Engineering a local acid-like environment in alkaline medium for efficient hydrogen evolution reaction
Hao Tan, Bing Tang, Ying Lü, Qianqian Ji, Liyang Lv, Hengli Duan, Na Li, Yao Wang, Sihua Feng, Zhi Li, Chao Wang, Fengchun Hu, Zhihu Sun, Wensheng Yan
Abstract
Abstract Tuning the local reaction environment is an important and challenging issue for determining electrochemical performances. Herein, we propose a strategy of intentionally engineering the local reaction environment to yield highly active catalysts. Taking Pt δ− nanoparticles supported on oxygen vacancy enriched MgO nanosheets as a prototypical example, we have successfully created a local acid-like environment in the alkaline medium and achieve excellent hydrogen evolution reaction performances. The local acid-like environment is evidenced by operando Raman, synchrotron radiation infrared and X-ray absorption spectroscopy that observes a key H 3 O + intermediate emergence on the surface of MgO and accumulation around Pt δ− sites during electrocatalysis. Further analysis confirms that the critical factors of the forming the local acid-like environment include: the oxygen vacancy enriched MgO facilitates H 2 O dissociation to generate H 3 O + species; the F centers of MgO transfers its unpaired electrons to Pt, leading to the formation of electron-enriched Pt δ− species; positively charged H 3 O + migrates to negatively charged Pt δ− and accumulates around Pt δ− nanoparticles due to the electrostatic attraction, thus creating a local acidic environment in the alkaline medium.