Developing Ni single-atom sites in carbon nitride for efficient photocatalytic H2O2 production

• Published in: Nature communications 2023-11, Vol.14 (1), p.7115-7115, Article 7115
• Main Authors: Zhang, Xu, Su, Hui, Cui, Peixin, Cao, Yongyong, Teng, Zhenyuan, Zhang, Qitao, Wang, Yang, Feng, Yibo, Feng, Ran, Hou, Jixiang, Zhou, Xiyuan, Ma, Peijie, Hu, Hanwen, Wang, Kaiwen, Wang, Cong, Gan, Liyong, Zhao, Yunxuan, Liu, Qinghua, Zhang, Tierui, Zheng, Kun
• Format: Article
• Language: English
• Subjects: 140/146; 147/143; 639/301/299/890; 639/638/77/890; 639/925/357/537; Absorption spectroscopy; Carbon; Carbon nitride; Evolution; Free energy; Heat of formation; Humanities and Social Sciences; Hydrogen peroxide; multidisciplinary; Photocatalysis; Photocatalysts; Raman spectroscopy; Science; Science (multidisciplinary); Spectrum analysis; Synchrotron radiation; Synchrotrons; X ray absorption; X-ray absorption spectroscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-42887-y

Photocatalytic two-electron oxygen reduction to produce high-value hydrogen peroxide (H 2 O 2 ) is gaining popularity as a promising avenue of research. However, structural evolution mechanisms of catalytically active sites in the entire photosynthetic H 2 O 2 system remains unclear and seriously hinders the development of highly-active and stable H 2 O 2 photocatalysts. Herein, we report a high-loading Ni single-atom photocatalyst for efficient H 2 O 2 synthesis in pure water, achieving an apparent quantum yield of 10.9% at 420 nm and a solar-to-chemical conversion efficiency of 0.82%. Importantly, using in situ synchrotron X-ray absorption spectroscopy and Raman spectroscopy we directly observe that initial Ni-N 3 sites dynamically transform into high-valent O 1 -Ni-N 2 sites after O 2 adsorption and further evolve to form a key *OOH intermediate before finally forming HOO-Ni-N 2 . Theoretical calculations and experiments further reveal that the evolution of the active sites structure reduces the formation energy barrier of *OOH and suppresses the O=O bond dissociation, leading to improved H 2 O 2 production activity and selectivity. Here, the authors explore how Ni single-atom sites on carbon nitride evolve under photocatalytic conditions. They show that this evolution plays a pivotal role in enhancing photocatalytic H 2 O 2 production.