Component-controllable synthesis of Co(S_xSe_1-x)₂ nanowires supported by carbon fiber paper as high-performance electrode for hydrogen evolution reaction

The ternary alloyed Co(S_xSe_1-x)₂ nanowires (NWs) supported by carbon fiber paper (CFP) have been successfully synthesized. By adjusting the components of the NWs, it is found that the Co(S_0.73Se_0.27)₂ NWs on CFP exhibit the highest electrocatalytic activity towards hydrogen evolution reaction (HER). To drive the current density of 100mVcm^-2, the Co(S_0.73Se_0.27)₂ NWs only require a small overpotential of 157mV in 0.5M H₂SO₄ solution and the corresponding Tafel slope is only 45.3mVdec^-1. After 20h continuous electrolysis or cycling for 5000 times in acid electrolyte, the robust catalytic activity is still perfectly preserved. DFT calculation results demonstrate that the high intrinsic activity of Co(S_0.73Se_0.27)₂ NWs towards HER is derived from the significant reduction of kinetic energy barrier induced by anion doping. This work presents a new efficient catalyst for HER and the anion doping strategy implemented here could be extended to other earth-abundant electrocatalysts to improve the catalytic performance.