Preparation of Au/MoS2‐CNT@CNF Composite Electrocatalyst for High‐Efficiency Hydrogen Evolution Reaction

Abstract By virtue of excellent ion storage and fast ion‐diffusion rates, molybdenum disulfide (MoS 2 ) has been regarded as a promising electrocatalyst for hydrogen evolution reaction (HER). however, it is inherently inert to HER, its electrochemical activity is usually improved by enhancing electrical conductivity or increasing exposed active sites. To improve the conductivity and adsorption of MoS 2 , we prepared the MoS 4 ‐Ppy intermediate by oxidative polymerization. Taking advantage of the adsorption properties of MoS 4 ‐Ppy to combine with Au(III), Au(III) was simultaneously reduced to Au nanoparticles(Au NPs). Combining the Au/MoS 4 ‐Ppy with BC and converting it into a catalyst Au/MoS 2 ‐CNT@CNF by calcination, the catalyst activity was improved by optimizing the concentration of Au(III). Combining MoS 2 with Polypyrrole (Ppy) and Bacterial cellulose (BC) not only improves the conductivity of MoS 2 , but also increases the exposed active sites. Notably, the obtained 50 ppm Au/MoS 2 ‐CNT@CNFs exhibited good HER catalytic performance in an acidic electrolyte (0.5 M H 2 SO 4 ) with a low overpotential of only 108 mV at a current density of 10 mA ⋅ cm −2 , a low Tafel slope of 52.1 mV ⋅ dec −1 , and along with outstanding stability. The improvement of electrocatalytic activity is mainly attributed to the larger electrochemical specific surface area of the composites after adsorption of Au(III) and loaded BC. The low load Au NPs can provide dense active sites. Moreover, and synergistic effect among Au NPs, MoS 2 , and Ppy can greatly enhance the charge transfer efficiency and lead to excellent electron transfer ability, thus significantly improving the HER performance.