Self-assembled Co_0.85Se/carbon nanowires as a highly effective and stable electrocatalyst for the hydrogen evolution...

Self-assembled Co_0.85Se/carbon nanowires, constructed by Co_0.85Se nanoparticles homogenously embedded into carbon nanowires (Co_0.85Se@CNWs), have been synthesized through a facile solvothermal reaction and selenylation process. Compared to the bare Co_0.85Se NWs, the Co_0.85Se@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_0.85Se@CNWs is attributed to its unique particle-in-nanowire architecture, which not only prevents the Co_0.85Se 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.