Surface Molecular Functionalization of Unusual Phase Metal Nanomaterials for Highly Efficient Electrochemical Carbon Dioxide Reduction under Industry‐Relevant Current Density

The electrochemical carbon dioxide reduction reaction (CO 2 RR) provides a sustainable strategy to relieve global warming and achieve carbon neutrality. However, the practical application of CO 2 RR is still limited by the poor selectivity and low current density. Here, the surface molecular functionalization of unusual phase metal nanomaterials for high‐performance CO 2 RR under industry‐relevant current density is reported. It is observed that 5‐mercapto‐1‐methyltetrazole (MMT)‐modified 4H/face‐centered cubic (fcc) gold (Au) nanorods demonstrate greatly enhanced CO 2 RR performance than original oleylamine (OAm)‐capped 4H/fcc Au nanorods in both an H‐type cell and flow cell. Significantly, MMT‐modified 4H/fcc Au nanorods deliver an excellent carbon monoxide selectivity of 95.6% under the industry‐relevant current density of 200 mA cm −2 . Density functional theory calculations reveal distinct electronic modulations by surface ligands, in which MMT improves while OAm suppresses the surface electroactivity of 4H/fcc Au nanorods. Furthermore, this method can be extended to various MMT derivatives and conventional fcc Au nanostructures in boosting CO 2 RR performance.