Constructing heterojunctions between two semiconductors with matched band structure is an effective strategy to acquire high‐efficiency photocatalysts. The S‐scheme heterojunction system has shown great potential in facilitating separation and transfer of photogenerated carriers, as well as acquiring strong photoredox ability. Herein, a 0D/2D S‐Scheme heterojunction material involving CeO2 quantum dots and polymeric carbon nitride (CeO2/PCN) is designed and constructed by in situ wet chemistry with subsequent heat treatment. This S‐scheme heterojunction material shows high‐efficiency photocatalytic sterilization rate (88.1 %) towards Staphylococcus aureus (S. aureus) under visible‐light irradiation (λ≥420 nm), which is 2.7 and 8.2 times that of pure CeO2 (32.2 %) and PCN (10.7 %), respectively. Strong evidence of S‐scheme charge transfer path is verified by theoretical calculations, in situ irradiated X‐ray photoelectron spectroscopy, and electron paramagnetic resonance.

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This work demonstrates the development of hierarchical ultra-thin g-C3N4 nanosheets with enhanced photocatalytic CO2 reduction activity.

Constructing two-dimensional (2D) composites using layered materials is considered to be an effective approach to achieve high-efficiency photocatalysts. Herein, a 2D/2D g-C 3 N 4 /MnO 2 heterostructured photocatalyst was synthesized via in situ growth of MnO 2 nanosheets on the surface of g-C 3 N 4 nanolayers using a wet-chemical method. The hybrid nanomaterial was characterized by a range of techniques to study its micromorphology, structure, chemical composition/states, and so on. The g-C 3 N 4 /MnO 2 nanocomposite exhibited greatly improved photocatalytic activities for dye degradation and phenol removal in comparison to the single g-C 3 N 4 or MnO 2 component. On the basis of the electron paramagnetic resonance spectra, X-ray photoelectron spectra, and the Mott− Schottky measurements, we consider that a Z-scheme heterojunction was generated between the g-C 3 N 4 nanosheets and MnO 2 nanosheets, wherein the photoinduced electrons in MnO 2 combined with the holes in g-C 3 N 4 , leading to enhanced charge carrier extraction and utilization upon photoexcitation. This work provides an effective approach to construct the 2D/2D heterojunctions for the application in solar-to-fuel conversion and photocatalytic water treatment.

Polymeric carbon nitrides are promising photocatalysts for CO2 photoreduction, but still show lower activity and selectivity. Herein, the synthesis of an ordered crystalline carbon nitride is reported which is simultaneously rich in special defects, accomplished via the co‐condensation of guanidine hydrochloride and dicyandiamide under acetonitrile‐promoted solvothermal conditions. The high crystallinity boosts charge migration, and the structural terminations with cyano and carboxyl groups result in the improvement of optical absorption, the ability to store charges at the surface, and CO2 binding. The crystalline carbon nitride with surface defect design enables the effective gas‐phase CO2 photoreduction into hydrocarbon fuels while oxidizing water to oxygen, at a rate of 12.07 µmol h−1 g−1 and a selectivity of 91.5%, both values of which are remarkably higher than those of most previous carbon nitride photocatalysts. This study highlights the preparation of defective crystalline carbon nitride using a low‐temperature solvothermal synthesis, as well as a resultant good selectivity toward hydrocarbons in the application of gas‐phase CO2 photoreduction in the absence of any cocatalyst or sacrificial agent.

Construction of heterojunctions has aroused great interest recently in the photocatalysis field because of the special electronic band structure and unique physicochemical properties. In this work, a novel 0D/3D CuO/ZnO heterojunction was obtained via in situ deposition of CuO nanoparticles on the flowerlike ZnO surface using the wet chemistry method. After depositing CuO nanoparticles onto the ZnO, the CuO/ZnO heterojunction exhibits enhanced visible-light harvesting and effective separation of the photogenerated electron–hole pairs compared with those in the pure ZnO. The photocatalytic removal efficiency of phenol over the CuO/ZnO heterojunction is up to 78% under the irradiation of the light, which is ∼2 and ∼4 times higher than those of the pristine ZnO and CuO, respectively. This composite also presents good durability and stability for phenol degradation in the photocatalytic reactions. Additionally, in the photodegradation system of the CuO/ZnO heterojunction, the superoxide radicals (•O2 –) and hydroxyl radicals (•OH) are confirmed as the active species by the trapping experiments. This research provides a promising way to achieve 0D/3D heterojunctions for the application in environmental purification and remedy.

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Development of a high-efficiency heterojunction with an improved photocatalytic property is regarded as a promising way to decontaminate wastewater. Herein, the direct novel Z-scheme heterojunction formed between CeO 2 nanoparticles and hierarchical ZnO was synthesized through the wet chemistry method and then the heat-treatment technique. The as-synthesized ZnO/CeO 2 composites display highly enhanced photocatalytic rhodamine B (RhB) degradation compared with pristine ZnO and CeO 2 . Specifically, ZnO/CeO 2 -3 (mass fraction of CeO 2 , 30%) shows good photostability and the best removal efficiency for photodegradated RhB, which are almost 2.5 and 1.7 times than pristine ZnO and CeO 2 , respectively. On the basis of the detailed characterizations and the degradation behavior of as-prepared samples over RhB, the formed heterojunction between the hierarchical ZnO and CeO 2 nanoparticles is confirmed as the direct Z-scheme heterojunction. The heterojunction system shows fast transfer, high-efficiency separation, and long lifetime of photoinduced charge carriers, as well as enhanced redox capacity. This study affords a novel approach to construct ZnO-based Z-scheme heterojunctions for the photocatalytic applications.