Accurately regulating the Ni coordination environment via atomic layer deposition and enabling the efficient CO2 electroreduction

Abstract

Atomically dispersed transition metal-anchored nitrogen-doped carbon (M-N-C) catalysts demonstrate exceptional performance in electrocatalytic CO2 reduction reaction (CO2RR), yet such default single-atom catalysts still encounter huge challenges due to the limited single-site catalytic capacity and high reaction energy barriers. Herein, we report an accurate regulation strategy for fabricating high-performance and robust xNi@NC-400H catalysts (x represents the cycles of deposition, H stands for H2) by combining mild atomic layer deposition (ALD) and reduction post-treatment for promising CO2RR. Notably, the 5Ni@NC-400H with abundant dual-atomic Ni2N6 sites exhibits a CO Faradaic efficiency (FECO) reaching 99.5% at -0.77 V vs. reversible hydrogen electrode (RHE) and maintains over 99% across a broad potential range from -0.37 to -1.17 V vs. RHE in flow cell, and also exhibiting excellent long-term stability. In-situ attenuated total reflection surfaceenhanced infrared absorption spectroscopy (ATR-SEIRAS) and density functional theory (DFT) calculations reveal the bridge adsorption of reaction intermediates at dual-atomic Ni2N6 site in 5Ni@NC-400H catalyst, which has a higher electron cloud density and lower activation energy barrier than that of 1Ni@NC-400H catalyst with linear adsorption at single-atom NiN4 site, thus significantly enhancing the CO2 activation ability.