Selective photoelectrochemical synthesis of adipic acid using single-atom Ir decorated α-Fe<sub>2</sub>O<sub>3</sub> photoanode.

Si, Shenghe; Mao, Yuyin; Liu, Ying-Ao; Ma, Jun; Jiang, Weiyi; Zhao, En-Dian; Song, Kepeng; Cheng, Hefeng et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Photoelectrochemical (PEC) synthesis offers a sustainable route for fine chemicals production, yet comprehending and modulating the reaction processes at the atomic level remains a challenge. Herein, we develop a single-atom Ir decorated Ti-doped α-Fe<sub>2</sub>O<sub>3</sub> photoanode for selective PEC synthesis of adipic acid from cyclohexanone using water as the oxygen source. The PEC system achieves 6.0 μmol cm<sup>-2</sup> h<sup>-1</sup> adipic acid production with ~60% Faradaic efficiency and ~88% selectivity. The single-atom Ir promotes the photogenerated carrier separation and transfer, while regulating the electronic structure of Ti-doped α-Fe<sub>2</sub>O<sub>3</sub> photoanode to optimize its adsorption strength of OH<sup>-</sup> and cyclohexanone. Mechanistic studies reveal a non-free-radical reaction pathway at the atomic level, driven by photogenerated holes through an adsorbed hydroxyl transfer. Notably, integrating the photoanode and an amorphous silicon-based photocathode leads to a bias-free PEC device that enables stable adipic acid production for over 80 hours, underscoring the potential for sustainable light-driven synthesis.