Developing Ni single-atom sites in carbon nitride for efficient photocatalytic H<sub>2</sub>O<sub>2</sub> production.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37932292.
- Also identified by DOI 10.1038/s41467-023-42887-y and PMC identifier 10628073.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Photocatalytic two-electron oxygen reduction to produce high-value hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is gaining popularity as a promising avenue of research. However, structural evolution mechanisms of catalytically active sites in the entire photosynthetic H<sub>2</sub>O<sub>2</sub> system remains unclear and seriously hinders the development of highly-active and stable H<sub>2</sub>O<sub>2</sub> photocatalysts. Herein, we report a high-loading Ni single-atom photocatalyst for efficient H<sub>2</sub>O<sub>2</sub> 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<sub>3</sub> sites dynamically transform into high-valent O<sub>1</sub>-Ni-N<sub>2</sub> sites after O<sub>2</sub> adsorption and further evolve to form a key *OOH intermediate before finally forming HOO-Ni-N<sub>2</sub>. 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<sub>2</sub>O<sub>2</sub> production activity and selectivity.