermediates using the excellent abilities of proton transportation and electronic structure modification of phosphorus (P). To realize this, an in situ electrodeposition method was proposed to prepare P-doped Cu catalysts. It was found that the electrodeposition potential significantly impacts the structure and catalytic performance of P-Cu catalysts. Specifically, the catalyst obtained at − 0.5 V vs. Ag/AgCl exhibited exceptional performance for CO₂RR towards C₂₊ products, achieving a Faradaic efficiency (FE) of ∼ 80.2 % and a partial current density of 40.4 mA cm⁻² in an H-type cell. Furthermore, the catalyst demonstrated stability for at least 12 h. Experimental and density functional theory (DFT) studies revealed that the free energy of the hydrogenated process could be significantly reduced by the excellent proton transport ability of P, and the interaction of Cu with the unpaired electrons of carbon could be improved, leading to excellent adsorption ability of Cu for the intermediates and high FE of C₂₊ products.