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Defect engineering is crucial in tailoring photocatalytic efficiency, but it suffers from uncertainty in determining the vacancy type and in which type of the vacancy can better promote the photocatalytic efficiency. In this study, Bi2S3 nanorods with bismuth or sulfur vacancies were synthesized to investigate their distinct effects on the electronic structure, electron–hole separation characteristics, and near‐infrared (NIR)‐driven photocatalytic bacterial inactivation activity. Both bismuth and sulfur vacancies can enhance the light absorption ability of Bi2S3. However, the lifetime of photoinduced electrons is extended by bismuth vacancies but shortened by sulfur vacancies. Owing to these tendencies, Bi2S3 with Bi vacancies fully inactivated 7 log E. coli cells within 40 min of NIR irradiation, displaying better NIR‐driven photocatalytic bacterial inactivation efficiency than Bi2S3 with S vacancies. This study discloses the defect‐type‐dependent photocatalytic behaviors, providing new insights into designing highly efficient photocatalysts. Special defects: Bi2S3 nanorods with Bi or S vacancies were synthesized to investigate their effects on the electronic structure, electron–hole separation, and near‐infrared‐driven photocatalytic bacterial inactivation activity. Both bismuth and sulfur vacancies can enhance the light absorption ability of Bi2S3. This study discloses the defect‐type‐dependent photocatalytic behaviors, providing new insights into designing highly efficient photocatalysts. [ABSTRACT FROM AUTHOR]

Light-driven generation of H2O2 only from water and molecular oxygen could be an ideal pathway for clean production of solar fuels. In this work, a mixed metal oxide/graphitic-C3N4 (MMO@C3N4) composite was synthesized as a dual-functional photocatalyst for both water oxidation and oxygen reduction to generate H2O2. The MMO was derived from a NiFe-layered double hydroxide (LDH) precursor for obtaining a high dispersion of metal oxides on the surface of the C3N4 matrix. The C3N4 is in the graphitic phase and the main crystalline phase in MMO is cubic NiO. The XPS analyses revealed the doping of Fe3+ in the dominant NiO phase and the existence of surface defects in the C3N4 matrix. The formation and decomposition kinetics of H2O2 on the MMO@C3N4 and the control samples, including bare MMO, C3N4 matrix, Ni- or Fe-loaded C3N4 and a simple mixture of MMO and C3N4, were investigated. The MMO@C3N4 composite produced 63 μmol L−1 of H2O2 in 90 min in acidic solution (pH 3) and exhibited a significantly higher rate of production for H2O2 relative to the control samples. The positive shift of the valence band in the composite and the enhanced water oxidation catalysis by incorporating the MMO improved the light-induced hole collection relative to the bare C3N4 and resulted in the enhanced H2O2 formation. The positively shifted conduction band in the composite also improved the selectivity of the two-electron reduction of molecular oxygen to H2O2. [ABSTRACT FROM AUTHOR]