The widespread use of antibiotics has caused the rapid emergence of antibiotic‐resistant bacterial strains and antibiotic resistance genes in the past few decades. Photocatalytic inactivation, a promising approach for the killing of pathogens, efficiently avoids the problems induced by antimicrobial drugs. However, traditional photocatalysts usually have some disadvantages, such as high costs of raw materials, ultraviolet ray excitation, and potential leaching of toxic metals. Here, a metal‐free heterojunction photocatalyst, denoted as CQDs/g‐C3N4, is synthesized through incorporating carbon quantum dots (CQDs) on graphitic carbon nitride (g‐C3N4), which significantly enhances photocatalytic inactivation of Staphylococcus aureus (S. aureus) compared with pure g‐C3N4 in vitro. CQDs/g‐C3N4 causes a rapid increase of intracellular reactive oxygen species levels and destruction of cell membranes under visible light, eventually leading to death of bacteria. The efficacy of CQDs/g‐C3N4 is further examined by a mouse cutaneous infection model of S. aureus. CQDs/g‐C3N4 markedly reduces the bacterial loads and prompts lesion recovery in mice, as compared with g‐C3N4‐treated group. In vivo and in vitro toxicity analyses show that the side effects of CQDs/g‐C3N4 are negligible. Considering the efficient photocatalytic inactivation and nontoxicity of CQDs/g‐C3N4, this visible‐light‐driven photocatalyst paves a brand new avenue for the treatment of S. aureus infection.

Photocatalytic conversion of CO2 can provide a solution for simultaneously addressing global warming and solar fuel generation. However, its applicability is presently limited by the unsatisfactory photoconversion efficiency of the state‐of‐art photocatalysts. In this regard, enhancing CO2 adsorption through surface modification could be an efficient way to improve the photoconversion efficiency. Herein, doping of nonpolar carbon quantum dots (CQDs) onto g‐C3N4 is reported for the construction of a metal‐free heterojunction photocatalyst (CQDs/g‐C3N4). CQDs offer several advantages such as band‐gap reduction and electron‐withdrawing effect to improve light absorption and photocarrier separation efficiency. However, this study reveals that nonpolar CQDs could also improve CO2 adsorption, photoinduced H2 production, reaction kinetics, and alter CO2 photoreduction pathways to generate CH4. Consequently, the CQDs/g‐C3N4 could generate six times more CO and CH4 without detectable H2 compared to pristine g‐C3N4, under similar conditions. Therefore, this study demonstrates a promising strategy for efficient adsorption, activation, and subsequent photoreduction of CO2 by nonpolar surface modification of g‐C3N4.

BaTaO 2 N with intense visible light absorption has been demonstrated as a promising photocatalyst for Z-scheme overall water splitting, whereas the photocatalytic activity of BaTaO 2 N is still restricted by strong charge recombination at structural defects. Here, we present the direct growth of BaTaO 2 N–BaNa 0.25 Ta 0.75 O 3 solid solution from a lattice-matched BaNa 0.25 Ta 0.75 O 3 precursor through volatilization of Na species during a nitridation process. This method promotes the direct phase transformation from BaNa 0.25 Ta 0.75 O 3 to BaTaO 2 N to inhibit the formation of defect states. As a result, the as-obtained BaTaO 2 N–BaNa 0.25 Ta 0.75 O 3 solid solution shows greatly enhanced activity compared to the conventional BaTaO 2 N, regardless of photocatalytic H 2 evolution in the presence of methanol or Z-scheme overall water splitting. This study provides a facile method to construct (oxy)nitride-based solid solution photocatalysts with low defect density for efficient solar hydrogen production from water splitting.