P-tuned FeN2 binuclear sites for boosted CO2 electro-reduction

The recycling of CO₂ through electrochemical processes offers a promising solution for alleviating the greenhouse effect; however, the activation of CO₂ and desorption of *CO in electrocatalytic CO₂ reduction (ECR) frequently encounter high energy barriers and competitive hydrogen evolution reactions (HERs), which are urgent problems that need to be addressed. In this study, a catalyst (P₁₀₀–Fe–N/C) with homogeneous P–tuned FeN₂ binuclear sites (N₂PFe-FePN₂) was successfully synthesised, demonstrating satisfactory performance in the ECR to CO. P₁₀₀–Fe–N/C attains a peak FE_CO of 98.01% and a normalized TOF of 664.7 h⁻¹ at −0.7 V_RHE, surpassing the performance of the Fe binuclear catalyst without P and single-atoms catalysts. In the MEA cell, a FE_CO exceeding 90% can still be achieved. Density functional theory analysis indicates that the asymmetric coordination configuration induced by the incorporation of P facilitates a reduction in the system’s energy. The modulation of P results in the d-band centre of the catalyst being positioned closer to the Fermi level, which facilitates the interaction of the catalyst with CO₂, allowing more electrons to be injected into the CO₂ molecule at the Fe binuclear sites and inhibiting the HER. The P–tuned FeN₂ binuclear sites effectively lower the *CO desorption barrier.