Self-assembled Co 0.85 Se/carbon nanowires as a highly effective and stable electrocatalyst for the hydrogen evolution reaction.

Self-assembled Co 0.85 Se/carbon nanowires, constructed by Co 0.85 Se nanoparticles homogenously embedded into carbon nanowires (Co 0.85 Se@CNWs), have been synthesized through a facile solvothermal reaction and selenylation process. Compared to the bare Co 0.85 Se NWs, the Co 0.85 Se@CNW hybrid demonstrates high efficiency and stability for HER. It has a small Tafel slope of 43.4 mV dec -1 , a low onset potential of 138 mV vs. RHE, and a high cycling stability with more than 95% current retention after 1500 voltammetry cycles. The outstanding HER performance of Co 0.85 Se@CNWs is attributed to its unique particle-in-nanowire architecture, which not only prevents the Co 0.85 Se nanoparticles from aggregation, but also provides a highly conductive CNW matrix to promote the charge transfer in the electrocatalytic reaction, further enhancing the catalytic activity. This work provides a new strategy to rationally design transition metal-based selenide hybrids as highly effective and stable electrocatalysts for HER.