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A series of covalent organic frameworks (COFs) with β‐ketoenamine linkages named TpTt‐COF, TAPT‐COF, and TpPa‐1 were constructed for photocatalytic H2O2 generation in pure water and ambient air under visible light. Among them, TpTt‐COF performed striking H2O2 yield of 2647 μmol L−1, which is 3.5, 17.5, and 176.5‐fold those of TAPT‐COF, TpPa‐1, and bulk g‐C3N4, respectively, attributing to the electron‐deficient trait, short charge diffusion distance, and the narrowest bandgap of TpTt‐COF. Additionally, to achieve the facile recovery, TpTt‐COF was firmly and evenly anchored on melamine sponges (MS) because plenty of amino groups on the surface of MS could be involved in the β‐ketoenamine formation and guide the synthesis of TpTt‐COF on MS. The corresponding H2O2 evolution over this photocatalyst monolith is also respectable and can be well repeated at least four times. This work is quite instructive for photocatalyst construction based on covalent organic frameworks and facile photocatalytic applications. [ABSTRACT FROM AUTHOR]

Flower-like BiOI was decorated by CdS nanodots and followed by the introduction of iodine vacancies (V I) for photocatalytic sodium lignosulfonate (SLS) valorization under visible light. The iodine vacancies could adjust the band configuration, strengthen the light absorption and act as electron traps, while the intimate contact between BiOI and CdS nanodots provides a high-speed channel for charge transfer. As a consequence, the photocatalytic performance of SLS conversion into value-added vanillin was greatly improved over CdS/BiOI-V I compared with those of CdS, BiOI and CdS/BiOI. The highest yield of vanillin is 10.95 mg/g SLS over CdS/BiOI-V I , about 5, 8.7, 1.3 times those of CdS, BiOI, CdS/BiOI, respectively, and exceeding most related photocatalysts reported elsewhere. More significantly, as to the lignin from Masson pine and alkali lignin, the corresponding vanillin yield can reach 7.04 and 6.54 mg/g lignin , respectively, under the same condition, which suggests the great potential and universality for photocatalytic lignin valorization over such CdS/BiOI-V I heterostructure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Core-shell Bi-MOF@BiOX is fabricated by a one-pot solvothermal strategy. • The competitive coordination effect to Bi3+ makes BiOX and Bi-MOF contact closely. • Bi-MOF@BiOX has nice activities on Cr(VI), tetracycline and o-nitrophenol removal. • For above reactions, more than 13, 7, 5-time enhancements of activity are achieved. • Enhanced activities are observed for the treatment of mixed pollutants. Core-shell Bi-MOF@BiOX (X = I, Br and Cl) hybrids were fabricated by a one-pot solvothermal strategy via regulating the concentration and type of halogen ions in the Bi-based CAU-17 synthesis. By virtue of the competitive coordination effect to Bi3+ between CAU-17 and BiOX, CAU-17 was converted into another Bi-MOF with similar structures and compositions. Moreover, Bi3+ plays the role of "bridge" and endows an intimate interface contact between BiOX and the Bi-MOF, which immensely expedites the charge and mass transportation. The obtained Bi-MOF@BiOX hierarchical heterostructures were applied to photocatalytic elimination of solo and mixed pollutants (Cr(VI)/tetracycline and Cr(VI)/o-nitrophenol), and exhibited favorable performances. Choosing Bi-MOF@BiOI as a typical example, the corresponding performances for Cr(VI) reduction, tetracycline and o-nitrophenol degradation in their solo systems are 14, 10, 8 times higher than those of CAU-17, and 13, 7, 5 times higher than those of BiOI under visible light, respectively. Of note, the above photocatalytic performances could be further improved in the coexisting environment of Cr(VI) and tetracycline or o-nitrophenol, which is attributed to the elevated charge separation efficiency caused by the timely consumption of photo-excited electrons and holes. This work gives some insights into the delicate design of MOF photocatalysts and their applications in environmental restoration. [ABSTRACT FROM AUTHOR]

• BiOI/MIL-121 photocatalyst is constructed by a facile hydrothermal method. • BiOI/MIL-121 performs excellently for tetracycline degradation under visible light. • Free carboxyl in BiOI/MIL-121 can adsorb tetracycline through hydrogen bond. A series of BiOI/MIL-121(Al) hybrid photocatalysts has been prepared by a facile hydrothermal method. Two-dimensional BiOI sheets are intimately anchored on rod-like MIL-121 due to the electrostatic and coordination effects between Bi3+ and carboxyl. The BiOI/MIL-121(Al) hybrid exhibits favorable performances for visible-light-driven degradation of tetracycline. The degradation performance of the optimal sample BM-20 is more than twice as that of pure BiOI. Apart from the close contacts between BiOI and MIL-121, the hydrogen bond induced by carboxyl in MIL-121 promotes the adsorption of tetracycline, which is also conducive to the photocatalytic degradation process. Moreover, results show that photo-induced holes and superoxide radicals are both the main active species for the photocatalytic degradation of tetracycline over BiOI/MIL-121 composites. This work would inspire the materials design with specific functional groups for efficient (photo)catalytic reaction. [ABSTRACT FROM AUTHOR]

Zinc oxide–Graphitic carbon nitride (ZnO@g-C 3 N 4) composite membranes were prepared via in-situ growing ZnO crystals in the g-C 3 N 4 membrane. In this composite membrane, ZnO crystals were embedded in loose surface layers of g-C 3 N 4 membrane, which can repair some non-selective defects and improve the dye retention performance. In addition, the hetero-structures formed between ZnO and g-C 3 N 4 nanosheets promoted the separation of photogenerated electron-holes in g-C 3 N 4 layer, and improving the photocatalytic and anti-fouling performance of ZnO@g-C 3 N 4 composite membranes. Herein, the prepared composite membranes showed excellent dye removal performance and self-cleaning property in dynamic recirculation filtration systems under visible light irradiation. The optimized sample (CNZ-0.15 g) showed MB removal efficiency of 94.4% and water flux of 336.8 L.m−2.bar−1.h−1. The outcome of this research would suggest the application of graphitic nitride nanomaterials for developing highly efficient photocatalytic membranes. [Display omitted] • The ZnO@g-C 3 N 4 photocatalytic membranes were designed and fabricated. • The introduced ZnO particles repaired the defects in the pristine g-C 3 N 4 membrane. • The hetero-structure promoted the electron-hole separation in composite membranes. • The composite membranes showed efficient dye removal under continuous operation conditions. [ABSTRACT FROM AUTHOR]

Photocatalytic H 2 O 2 production by reducing O 2 has drawn great interest, but most reactions were conducted in pure O 2 which requires extra energy input. Here, TpPa-1 was facilely decorated by ZnIn 2 S 4 nanosheets for H 2 O 2 production in ambient air under visible light. Profiting from the hierarchical heterostructure, efficient visible-light absorption and O 2 capture of ZnIn 2 S 4 /TpPa-1, an H 2 O 2 yield of 516 μmol·L−1 was obtained with 2 h irradiation, which is 3.0 and 3.9 times those of blank TpPa-1 and ZnIn 2 S 4 , respectively. The intimate interface contact between ZnIn 2 S 4 and TpPa-1 also contributes to the performance improvement. It is noted that the photocatalytic H 2 O 2 formation over ZnIn 2 S 4 /TpPa-1 hybrids experienced an indirect reduction of O 2 that ·O 2 - served as the key intermediate. Additionally, the reactions under different atmospheres and ethanol concentrations demonstrate that both O 2 and ethanol play important roles in the efficient evolution of H 2 O 2. This work could enlighten the heterostructure construction and (photo)catalytic H 2 O 2 production based on covalent organic frameworks. [Display omitted] • ZnIn 2 S 4 /TpPa-1 was first constructed for photocatalytic H 2 O 2 evolution in air. • The H 2 O 2 yield is 3 and 3.9 time-enhancement than those of ZnIn 2 S 4 and TpPa-1. • Efficient visible-light absorption and O 2 capture lead to the high activity. • The H 2 O 2 formation over ZnIn 2 S 4 /TpPa-1 undergoes an indirect reduction of O 2. [ABSTRACT FROM AUTHOR]