The thermodynamically favorable electrocatalytic oxidation coupled with hydrogen evolution reaction (HER) is considered as a sustainable and promising technique. Nonetheless, it remains a great challenge due to the lack of simple, cheap, and high-efficient electrocatalysts. Here, we successfully develop a simple and scalable electro-deposition and subsequent phosphorization route to fabricate Ni-doped Co₂P (Ni-Co₂P) nanosheets catalyst using the in-situ released Ni species from defective Ni foam as metal source. Impressively, the as-synthesized Ni-Co₂P catalyst exhibits excellent electrochemical 5-hydroxymethylfurfural oxidation reaction (HOR) performance with > 99% 2,5-furandicarboxylic acid yield and > 97% Faradaic efficiency at an ultralow potential of 1.29 V vs. reversible hydrogen electrode (RHE). Experimental characterization and theoretical calculation reveal that the atomically doped Ni species can enhance the adsorption of reactant and thus lower the reaction energy barriers. By coupling the electrocatalytic HOR with HER, the employed two-electrode system using Ni-Co₂P and commercial Ni foam as anode and cathode, respectively, exhibits a low cell voltage of 1.53 V to drive a current density of 10 mA·cm⁻², which is 90 mV lower than that of pure water splitting. This work provides a facile and efficient approach for the preparation of high-performance earth-abundant electrocatalysts toward the concurrent production of H₂ and value-added chemicals.

Cu-based electrocatalysts have provoked much attention for their high activity and selectivity in carbon dioxide (CO₂) conversion into multi-carbon hydrocarbons. However, during the electrochemical reaction, Cu catalysts inevitably undergo surface reconstruction whose impact on CO₂ conversion performance remains contentious. Here we report that polycrystalline Cu nanoparticles (denoted as Cu-s) with rich high-index facets, derived from Cu_2−xS through desulphurization and surface reconstruction, offer an excellent platform for investigating the role of surface reconstruction in electrocatalytic CO₂ conversion. During the formation of Cu-s catalyst, the two stages of desulphurization and surface reconstruction can be clearly resolved by in situ X-ray absorption spectroscopy and OH⁻ adsorption characterizations, which are well correlated with the changes in electrocatalytic performance. It turns out that the high CO₂ conversion performance, achieved by the Cu-s catalyst (Faradic efficiency of 68.6% and partial current density of 40.8 mA/cm² in H-cell toward C₂H₄ production), is attributed to the increased percentage of high-index facets in Cu-s during the surface reconstruction. Furthermore, the operando electrochemical Raman spectroscopy further reveals that the conversion of the CO₂ into the C₂H₄ on Cu-s is intermediated by the production of *COCHO. Our findings manifest that the surface reconstruction is an effective method for tuning the reaction intermediate of the CO₂ conversion toward high-value multicarbon (C₂₊) chemicals, and highlight the significance of in situ characterizations in enhancing the understanding of the surface structure and its role in electrocatalysis.

Developing carbon-based electrocatalysts with excellent N₂ adsorption and activation capability holds the key to achieve highly efficient nitrogen reduction reaction (NRR) for reaching its practical application. Here, we report a highly active electrocatalyst— metal-free pyrrolic-N dominated N, S co-doped carbon (pyrr-NSC) for NRR. Based on theoretical and experimental results, it is confirmed that the N and S-dopants practice a working-in-tandem mechanism on pyrr-NSC, where the N-dopants are utilized to create electropositive C sites for enhancing N₂ adsorption and the S-dopants are employed to induce electron backdonation for facilitating N₂ activation. The synergistic effect of the pyrrolic-N and S-dopants can also suppress the irritating hydrogen evolution reaction, further boosting the NRR performance. This work gives an indication that the combination of two different dopants on electrocatalyst can enhance NRR performance by working in the two tandem steps—the adsorption and activation of N₂ molecules, providing a new strategy for NRR electrocatalyst design.