Phosphorus Optimized Metastable Hexagonal‐Close‐Packed Phase Nickel for Efficient Hydrogen Peroxide Production in Neutral Media

• Published in: Advanced functional materials Vol. 33; no. 25
• Main Authors: Geng, Shize, Ji, Yujin, Yang, Shize, Su, Jiaqi, Hu, Zhiwei, Chan, Ting‐Shan, Yu, Hao, Li, Youyong, Chin, Yi‐Ying, Huang, Xiaoqing, Shao, Qi
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.06.2023
• Subjects: 2e − ORR; Catalysts; Doping; dopings; Hydrogen peroxide; Materials science; Metastable phases; neutral medias; Nickel; Phosphorus; Solid electrolytes; Stability tests
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202300636

Direct synthesis of hydrogen peroxide (H2O2) through electrochemical oxygen reduction has gained close attention yet remains a great challenge due to the slow kinetics. Herein, combining with the virtues of the native high energy state and fascinating surface environment of metastable materials and doping strategy, an efficient phosphorus‐optimized metastable hexagonal‐close‐packed phase nickel catalyst (P‐hcp Ni), belonging to the space group (P63/mmc, 194), with P doping is demonstrated. Significantly, it achieves high selectivity of 97% and a high intrinsic turnover frequency of 2.34 s−1, much better than those of the stable face‐centered‐cubic Ni catalyst. It also displays high stability with remaining in the metastable phase after the stability test. More importantly, P‐hcp Ni also achieves a productivity of 4917.2 mmol gNi−1 h−1 and an accumulated concentration of (H2O2) of 2.38 mol L−1 after 130 h stability test in pure water with a solid electrolyte. Further investigation reveals that the P doping not only greatly enhances the stability of metastable phase, but also weakens the *OOH adsorption on the active site, promoting the high production of H2O2 in the neutral media. An efficient phosphorus‐optimized metastable hexagonal‐close‐packed phase nickel catalyst is first synthesized for 2e− oxygen reduction reaction under neutral conditions, where P doping can not only effectively stabilize the metastable hcp phase, but also attract electrons from the surrounding Ni to weaken the *OOH adsorption.