Deng Shengjue, Yang Fan, Zhang Qinghua, Zhong Yu, Zeng Yinxiang, Lin Shiwei, Wang Xiuli, Lu Xihong, Wang Cai-Zhuang, Gu Lin, Xia Xinhui, Tu Jiangping
State Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province, and Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China.
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, P. R. China.
Adv Mater. 2018 Jul 5:e1802223. doi: 10.1002/adma.201802223.
Tailoring molybdenum selenide electrocatalysts with tunable phase and morphology is of great importance for advancement of hydrogen evolution reaction (HER). In this work, phase- and morphology-modulated N-doped MoSe /TiC-C shell/core arrays through a facile hydrothermal and postannealing treatment strategy are reported. Highly conductive TiC-C nanorod arrays serve as the backbone for MoSe nanosheets to form high-quality MoSe /TiC-C shell/core arrays. Impressively, continuous phase modulation of MoSe is realized on the MoSe /TiC-C arrays. Except for the pure 1T-MoSe and 2H-MoSe , mixed (1T-2H)-MoSe nanosheets are achieved in the N-MoSe by N doping and demonstrated by spherical aberration electron microscope. Plausible mechanism of phase transformation and different doping sites of N atom are proposed via theoretical calculation. The much smaller energy barrier, longer HSe bond length, and diminished bandgap endow N-MoSe /TiC-C arrays with substantially superior HER performance compared to 1T and 2H phase counterparts. Impressively, the designed N-MoSe /TiC-C arrays exhibit a low overpotential of 137 mV at a large current density of 100 mA cm , and a small Tafel slope of 32 mV dec . Our results pave the way to unravel the enhancement mechanism of HER on 2D transition metal dichalcogenides by N doping.
定制具有可调相和形态的硒化钼电催化剂对于析氢反应（HER）的进展至关重要。在这项工作中，报道了通过简便的水热和退火后处理策略制备的相和形态调制的N掺杂MoSe₂/TiC-C核壳阵列。高导电性的TiC-C纳米棒阵列作为MoSe₂纳米片的骨架，形成高质量的MoSe₂/TiC-C核壳阵列。令人印象深刻的是，在MoSe₂/TiC-C阵列上实现了MoSe₂的连续相调制。除了纯的1T-MoSe₂和2H-MoSe₂，通过N掺杂在N-MoSe₂中获得了混合的(1T-2H)-MoSe₂纳米片，并通过球差电子显微镜进行了表征。通过理论计算提出了合理的相变机制和N原子的不同掺杂位点。与1T和2H相的对应物相比，更小的能垒、更长的H-Se键长度和减小的带隙使N-MoSe₂/TiC-C阵列具有显著优越的HER性能。令人印象深刻的是，所设计的N-MoSe₂/TiC-C阵列在100 mA cm⁻²的大电流密度下表现出137 mV的低过电位和32 mV dec⁻¹的小塔菲尔斜率。我们的结果为揭示N掺杂对二维过渡金属二硫属化物HER增强机制铺平了道路。
