<i>N</i>-Heterocyclic Carbene Polymer-Stabilized Au Nanowires for Selective and Stable Reduction of CO<sub>2</sub>
Yuliang Chen, Kecheng Wei, Hanyi Duan, Haobo Sun, Yu Zhang, Ahsan Zohaib, Pengcheng Zhu, Jie He, Shouheng Sun
Abstract
The structural stability of nanocatalysts during electrochemical CO 2 reduction (CO 2 RR) is crucial for practical applications. However, highly active nanocatalysts often reconstruct under reductive conditions, requiring stabilization strategies to maintain activity. Here, we demonstrate that the N -heterocyclic carbene (NHC) polymer stabilizes Au nanowire (NW) catalysts for selective CO 2 reduction to CO over a broad potential range, enabling coupling with Cu NWs for one-step tandem conversion of CO 2 to C 2 H 4 . By combining the hydrophobicity of the polystyrene chain and the strong binding of NHC to Au, the polymer stabilizes Au NWs and promotes CO 2 RR to CO with excellent selectivity (>90%) across −0.4 V to −1.0 V (vs RHE), a significantly broader range than unmodified Au NWs (−0.5 V to −0.7 V). Stable CO 2 RR at negative potentials yields a high j CO of 142 A/g Au at −1.0 V. In situ ATR-IR analysis indicates that the NHC polymer regulates the water microenvironment and suppresses hydrogen evolution at high overpotential. Moreover, NHC-Au NWs maintain excellent stability during 10 h of CO 2 RR testing, preserving the NW morphology and catalytic performance, while unmodified NWs degrade into nanoparticles with reduced activity and selectivity. NHC-Au NWs can be coupled with Cu NWs in a flow cell to catalyze CO 2 RR to C 2 H 4 with 58% efficiency and a partial current density of 70 mA/cm 2 (overall C 2 product efficiency of 65%). This study presents an adaptable strategy to enhance the catalyst microenvironment, ensure stability, and enable efficient tandem CO 2 conversion into value-added hydrocarbons.