Robust direct Z-scheme exciton transfer dynamics by architecting 3D BiOI MF-supported non-stoichiometric Cu0.75In0.25S NC nanocomposite for co-catalyst-free photocatalytic hydrogen evolution

Recent advancement on quantum dot-coupled heterojunction structures in catalysis：A review

Photoelectrocatalysis stands as an exceptionally efficient and sustainable method, significantly addressing both energy scarcity and environmental pollution challenges. Within this realm, quantum dots (QDs) have garnered immense attention for their outstanding catalytic properties. Their unique features-cost-effectiveness, high efficiency, remarkable stability, and exceptional photovoltaic characteristics-set them apart from other tunable semiconductor materials. Heterojunction structures based on quantum dots remarkably boost solar energy conversion efficiency. This review aims to provide a comprehensive overview of the impacts generated by heterojunctions formed using diverse quantum dots and delve into their catalytic applications. Moreover, it sheds light on recent advancements utilizing quantum dots in modifying optoelectronic semiconductor materials for diverse purposes, ranging from hydrogen (H2) generation to carbon and nitrogen reduction, as well as pollutant degradation. Additionally, the paper offers valuable insights into challenges faced by quantum dot applications and outlines promising future prospects.

Remarkably enhanced catalytic performance in CoOx/Bi4Ti3O12 heterostructures for methyl orange degradation via piezocatalysis and piezo-photocatalysis

A novel heterojunction composite of CoOx/Bi4Ti3O12 was synthesized through a combination of molten salt and photodeposition methods. The optimal sample exhibited superior performance in the piezocatalytic degradation of methyl orange (MO) dye with a degradation rate of 1.09 h-1, which was 2.4 times higher than that of pristine Bi4Ti3O12. Various characterizations were conducted to reveal the fundamental nature accountable for the outstanding piezocatalytic performance of CoOx/Bi4Ti3O12. The investigation of the band structure indicated that the CoOx/Bi4Ti3O12 composite formed a type-I p-n heterojunction structure, with CoOx acting as a hole trapper to effectively separate and transfer piezogenerated carriers. Significantly, the MO degradation rate of the best CoOx/Bi4Ti3O12 sample further increased to 2.96 h-1 under combined ultrasonic vibration and simulated sunlight. The synergy between piezocatalysis and photocatalysis can be ascribed to the following factors. The photoexcitation process ensures the sufficient generation of charge carriers in the CoOx/Bi4Ti3O12, while the piezoelectric field within Bi4Ti3O12 promotes the separation of electron-hole pairs in the bulk phase. Furthermore, the heterojunction structure between Bi4Ti3O12 and CoOx significantly facilitates the surface separation of charge carriers. This increased involvement of free electrons and holes in the reaction leads to a remarkable enhancement in catalytic MO degradation. This work contributes to the understanding of the coupling mechanism between the piezoelectric effect and photocatalysis, and also provides a promising strategy for the development of efficient catalysts for wastewater treatment.

Preparation of NaNbO3 microcube with abundant oxygen vacancies and its high photocatalytic N2 fixation activity in the help of Pt nanoparticles

In this study, the photocatalytic N₂ immobilization performance of NaNbO₃ is enhanced via oxygen vacancy introduction and Pt loading. The designed Pt-loaded NaNbO₃ with rich oxygen defects (Pt/O-NaNbO₃) is synthesized by combining ion-exchange and photodeposition methods. Characterization result indicates that the O-NaNbO₃ has hollow microcube morphology and higher surface area than NaNbO₃. The introduced oxygen defects greatly affect the energy band structure. The band gap is slightly narrowed and the conduction band is raised, allowing O-NaNbO₃ to generate electrons with strong reducibility. Moreover, the oxygen defects reduced the work function of NaNbO₃, leading to increased charge separation in the bulk phase. The loaded Pt nanoparticles can further increase the surface charge separation via the formed Schottky barriers between Pt and O-NaNbO₃, which was thought to be the primary cause of the increased photocatalytic activity. Additionally, the oxygen vacancies and metal Pt also contribute to the adsorption and activation of N₂. Under the combined effect of the above changes, Pt/O-NaNbO₃ presents much higher photoactivity than NaNbO₃. The optimized NH₃ production rate reaches 293.3 μmol/L g^-1h^-1 under simulated solar light, which is approximately 2.2 and 20.2 times higher than that of O-NaNbO₃ and NaNbO₃, respectively. This research offers a successful illustration of how to improve photocatalytic N₂ fixation and may shed some light on how to design and construct efficient photocatalysts by combining several techniques.

Synthesis of Z-schemes 0D–3D heterojunction bi-functional photocatalyst with ZnInCuS alloyed QDs supported BiOI MF for H2O2 production and N2 fixation

Photocatalytic H2O2 and NH3 production on Zn–Cu–In–S QDs coupled with BiOI MFs via a Z-scheme charge transfer dynamic.