Controlled Synthesis Of Molybdenum Carbide-Based Composites For HER

Precious metal catalysts possess perfect catalytic activity and good stability for hydrogen evolution reaction（HER）.While the high cost and limit reservation limited their applications.Recently,non-noble metal materials have attracted much attention for their low cost and better electrochemical performance.Mo-based composites has the advantage of high electrical conductivity,prefect catalytic properties and structural stability when used as HER catalysts.Therefore,molybdenum carbide composites obtained through different methods were developed in this paper.The catalytic activity of these materials for HER,and the intrinsic kinetic which contribute to high catalytic preference are studied.The results are as follows:（1）Mo₂C composites were obtained via a two-step synthetic route of hydrothermal and post-annealing.The temperature of hydrothermal and post-annealing was investigated detailedly to obtain six Mo₂C composites(Mo₂C/CNT_S200-700,Mo₂C/CNT_S200-800,Mo₂C/CNT_S200-900,Mo₂C/CNT_S180-800,Mo₂C/CNT_S220-800 and Mo₂C/CNT_S240-800).The better performance of as-prepared six catalysts may attribute to high electro-conductivity and the ultra-small particle size.In addition,Mo₂C/CNT_S200-800 showed best performance in 0.5M H₂SO₄ or 1 M KOH solution,which was due to the large electrochemical activity area,good electrical conductivity and small resistance.（2）Controllable synthesis of MoO₂/C,MoC/C,and Mo₂C/C catalysts were conductd by tuning the proportion of glucose and ammonium molybdate.Compared with the other two catalysts,Mo₂C/C showed the best catalytic activity in both 0.5 M H₂SO₄ and 1 M KOH solution,the enhanced catalytic activity was originated from large specific surface area,high electro-conductivity and the ultra-small particle size.（3）Mo₂C/NCS-5,Mo₂C/NCS-10,MoC/NCS-15 and MoC/NCS-20 catalysts were prepared by tuning the proportion of melamine and ammonium molybdate.As a result,the obtained Mo₂C/NCS-10 showed excellent catalytic activity when compared with other three materials,the enhanced catalytic activity is caused by its’high electro-conductivity,large specific surface area and more active sites.