Development of high-density single atoms site (SAs) electrocatalysts is highly desirable due to their extraordinary catalytic performance. However, their synthesis is still challenging and their anticorrosion capacities in electrolyte (particularly in acidic electrolyte) are unsatisfying. Herein, we have constructed N,S co-doped carbon to anchor ~ 10 wt.% Co SAs (Co-SAs/NSC) via a novel polymerization–sulfurization–pyrolysis strategy toward selective electro-oxidation of thioethers in acidic solution. The as-obtained Co SAs has a coordination geometry of Co-S₂N₄, exhibiting excellent electrocatalytic activity and robust stability. At a low potential of 1.40 V vs. reversible hydrogen electrode (RHE), the conversion rate of thioethers over Co-SAs/NSC reaches 99.7% with 100% selectivity and 100% Faraday efficiency (FE) for producing sulfoxide, which is higher than the commercial Pt electrode and the reported state-of-the-art catalysts. Theoretical calculations and experiments reveal that the Co-S₂N₄ structure endows the outstanding electro-oxidation activity of Co SAs through significantly promoting desorption of the products. This work presents a convenient strategy to build high-performance SAs catalysts for the resourceful use of sulfur-containing pollutants.

The nanoparticles (NPs) of Ni with different sizes endows its distinctive physical and chemical properties, which represents a typical strategy for the development of high-performance catalysts. However, the size effect of metallic Ni-NPs on electrocatalytic performance remains ambiguous. Herein, the Ni-NPs with different sizes supported on nitrogen doped carbon (NC) has been synthesized by controlling the pyrolysis temperature, leading to the synthesis of Ni@NC-500 (8.3 nm), Ni@NC-280 (1.9 nm) and Ni@NC-200 (1.0 nm). The electrooxidation of benzyl alcohol (BA) over these nanocatalysts shows the yield of benzoic acid was 99%, 82%, 55% on Ni@NC-280, Ni@NC-200 and Ni@NC-500, respectively. The experimental and theoretical simulation demonstrate that the difference in the adsorption strength of reactant molecules by Ni-NPs is responsible for their different performance, where the Ni@NC-280 exhibits an optimal adsorption configuration between Ni@NC-280 electrode and BA. This work provides a new angle for designing and synthesizing efficient electrocatalysts, which may be extended to the exploration of various promising electrocatalytic systems.