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The Co@BN core–shell structure boosts dye-sensitized photocatalysis under shell by confined effect and improvement of the tandem electron transfer. • High EY-sensitized photocatalytic hydrogen evolution activity was achieved. • Enhanced adsorption of EY and Co/BN Schottky junction promotes the electron transfer. • The confined space was a nanoreactor boosting the reduction of H+ to H 2 under shell. • The magnetic recyclability makes Co@BN favorable for its practical application. The Co@BN core–shell nanostructure of Co core and boron nitride (BN) shell was prepared through a facile one-step thermal treatment. The as-prepared Co@BN nanocomposites exhibited excellent dye-sensitized photocatalytic hydrogen evolution activity (13.78 mmol h−1 g−1) with visible light and the apparent quantum yield was 1.15%. The enhanced adsorption of EY on the BN shell and the Co/BN Schottky junction facilitate the tandem transfer of photo-generated carriers to the Co surface. Moreover, the core–shell interface serves as a nanoreactor boosting the reduction of H+ to H 2 on the Co surface. Additionally, the magnetic recyclability makes Co@BN favorable for its practical application. This work extends the application of the "photocatalysis under shell" and has potential in dye-sensitized solar cell. [ABSTRACT FROM AUTHOR]

[Display omitted] • SubPc-3/Ag 3 PO 4 direct S -scheme supramolecular semiconductors were successfully fabricated. • Photocatalytic performance of SubPc-3/Ag 3 PO 4 for organic pollutants improved obviously. • Experimental and theoretical demonstrated the electron transfer mechanism between SubPc-3 and Ag 3 PO 4. • Photodegradation pathways were proposed based on DFT and experimental results. This study demonstrates the successful construction of a hybrid van der Waals heterostructure (vdWH) consisting of 3D supramolecular networks and 2D semiconductor Ag 3 PO 4 , using hydrogen-bonded 3D networks H 12 SubPcB-OPh 2 OH self-assembled onto Ag 3 PO 4. The resulting organic/inorganic vdWH exhibits significantly enhanced photocatalytic degradation efficiency for oxytetracycline (OTC) and tetracycline (TC) under visible light irradiation, with apparent rate constants 1.8 and 1.5 times higher than those of pristine Ag 3 PO 4 , respectively. Moreover, after five photocatalytic cycles, the photocatalytic activity of vdWH was still much higher than that of pristine Ag 3 PO 4. Molecular dynamics simulations indicate that the SubPc-3 supramolecular assembly is more prone to forming a 3D hydrogen bonding network rather than a 1D columnar stacking. In-situ irradiated X-ray photoelectron spectroscopy analyses and theoretical calculations confirm that the charge transfers between H 12 SubPcB-OPh 2 OH and Ag 3 PO 4 are consistent with the S-scheme mechanism. This work provides a promising strategy for designing and fabricating efficient and stable supramolecular self-assembled semiconductor-based photocatalysts. [ABSTRACT FROM AUTHOR]

Ternary heterojunction CN/TiO 2 -Ti 3 C 2 constructed by CN and partially oxidized Ti 3 C 2 MXene exhibits excellent performance for visible-light photocatalystic NOx removal. [Display omitted] • Ti 3 C 2 MXene can be turned to TiO 2 -Ti 3 C 2 nanosheet by partially oxidation. • Ternary heterojunction catalyst was formed by g-C 3 N 4 and partially oxidized Ti 3 C 2. • NO conversion on the catalyst is inferred to S-scheme heterojunction mechanism. • NO removal efficiency of the photocatalyst reaches up to 66.3% under visible light. Highly efficient composite photocatalysts were prepared through annealing partially oxidized Ti 3 C 2 MXene with melamine under N 2 flow. The two-dimensional Ti 3 C 2 MXene was aforehand partially oxidized to form TiO 2 -Ti 3 C 2 nanosheet by precisely controlling the oxidation conditions. Ternary g-C 3 N 4 /TiO 2 /Ti 3 C 2 MXene photocatalyst was constructed by coating melamine derived g-C 3 N 4 on TiO 2 -Ti 3 C 2 nanosheet. The photogenerated electron-hole separation was significantly enhanced by the S-scheme heterojunction. Ti 3 C 2 tightly bonded with TiO 2 benefits transfer and aggregation of photo-induced holes. The composite material has an interconnected nanosheet structure, which increases the absorption of light and the reaction interface between gaseous reactant and photocatalysts. When evaluated as NOx purification photocatalysts, the fabricated composites get the high NO removal efficiency and low NO 2 generation. Under visible light, NO removal efficiency of the composite photocatalyst can reach up to 66.3%, which is significantly better than the g-C 3 N 4 or TiO 2 -Ti 3 C 2. This work demonstrates that moderately oxidized Ti 3 C 2 MXene is a good candidate for the construction of high-performance air purification photocatalysts. [ABSTRACT FROM AUTHOR]