Atomic-thick metastable phase RhMo nanosheets for hydrogen oxidation catalysis
Juntao Zhang, Xiaozhi Liu, Yujin Ji, Xuerui Liu, Dong Su, Zhongbin Zhuang, Yu‐Chung Chang, Chih‐Wen Pao, Qi Shao, Zhiwei Hu, Xiaoqing Huang
Abstract
Abstract Metastable phase two-dimensional catalysts provide great flexibility for modifying their chemical, physical, and electronic properties. However, the synthesis of ultrathin metastable phase two-dimensional metallic nanomaterials is highly challenging, mainly due to the anisotropic nature of metallic materials and their thermodynamically unstable ground-state. Here, we report free-standing RhMo nanosheets with atomic thickness and a unique core/shell (metastable phase/stable phase) structure. The polymorphic interface between the core region and shell region stabilizes and activates metastable phase catalysts; the RhMo Nanosheets/C shows excellent hydrogen oxidation activity and stability. Specifically, the mass activities of RhMo Nanosheets/C is 6.96 A mg Rh −1 ; this is 21.09 times higher than that of commercial Pt/C (0.33 A mg Pt −1 ). Density functional theory calculations suggest that the interface aids in the dissociation of H 2 and the H species can then spillover to weak H binding sites for desorption, providing excellent hydrogen oxidation activity for RhMo nanosheets. This work advances the highly controlled synthesis of two-dimensional metastable phase noble metals and provides great directions for the design of high-performance catalysts for fuel cells and beyond.