Integrative Ni₁-P_x Catalytic Pairs for Low-Concentration CO₂ Electroreduction

The electrochemical CO₂ reduction reaction (CO₂RR) powered by renewable electricity offers a promising approach for sustainable carbon utilization. However, under industrially relevant low CO₂ concentrations (5-15 vol.%), the efficiency and selectivity of electrochemical CO₂RR are significantly constrained by the limited CO₂ supply and the competitive hydrogen evolution reaction (HER). Herein, we report integrative Ni₁-P_x catalytic pairs (Ni₁-P_x/ICPs) that exhibit super CO₂-to-CO conversion efficiency under low-concentration CO₂ conditions. In situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and X-ray absorption spectroscopy (XAS) measurements show that P incorporation modulates the electrochemical microenvironment and accelerates reaction kinetics. H/D isotopic substitution experiments and theoretical calculations unveil a mechanistic transition from an Eley-Rideal to Langmuir-Hinshelwood pathway, enabled by cooperative adsorption on adjacent Ni and P sites. Notably, a hydrogen-bonded six-membered Ni-C-O-H-O-P-Ni ring forms between adsorbed CO₂ and H₂O, facilitating proton-coupled electron transfer and lowering the reaction barrier. This unique adsorption motif enhances CO₂ activation, suppresses HER, and enables efficient CO generation at low CO₂ concentrations. Our findings show the importance of atomically dispersed catalytic pairs for advancing carbon utilization and overcoming selectivity challenges in electrochemical hydrogenation.