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[Display omitted] • Nb 2 O 5 nanorods are synthesized with a specific surface area of 166 m2/g. • The dissociative adsorption of amine on Nb 2 O 5 affords a surface complex. • The surface complex can facilitate selective oxidation of amine to imine. • TEMPO+PF 6 − acts as an electron–proton transfer mediator. • Superoxide is the dominant reactive oxygen species. Cooperative photocatalysis has gained increasing interest to better an existing redox reaction with a mediator. Herein, an ingenious system is constructed for the visible light-driven selective oxidation of a variety of amines by merging niobium oxide (Nb 2 O 5) photocatalysis with an electron–proton transfer mediator, 2,2,6,6-tetramethylpiperidine-1-oxoammonium hexafluorophosphate (TEMPO+PF 6 −). The visible light-driven dissociative adsorption of amine over Nb 2 O 5 nanorods gives rise to an amine–Nb 2 O 5 complex with a weak response to visible light (λ < 460 nm). With adding 4 mol% of TEMPO+PF 6 −, the conversion of benzylamine over Nb 2 O 5 is approximately 2.5 times that without TEMPO+PF 6 −. The proton and electron transfer between the amine–Nb 2 O 5 complex and TEMPO+PF 6 − is the key to assuring cooperative photocatalysis. Besides, the oxidant dioxygen is predominantly reduced to superoxide anion in affording the imine products. This work highlights it is feasible to ameliorate selective organic conversions over metal oxide photocatalysts with a suited mediator. [ABSTRACT FROM AUTHOR]

Cooperative photocatalysis of 2H1NA-TiO 2 with TEMPO enables the highly selective aerobic oxidation of benzylamines. [Display omitted] Solar photocatalysis is the key to resolve many environmental challenges but is usually hard to achieve over a metal oxide semiconductor. Therefore, assembling π-conjugated molecules onto semiconductors becomes an efficient approach to solar conversion via ligand-to-metal charge transfer. Here, a rational design of ligands for titanium dioxide (TiO 2) is presented to produce robust visible light photocatalysts. Three hydroxynaphthoic acids (HNAs) were selected as ligands by extending an extra benzene ring of salicylic acid (SA) at 3,4 or 4,5 or 5,6 positions. These ligands could regulate the performance of TiO 2 in which 2-hydroxy-1-naphthoic acid (2H1NA) endows the best outcome. In detail, blue light-powered cooperative photocatalysis of 2H1NA-TiO 2 with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO, 5 mol%) inaugurates the expeditious formation of imines by oxidation of amines with atmospheric oxygen (O 2). Interestingly, the increase of the O 2 pressure from 1 atm to 0.4 MPa promoted the selective oxidation of benzylamine but thereafter declined with a further boost to 0.6 MPa. Notably, an electron transfer between the oxidatively quenched 2H1NA-TiO 2 and TEMPO is established, offering a new pathway for environmental applications. This work presents a strategy in designing cutting-edge visible light photocatalysts via altering semiconductors with surface ligands. [ABSTRACT FROM AUTHOR]

[Display omitted] Photodynamic therapy (PDT) is proved to be a promising modality for clinical cancer treatment. However, it also suffers from a key obstacle in association with its oxygen-dependent nature which greatly limits its effective application against hypoxic tumors. Herein, on the basis of the unique property of calcium peroxide (CaO 2), we propose an O 2 -self-supply strategy for the promotion of PDT by combining the in situ O 2 -generation characteristic of calcium peroxide with the photosensitive nature of porphyrin. A shell of ZIF-8 was synthesized surround the CaO 2 core to prevent the CaO 2 from premature decomposition and increased the loading of THPP efficiently. Depending on the in situ self-supply of O 2 , the photosensitizer was able to exhibit an enhanced PDT effect that significantly inhibit the growth of tumor. Moreover, the enrichment of free calcium ions derived from the decomposition of CaO 2 under acidic tumor microenvironment also shows the unique ion-interference effect and contributes to the obvious inhibition against tumor growth. This work presents a synergistic strategy for the construction of a photodynamic promotion/ion-interference combined nano-platform which can also serve as an inspiration for the future design of effective nanocomposites in tumor treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] Chirality-based nanomaterials, especially semiconductors nanoparticles (NPs), are the emerging research in biomedicine field. Herein, chiral manganese dioxide (L/D-MnO 2) NPs were synthesized by using threonine molecules as chiral ligands. Then cisplatin loaded L/D-MnO 2 (L/D-MnO 2 @Pt) NPs were successfully constructed based on the high specific surface area of L/D-MnO 2 NPs. L/D-MnO 2 @Pt NPs could be specifically internalized by tumor cells and efficiently deplete the glutathione (GSH) through redox reaction to release Mn2+ and Pt. The released Mn2+ exhibited strong chemodynamic effect through Fenton-like reaction. The depletion of GSH further improved the chemodynamic therapy (CDT) efficiency. The combination of the CDT of Mn2+ with the chemotherapy of Pt considerably enhanced the tumor therapy efficiency. It was particularly noteworthy that L/D-MnO 2 @Pt NPs showed chirality-based different internalization by tumor cells and further led to different tumor cell ablation effects, in which D-MnO 2 @Pt NPs exhibited stronger therapeutic efficiency than L-MnO 2 @Pt NPs. These findings provided deep insights for novel biomedical applications of chirality-based semiconductors NPs. [ABSTRACT FROM AUTHOR]

[Display omitted] Fe(III) coagulation-precipitation process has been widely used to remove heavy metals from industrial effluents; however, the influences of organic ligands on the sequestration of different heavy metals in the Fe(III)/metal-EDTA ternary system are not well understood. In this study, the pH-dependent mechanisms of CuII-EDTA and NiII-EDTA removed by in-situ formed iron (oxy)hydroxides were studied using surface complex modeling and a suite of characterization techniques. Results of surface complex model indicated that there should be minimal difference between removal of CuII-EDTA and NiII-EDTA by iron (oxy)hydroxides if adsorption was the dominant mechanism. However, through the speciation analysis and characterization of the precipitates generated after coagulation and precipitation, we have demonstrated that at neutral pH the complexation of Fe(III) and EDTA influenced the surface properties of iron (oxy)hydroxides formed, with the higher removal of Cu2+ (compared to Ni2+) contributed by its coprecipitation with Fe(III). Moreover, at basic pH, decomplexation of CuII-EDTA occurred on the iron (oxy)hydroxides surface with the released copper ions involved in the formation of (oxy)hydroxides. The low removal of nickel (from NiII-EDTA) was ascribed to the higher conditional stability constant of NiII-EDTA. Results of this study have advanced our understanding of the complicated interactions among Fe(III), organic ligands and heavy metals in the industrial effluents, and provide insight to optimization of the process efficiency. [ABSTRACT FROM AUTHOR]