National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China , Hefei, Anhui 230029, China.
School of National Defense Science and Technology, Southwest University of Science and Technology , Mianyang, Sichuan 621010, China.
ACS Nano. 2017 Nov 28;11(11):11574-11583. doi: 10.1021/acsnano.7b06501. Epub 2017 Nov 15.
Developing highly active and low-cost heterogeneous catalysts toward overall electrochemical water splitting is extremely desirable but still a challenge. Herein, we report pyrite NiS nanosheets doped with vanadium heteroatoms as bifunctional electrode materials for both hydrogen- and oxygen-evolution reaction (HER and OER). Notably, the electronic structure reconfiguration of pyrite NiS is observed from typical semiconductive characteristics to metallic characteristics by engineering vanadium (V) displacement defect, which is confirmed by both experimental temperature-dependent resistivity and theoretical density functional theory calculations. Furthermore, elaborate X-ray absorption spectroscopy measurements reveal that electronic structure reconfiguration of NiS is rooted in electron transfer from doped V to Ni sites, consequently enabling Ni sites to gain more electrons. The metallic V-doped NiS nanosheets exhibit extraordinary electrocatalytic performance with overpotentials of about 290 mV for OER and about 110 mV for HER at 10 mA cm with long-term stability in 1 M KOH solutions, representing one of the best non-noble-metal bifunctional electrocatalysts to date. This work provides insights into electronic structure engineering from well-designed atomic defect metal sulfide.
开发高效且低成本的非均相催化剂以实现整体电化学水分解是非常理想的，但仍然具有挑战性。在此，我们报道了一种通过工程化钒（V）置换缺陷，将黄铁矿 NiS 纳米片掺杂钒杂原子作为用于析氢反应（HER）和析氧反应（OER）的双功能电极材料。值得注意的是，电子结构重组从典型的半导体特性到通过工程化钒（V）置换缺陷的金属特性，这通过实验温度依赖性电阻率和理论密度泛函理论计算得到证实。此外，精心的 X 射线吸收光谱测量表明，NiS 的电子结构重组源于掺杂 V 向 Ni 位的电子转移，从而使 Ni 位获得更多的电子。金属 V 掺杂的 NiS 纳米片在 1 M KOH 溶液中具有卓越的电催化性能，OER 的过电位约为 290 mV，HER 的过电位约为 110 mV，在 10 mA cm 下具有长期稳定性，是迄今为止最好的非贵金属双功能电催化剂之一。这项工作为通过精心设计的原子缺陷金属硫化物进行电子结构工程提供了新的思路。
