Atom by atom: Enhancing CO2 electrolysis efficiency with Ni-NC catalysts using a simplified strategy

The search for low-carbon strategies to convert CO₂ into fuels and value-added chemicals has stimulated extensive research efforts. Single-atom catalysts (SACs) have emerged as promising electrocatalysts, as atomically dispersed active sites maximize faradaic efficiency (FE). In this study, we report the synthesis of Ni-phthalocyanine (NiPc) catalysts on carbon supports, further developed into a Ni single-atom catalyst (Ni–NC) featuring four nitrogen coordination sites. Comprehensive characterization using STEM, TEM, XPS, and XAS confirms the structural integrity and atomic dispersion of the active sites. Electrochemical evaluation demonstrates that Ni–NC achieves a high % CO faradaic efficiency of 67 %, with suppressed hydrogen evolution (28 %), underscoring its effectiveness in CO₂ reduction reactions (CO₂RR). Moreover, Ni–NC delivers a superior current density of 12 mA cm⁻², significantly outperforming NiPc. Density functional theory (DFT) calculations reveal that pyridinic nitrogen coordination optimises the binding energy of key reaction intermediates, thereby enhancing the production of CO. This mechanistic insight is further supported by in situ ATR-FTIR analysis. Collectively, these results establish Ni–NC as a highly efficient and selective catalyst for CO₂RR, offering a promising pathway toward improved carbon utilization and sustainable energy conversion. The MEA electrolyzer testing reaches the maximum of 85 % FE toward CO by applying 500 mA current for 20 h that realise the feasibility of this molecular catalyst rational transformative.