Amorphous FeOOH-modified ZIF-67-derived NiCo-LDH heterojunction for enhanced photocatalytic O2 activation and H2O2 production

This study developed an S-scheme heterojunction by anchoring amorphous FeOOH onto ZIF-67-derived NiCo-LDH porous nanocages for efficient photocatalytic H 2 O 2 production. The amorphous FeOOH provides abundant oxygen vacancies and unsaturated Fe sites that enhance O 2 adsorption and activation, while the intimate interface establishes a built-in electric field that drives S-scheme charge transfer. Under visible-light irradiation in air-saturated pure water, the optimized 30-FNC achieved a H 2 O 2 yield of 374.4 μmol·g −1 within 120 min, 6.08 and 3.28 times those of pure NiCo-LDH and FeOOH. UPS, Mott-Schottky, and in-situ XPS measurements jointly verified the S-scheme pathway, in which strongly reducing electrons are preserved on NiCo-LDH and strongly oxidizing holes on FeOOH, while TRPL further showed a prolonged average carrier lifetime. Radical scavenging and in-situ DRIFTS analysis identified a two-step single-electron pathway (O 2 → ·O 2 ⁻ → ·OOH → H 2 O 2 ), during which hole-driven water oxidation on FeOOH supplies protons. 30-FNC also exhibited excellent cycling stability over five runs. This research introduces a novel approach for the design of efficient LDH-based photocatalysts and underscores the significant role of oxygen activation in the sustainable production of H 2 O 2 .