Ni掺杂MoS2/石墨烯催化剂的制备及其电催化析氢活性

为了制备高效、低成本的析氢反应电催化剂，采用一步水热法制备镍掺杂二硫化钼/石墨烯复合材料(Ni_x-MoS₂/G，x=0.03，0.05，0.10)，并用X-射线衍射（XRD）、扫描电镜（SEM）、高分辨透射电镜（HRTEM）和X-射线光电子能谱（XPS）对其进行表征，讨论镍掺杂对复合材料的微观结构和电催化析氢性能的影响. 结果表明，与MoS₂/G催化剂相比，镍掺杂的MoS₂/G催化剂显示了更高的电催化析氢性能，尤其当水热反应体系中的Ni和Mo的摩尔比为1∶20时，制备的Ni_0.05-MoS₂/G显示了最强的电催化析氢性能，其塔菲尔斜率为50.8 mV/dec. 电催化活性的增强主要是由于少量镍的掺杂改变了复合催化剂的形貌，使MoS₂纳米片更好地负载在石墨烯表面，暴露出更多的催化活性位点，同时镍掺杂提高了MoS₂边缘活性位的固有催化活性.

Synthesis of Ni-doped MoS2/graphene hybrids and their electrocatalytic activity for hydrogen evolution reaction

In order to develop cost-effective electrocatalysts for hydrogen evolution reaction (HER), Ni-doped MoS₂/graphene (Ni_x-MoS₂/G, x=0.03, 0.05, 0.10) hybrids were fabricated by one-pot hydrothermal method. The hybrids were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS). The effects of Ni-doping on the microstructure and the electrocatalytic HER activity of the hybrids were investigated. Results showed that the Ni-doped MoS₂/G catalysts exhibited better electrocatalytic HER activity than MoS₂/G catalyst. Among these hybrids, the Ni_0.05-MoS₂/G hybrid (the mole ratio of Ni∶Mo for 1∶20 in the hydrothermal reaction system) exhibited the highest electrocatalytic HER activity with a Tafel slope of 50.8 mV/dec. The improvement of electrocatalytic activity can be contributed to that the rotational Ni-doping changes the morphology of the hybrid in which MoS₂ nanosheets can be well dispersed on the surface of graphene and more active sites for HER are displayed. In addition, Ni-doping enhances the intrinsic catalytic activity of MoS₂ edge sites for HER.