Kwon Ik Seon, Kwak In Hye, Ju Suyeon, Kang Sungwoo, Han Seungwu, Park Yun Chang, Park Jucheol, Park Jeunghee
Department of Advanced Materials Chemistry, Korea University, Sejong 339-700, Republic of Korea.
Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Korea.
ACS Nano. 2020 Sep 22;14(9):12184-12194. doi: 10.1021/acsnano.0c05874. Epub 2020 Sep 2.
Two-dimensional Re dichalcogenide nanostructures are promising electrocatalysts for the hydrogen evolution reaction (HER). Herein, we report the adatom doping of various transition metals (TM = Mn, Fe, Co, Ni, and Cu) in ReSe nanosheets synthesized using a solvothermal reaction. As the atomic number of TM increases from Mn to Cu, the adatoms on Re sites become more favored over the substitution. In the case of Ni, the fraction of adatoms reaches 90%. Ni doping resulted in the most effective enhancement in the HER catalytic performance, which was characterized by overpotentials of 82 and 109 mV at 10 mA cm in 0.5 M HSO and 1 M KOH, respectively, and the Tafel slopes of 54 and 81 mV dec. First-principles calculations predicted that the adatom doping structures (TMs on Re sites) have higher catalytic activity compared with the substitution ones. The adsorbed H atoms formed a midgap hybridized state via direct bonding with the orbitals of TM adatom. The present work provides a deeper understanding into how TM doping can provide the catalytically active sites in these ReSe nanosheets.
二维二碲化铼纳米结构是用于析氢反应（HER）的有前景的电催化剂。在此，我们报道了在通过溶剂热反应合成的ReSe纳米片中各种过渡金属（TM = Mn、Fe、Co、Ni和Cu）的吸附原子掺杂。随着TM的原子序数从Mn增加到Cu，Re位点上的吸附原子比取代更受青睐。在Ni的情况下，吸附原子的比例达到90%。Ni掺杂导致HER催化性能最有效的增强，其特征在于在0.5 M HSO和1 M KOH中，在10 mA cm时过电位分别为82和109 mV，塔菲尔斜率分别为54和81 mV dec。第一性原理计算预测，与取代结构相比，吸附原子掺杂结构（Re位点上的TMs）具有更高的催化活性。吸附的H原子通过与TM吸附原子的轨道直接键合形成了中间能隙杂化态。本工作为TM掺杂如何在这些ReSe纳米片中提供催化活性位点提供了更深入的理解。
