Synthesis and properties of nanoporous Ag2S/CuS catalyst for hydrogen evolution reaction
By Hongtao Ren and Wence Xu and Shengli Zhu and Zhenduo Cui and Xianjin Yang and Akihisa Inoue
Published in Electrochimica Acta
2016
Abstract
Nanoporous CuS and Ag2S/CuS composite are synthesized by chemical dealloying method. The Ag2S content of the composite catalysts is controlled by Ag atom in the original amorphous alloys. The composite catalysts reveal an good activity for hydrogen evolution reaction (HER) with a small potential of ?0.2 V when current density is 10 mA cm?2 and a high current density of 163.4 mA cm?2 at 400 mV overpotential, which is associated with the enriched active sites on CuS and the improved electrical conductivity by Ag2S. The Tafel slope of Ag2S/CuS (75 mV dec?1) indicates that the combination of \VH\ (Volmer-Heyrovsky) and \VT\ (Volmer-Tafel) mechanisms might be involved to produce molecular hydrogen over Ag2S/CuS catalysts and the rate-determining step is likely some other than purely Heyrovsky or Tafel step. In addition, the composites exhibit good durability in acidic electrolytes and this method would open up a new type of highly efficient electrocatalyst.