Electrocatalytic performance of ultrasmall Mo2C affected by different transition metal dopants in hydrogen evolution reaction
Electrocatalytic performance of ultrasmall Mo2C affected by different transition metal dopants in hydrogen evolution reaction
复制标题
不同过渡金属掺杂剂对超小型Mo2C析氢反应电催化性能的影响
DOI：
10.1039/c8nr00908b
复制
发表时间：
2018
期刊：
影响因子：
6.7
通讯作者：
Yangguang Li
中科院分区：
文献类型：
--
作者：
Feiyang Yu;Ya Gao;Zhongling Lang;Yuanyuan Ma;Liying Yin;Jing Du;Huaqiao Tan;Yonghui Wang;Yangguang Li
碳化钼因其与 Pt 相似的 d 带电子结构而被认为是一种用于析氢反应 (HER) 的优质无贵金属电催化剂。特别是，可以通过元素掺杂进一步调整此类材料的电子结构，以提高其电催化活性。在此，我们选择Anderson型多金属氧酸盐（POMs）（NH4）n[TMMo6O24H6]·5H2O（TM = Ni2+，Co2+，n = 4；TM = Fe3+，Cr3+，n = 3）作为前驱体，制备了新型过渡金属掺杂Mo2C材料。当这些POM与双氰胺（DCA）通过固体研磨混合并在高温下碳化时，得到了一系列由几层石墨碳壳覆盖的Ni、Co、Fe和Cr掺杂的Mo2C复合纳米粒子（简称TM-Mo2C@C）。所有这些纳米颗粒都具有相似的尺寸、形貌和TM/Mo组分比，因此可以系统地研究不同TM掺杂剂对Mo2C HER电催化活性的影响。电催化实验和DFT计算均表明TM掺杂剂对氢结合能（ΔGH*）和Mo2C的催化活性有显着影响。 HER电催化活性顺序为：Ni-Mo2C > Co-Mo2C > Fe-Mo2C > Cr-Mo2C。因此，Ni-Mo2C@C 具有最好的 HER 性能，在 10 mA cm−2 的电流密度下需要 72 mV 的过电势，塔菲尔斜率为 65.8 mV dec−1。这项工作为合理研究元素掺杂对碳化钼的影响并探索新型高效、低成本的HER电催化剂提供了一条捷径。
Molybdenum carbides are considered as one type of privileged noble-metal-free electrocatalysts for hydrogen evolution reactions (HER) due to their d-band electron structure, which is similar to Pt. Especially, the electronic structure of such materials can be further adjusted by elemental doping to improve their electrocatalytic activity. Herein, we selected the Anderson-type polyoxometalates (POMs) (NH4)n[TMMo6O24H6]·5H2O (TM = Ni2+, Co2+, n = 4; TM = Fe3+, Cr3+, n = 3) as precursors to prepare new transition-metal-doped Mo2C materials. When these POMs were mixed with dicyandiamide (DCA) by solid grinding, and carbonized at a high temperature, a series of Ni-, Co-, Fe-, and Cr-doped Mo2C composite nanoparticles covered by few-layer graphitic carbon shells (abbr. TM-Mo2C@C) were obtained. All these nanoparticles possess a similar size, morphology, and TM/Mo component ratio, and thus it is feasible to systematically investigate the influence of different TM dopants on the electrocatalytic activity of Mo2C for HER. Both electrocatalytic experiments and DFT calculations reveal that TM dopants have a significant effect on the hydrogen binding energy (ΔGH*) and the catalytic activity of Mo2C. The sequence of HER electrocatalytic activity is as follows: Ni-Mo2C > Co-Mo2C > Fe-Mo2C > Cr-Mo2C. As a result, Ni-Mo2C@C possesses the best HER performance, which required an overpotential of 72 mV at a current density of 10 mA cm−2 and the Tafel slope is 65.8 mV dec−1. This work suggests a shortcut to reasonably investigate the effects of elemental doping on molybdenum carbides and explore new high-efficient and low-cost electrocatalysts for HER.