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Bismuth‐based materials have emerged as promising catalysts in the electrocatalytic reduction of CO2 to formate. However, the reasons for the reconstruction of Bi‐based precursors to form bismuth nanosheets are still puzzling, especially the formation of defective bismuth sites. Herein, we prepare bismuth nanosheets with vacancy‐rich defects (V‐Bi NS) by rapidly reconstructing Bi19Cl3S27 under negative potential. Theoretical analysis reveals that the introduction of chlorine induces the generation of intrinsic electric field in the precursor, thereby increasing the electron transfer rate and further promoting the metallization of trivalent bismuth. Meanwhile, experimental tests verify that Bi19Cl3S27 has a faster reconstruction rate than Bi2S3. The formed V‐Bi NS exhibits up to 96 % HCOO− Faraday efficiency and 400 mA cm−2 HCOO− partial current densities, and its electrochemical active surface area normalized formate current density and yield are 2.2 times higher than those of intact bismuth nanosheets (I‐Bi NS). Density functional theory calculations indicate that bismuth vacancies with electron‐rich aggregation reduce the activation energy of CO2 to *CO2− radicals and stabilize the adsorption of the key intermediate *OCHO, thus facilitating the reaction kinetics of formate production. [ABSTRACT FROM AUTHOR]

The direct electrochemical nitric oxide reduction reaction (NORR) is an attractive technique for converting NO into NH3 with low power consumption under ambient conditions. Optimizing the electronic structure of the active sites can greatly improve the performance of electrocatalysts. Herein, we prepare body‐centered cubic RuGa intermetallic compounds (i.e. bcc RuGa IMCs) via a substrate‐anchored thermal annealing method. The electrocatalyst exhibits a remarkable NH4+ yield rate of 320.6 μmol h−1 mg−1Ru with the corresponding Faradaic efficiency of 72.3 % at very low potential of −0.2 V vs. reversible hydrogen electrode (RHE) in neutral media. Theoretical calculations reveal that the electron‐rich Ru atoms in bcc RuGa IMCs facilitate the adsorption and activation of *HNO intermediate. Hence, the energy barrier of the potential‐determining step in NORR could be greatly reduced. [ABSTRACT FROM AUTHOR]