材料科学
催化作用
相(物质)
堆积
插层(化学)
透射电子显微镜
电催化剂
吉布斯自由能
金属
过渡金属
结晶学
纳米技术
化学工程
电化学
物理化学
无机化学
电极
化学
有机化学
工程类
物理
量子力学
冶金
作者
Ik Seon Kwon,In Hye Kwak,Ju Yeon Kim,Seung‐Jae Lee,Qadeer Akbar Sial,Junaid Ihsan,Kug‐Seung Lee,Seung Jo Yoo,Jeunghee Park,Hong Seok Kang
标识
DOI:10.1002/adma.202307867
摘要
The phase control of transition metal dichalcogenides (TMDs) is an intriguing approach for tuning the electronic structure toward extensive applications. In this study, WSe2 nanosheets synthesized via a colloidal reaction exhibit a phase conversion from semiconducting 2H to metallic 2M under Se-rich growth conditions (i.e., increasing the concentration of Se precursor or lowering the growth temperature). High-resolution scanning transmission electron microscopy images are used to identify the stacking sequence of the 2M phase, which is distinctive from that of the 1T' phase. First-principles calculations employing various Se-rich models (intercalation and substitution) indicated that Se enrichment induces conversion to the 2M phase. The 2M phase WSe2 nanosheets with the Se excess exhibited enhanced electrocatalytic performance in the hydrogen evolution reaction (HER). In situ X-ray absorption fine structure studies suggested that the excess Se atoms in the 2M phase WSe2 enhanced the HER catalytic activity, which is supported by the Gibbs free energy (ΔGH* ) of H adsorption and the Fermi abundance function. These results provide an appealing strategy for phase control of TMD catalysts.
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