Preparation of nitrogen-doped ZnIn2S4 microflowers for enhanced visible-light photocatalytic H2O2 production

N-doped ZnIn 2 S 4 microflowers synthesized via one-step solvothermal method using DMF as N source. • N doping introduces sulfur vacancies and negatively shifts the conduction band of ZIS. • Optimized N30-ZIS achieves H 2 O 2 production of 350 μmol g −1  h −1 under visible light. • EPR spin-trapping confirms the exclusive two-electron ORR pathway with ·O 2 − as key intermediate. • Structure-defect-activity relationship established for N-doped sulfide photocatalysts. The photocatalytic production of hydrogen peroxide (H 2 O 2 ) via the oxygen reduction reaction (ORR) represents a sustainable alternative to the energy-intensive anthraquinone process. However, the efficiency of this approach is limited by the rapid recombination of photogenerated carriers and a lack of active surface sites. Herein, nitrogen-doped ZnIn 2 S 4 (N-ZIS) microflowers were synthesized via a one-step solvothermal method using N , N -dimethylformamide (DMF) as the nitrogen source. The optimized N30-ZIS sample (with 30 mL of DMF) achieves an H 2 O 2 production rate of 350 μmol g −1  h −1 under visible light irradiation (λ ≥ 420 nm), which is 1.5 times that of pristine ZIS. Nitrogen doping introduces sulfur vacancies and modulates the electronic band structure, leading to enhanced charge separation and a more negative conduction band potential. Mechanistic studies confirm that H 2 O 2 generation proceeds via a two-electron oxygen reduction pathway involving ·O 2 − as the key intermediate. This work demonstrates that controlled nitrogen doping is an effective strategy to boost the photocatalytic H 2 O 2 production performance of ZIS-based materials. Nitrogen-doped ZnIn 2 S 4 (N-ZIS) microflowers are synthesized via a one-step solvothermal route using DMF as the N source. The optimized N30-ZIS delivers a visible-light H 2 O 2 production rate of 350 μmol g −1  h −1 (1.5 times that of pristine ZIS). Nitrogen doping creates sulfur vacancies and downshifts the conduction band, boosting charge separation and enabling a two-electron O 2 reduction pathway with ·O 2 − as the key intermediate. This work establishes controlled N-doping as a facile strategy to enhance photocatalytic ORR for sustainable H 2 O 2 synthesis. Download: Download high-res image (113KB) Download: Download full-size image