Ultrahigh Performance H<sub>2</sub>O<sub>2</sub> Generation by Single‐Atom Fe Catalysts with N/O Bidentate Ligand via Oxalic Acid and Oxygen Molecules Activation
Mingming Zhang, Cui Lai, Fuhang Xu, Danlian Huang, Tianjue Hu, Bisheng Li, Dengsheng Ma, Shiyu Liu, Yukui Fu, Ling Li, Lin Tang, Liang Chen
Abstract
Abstract Single‐atom catalysts (SACs) for photocatalytic hydrogen peroxide (H 2 O 2 ) generation are researched but it is still challenging to obtain high H 2 O 2 yields. Herein, graphite carbon nitride (Fe SA /CN) confined single Fe atoms with N/O coordination is prepared, and Fe SA /CN shows high H 2 O 2 production via oxalic acid and O 2 activation. Under visible light illumination, the concentration of H 2 O 2 generated by Fe SA /CN can achieve 40.19 mM g −1 h −1 , which is 10.44 times higher than that of g‐C 3 N 4 . The enhanced H 2 O 2 generation can be attributed to the formation of metal‐organic complexes and rapid electron transfer. Moreover, the O 2 activation of photocatalysts is revealed by 3,3′,5,5′‐tetramethylbenzidine oxidation. The results display that the O 2 activation capacity of Fe SA /CN is higher than that of g‐C 3 N 4 , which facilitates the formation of H 2 O 2 . Finally, density functional theory calculation demonstrates that O 2 is chemically adsorbed on Fe atomic sites. The adsorption energy of O 2 is enhanced from −0.555 to −1.497 eV, and the bond length of OO is extended from 1.235 to 1.292 Å. These results exhibit that the confinement of single Fe atoms can promote O 2 adsorption and activation. Finally, the photocatalytic mechanism is elaborated, which provides a deep understanding for SACs‐catalyzed H 2 O 2 generation.