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H2O2 production by photocatalysis has received considerable attention, while using MOF‐based materials as photocatalysts is still less explored. Ligand functionalization of MOFs is a decoration way at the molecular level, which provides the basis for the further modification of MOFs. In this concept, ligand functionalization of MOFs for photocatalytic H2O2 production has been systematically and extensively discussed. The strategies of ligand functionalization include grafting of functional groups (e. g. amino, methoxyl, boron and alkyl) and multiple ligand decoration. Correspondingly, some specific effects are achieved, e. g. improved charge carrier separation, enhanced O2 adsorption and hydrophobicity, which can realize efficient H2O2 production by photocatalysis. Meanwhile, reaction conditions and activities of photocatalytic H2O2 production have also been explicitly introduced in these studies. At last, the future perspectives are proposed. This concept sheds fresh light on the great potential of ligand functionalization of MOFs for photocatalytic H2O2 production. [ABSTRACT FROM AUTHOR]

Abstract: Selectivity of cascade redox reactions: the reduction of nitrobenzene to azoxybenzene and then to azobenzene and the oxidation of benzyl alcohol to benzaldehyde and then to benzoic acid, is discovered to be tuneable via light irradiation over plasmonic gold photocatalysts. The representative photocatalyst of Au/CeO2 was characterized by TEM, EDX, UV-Vis and XPS to determine its morphology, elemental composition, photo absorptivity and oxidation state of gold. The catalytic test results demonstrate that the net contribution of light irradiation correlates with the ability of incident light to excite electrons and light absorption of catalysts. These findings may inspire peer researchers in developing new photocatalytic processes or in designing new photocatalysts for clean chemicals synthesis.Graphical Abstract: [ABSTRACT FROM AUTHOR]

[Display omitted] • The whole advancement of MOF-based photocatalysts for H 2 O 2 production was discussed. • Diverse tailoring strategies on MOFs for H 2 O 2 production were summarized in detail. • H 2 O 2 production pathways, activities and reaction conditions were elucidated. • Outlooks on current challenges and emerging opportunities were presented. Photocatalytic synthesis of H 2 O 2 is currently in the spotlight because of its green and sustainable nature, but the construction of photocatalysts with high efficiency is still the key. In this regard, emerging photocatalysts based on metal–organic frameworks (MOFs) have been revitalized for the green synthesis of H 2 O 2 with the various acclaimed merits of MOFs. Therefore, this review provides an insight into the overall progress of MOF-based photocatalysts for H 2 O 2 production through various modification strategies on MOFs, including molecular-level decoration (ligand and metal center decoration, defect and facet engineering), heterostructure construction (C 3 N 4 /MOFs, metal sulfides/MOFs and metal oxides/MOFs) and derivatization (metal oxides/sulfides and carbonaceous materials). Meanwhile, the corresponding pathways (oxygen reduction reaction and water oxidation reaction), performances and reaction conditions for photocatalytic H 2 O 2 production were elucidated. Finally, outlooks on current challenges and emerging opportunities in this research field were presented. We hope this review will inspire and contribute to the future development of both MOF-based catalysts and H 2 O 2 green production. [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] A subtle flower-like MIL-125-NH 2 @BiOI was fabricated by a facile solvothermal method for simultaneously eliminating Cr(VI)/tetracycline mixed pollutants under visible light. The strong interaction between amino in MIL-125-NH 2 and Bi3+ of BiOI promotes the formation of this unique inlaid structure and enables the favorable contact between MIL-125-NH 2 and BiOI, thus accelerating the transfer of charge carriers. Remarkably, MIL-125-NH 2 @BiOI displays a superior activity compared with that of two monomers for the photocatalytic reduction of Cr(VI) and degradation of tetracycline. More significantly, the photocatalytic efficiency can be further boosted in the coexistence of Cr(VI) and tetracycline, which is 1.8 and 1.6 times that of single Cr(VI) and tetracycline, respectively. The synergistic effect between Cr(VI) reduction and tetracycline oxidative degradation can further facilitate the separation of photo-induced electrons and holes, resulting in the improved efficiencies in the Cr(VI)/tetracycline coexistent environment. This work sheds light on that MOF-based photocatalysts possess huge potential for practical environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] Pancake-like TiO 2 (M-TiO 2) derived from the metal-organic framework was inlaid into three-dimensional flower-like BiOI through a facile solvothermal method. M-TiO 2 supplies large surface area and mesoporous structure for attachment and transfer of the substrates and products, while BiOI acts as a photosensitizer to absorb visible light and generates electrons and holes. The distinct structure of M-TiO 2 /BiOI gives a favorable contact between the two monomers, and promotes the transfer of charge carriers. In conjunction with the proper band positions of M-TiO 2 and BiOI, the efficient separation of electron-hole pairs is attained. Benefiting from the above cooperative effects of M-TiO 2 and BiOI, the performance for the vanillin generation from sodium lignosulfonate (SLS) over M-TiO 2 /BiOI composites has a prominent improvement under visible light. Specifically, the yield over optimal M-TiO 2 /BiOI sample is about 5.8 mg/g SLS , obviously superior to that over pristine M-TiO 2 (~1 mg/g SLS) and BiOI (~1.1 mg/g SLS). It is found that h+ and O 2 – play the key role for vanillin generation from sodium lignosulfonate, and the low vanillin generation under UV–vis light sheds light on that OH is an adverse factor. We hoped that this work could inspire the studies on the photocatalytic valorization of biomass using noble metal-free catalysts. [ABSTRACT FROM AUTHOR]

Lignin is abundant and contains a large number of aromatic groups. Herein, Cd x Zn 1-x S photocatalyst with tunable band gap energy was successfully synthesized by using 3-mercaptopropionic acid as a structure tuning additive. Cd x Zn 1-x S can depolymerize alkaline lignin to vanillin by the photocatalytic process. Each gram of alkaline lignin can produce 46.5 mg of vanillin. 2-Phenoxy-1-phenylethanol (PP-ol) and other model compounds were used to understand the depolymerizing process of lignin. Fine tuned Cd x Zn 1-x S can effectively cleave the C β -O-4 bond existed in PP-ol under simulated sunlight. The highest conversion of PP-ol was 89.5% with phenol and acetophenone yields of 66.2% and 33.5%, respectively. The mechanism studies confirm that the C α -H in PP-ol and lignin is firstly dehydrogenated to form C α radical intermediates, and then the photogenerated electrons break the adjacent C β -O bond. This research provides a new strategy to prepare valuable chemicals by virtue of renewable biomass and simulated sunlight. [ABSTRACT FROM AUTHOR]

Catalytic conversion of lignin to certain aromatic compounds has been extensively studied but still has great challenges. Photocatalytic depolymerizing lignin is a very promising method to obtain valuable chemicals. Herein, Zn 4 In 2 S 7 (ZIS)-based photocatalyst was successfully synthesized by simply combining ZIS and graphene oxide (GO). Photocatalyst ZIS-100 can efficiently depolymerize organosolv lignin into phenols and ketones. The relative content of valuable compounds in the depolymerized product was increased by 2.5 times as compared that without photocatalyst. The photocatalyst can effectively break C β -O bonds in 2-phenoxy-1-phenylethanol (PP-ol, a model compound) and the conversion of PP-ol is 93.27%. Mechanism studies show that the thiol groups on the surface of ZIS-100 play an important role in the formation of C α radical intermediates. Photocatalytic cleavage of C β -O bond mainly follows a one-step reaction mechanism through a self‑hydrogen transfer process. This study provides a new strategy for selectively breaking C β -O bond in lignin to form valuable chemicals. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ti-MOFs decorated by Pt or Au NPs with sizes of 3–9 nm have been synthesized. • Pt/MIL-125-NH 2 showed highest photocatalytic activity for alcohol oxidation. • M/MIL-125-NH 2 exhibited much better photocatalytic activity than that of M/MIL-125. Abstract Metal nanoparticles (NPs) decorated MOFs for photocatalysis has drawn enormous attention in the past decade. Here, a series of M/Ti-MOFs (M = Pt and Au, Ti-MOFs = MIL-125-NH 2 and MIL-125) has been synthesized through a facile post-synthetic method and the metal NPs highly dispersed on surface of MOFs with major sizes of 3–9 nm. Light absorption edges of scaffolds are crucial in the photocatalytic oxidation of benzyl alcohol over M/MIL-125-NH 2 and M/MIL-125. The conversion of benzyl alcohol over Pt/MIL-125-NH 2 is 2.4 times and 1.9 times higher than that of pristine MIL-125-NH 2 and Au/MIL-125-NH 2 , respectively. Besides, Pt/MIL-125-NH 2 photocatalyst also exhibited good activity for Cr(VI) reduction compared to that of MIL-125-NH 2. The enhanced photocatalytic activity of Pt/MIL-125-NH 2 is contributed to the rapid transfer of photo-induced electrons and decreased recombination of electron-hole pairs, which is verified by measurements of photocurrent and Electrochemical Impedance Spectroscopy. We hope that this study will provide worthy information for designing metal/MOFs or metal/MOFs-NH 2 photocatalysts. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Noble metal nanoparticles (NPs) functionalized MOFs are attractive materials for photocatalytic reactions, and outstanding catalytic performances can be expected, especially when they have intrinsically matched crystal faces between metals and MOFs. This study discovered that the photocatalytic oxidation of aromatic alcohols to aldehydes was enhanced over Au/UiO-66-NH 2 or Au/UiO-66 but suppressed over Pt loaded counterparts, whereas the reduction of Cr(VI) was boosted over both two catalysts. In reactions, the conversion of benzyl alcohol was 17.1% over UiO-66-NH 2 and 7.6% over UiO-66, and an enhanced conversion was obtained over Au/UiO-66-NH 2 (30.5%) and Au/UiO-66 (24.1%). However, the conversion was decreased over Pt/UiO-66-NH 2 (9.3%) and Pt/UiO-66 (<1%). Experimental results revealed strong correlations between Zr-MOFs and loaded metal NPs, as Zr centers promoted the formation of Pt(200) planes that suppressed the production of ·O 2 − intermediates to oxidize aromatic alcohols, whereas Pt(200) exhibited no effect on the Cr(VI) reduction triggered by photo-induced electrons. The findings in this study on constructing noble metal NPs functionalized Zr-MOFs catalysts with specially-matched crystal structures and on distinguishing photocatalytic mechanisms on oxidation of alcohols and reduction of Cr(VI) would provide valuable information for designer (photo)catalysts based on MOFs and their applications in such as catalysis and environmental remediation. [ABSTRACT FROM AUTHOR]

Abstract In this study, homogeneous alloy Au Pt nanoparticles were successfully immobilized on ultrathin TiO 2 nanorods via a facile photodeposition technique. The Au Pt/TiO 2 hybrid exhibited high photocatalytic activity and stability during the selective photosynthesis of benzaldehyde from benzyl alcohol under visible light. The optimal performance was obtained with the Au 1 Pt 1 /TiO 2 sample, which had a benzyl alcohol conversion rate of 65.3%. The engineered TiO 2 nanorods (304 m2/g) can be employed as a stabilizing matrix and an excellent dispersant for noble metal particles. Moreover, the formation of the alloy structure substantially enhances the photoinduced carrier separation efficiency compared with loading Au or Pt alone on TiO 2. The bimetallic nanoparticles exhibited the properties related to the individual metals, as well as new properties due to synergistic effects of the electron-accumulating function of Pt and the surface plasmon resonance of Au. Graphical abstract Image 1 Highlights • Au Pt alloy successfully immobilized on ultrathin TiO 2 nanorods. • Au Pt/TiO 2 exhibited enhanced photocatalytic performance and good stability. • Benzyl alcohol conversion rate was 65.3% in the presence of Au 1 Pt 1 /TiO 2. [ABSTRACT FROM AUTHOR]

The delicate design of photocatalyst monoliths is of great significance for the practical applications of artificial photocatalysis. An in-situ synthesis to prepare ZnIn 2 S 4 /cellulose foam was developed. Cellulose is dispersed in a highly concentrated ZnCl 2 aqueous solution to prepare Zn2+/cellulose foam. Zn2+ ions are pre-anchored by hydrogen bonds on cellulose and become in-situ sites for synthesizing ultra-thin ZnIn 2 S 4 nanosheets. This synthesis method makes ZnIn 2 S 4 nanosheets and cellulose tightly bound and prevents ZnIn 2 S 4 nanosheets from stacking in multiple layers. As a proof of concept, the prepared ZnIn 2 S 4 /cellulose foam exhibits a favorable performance for photocatalytic reduction of Cr(VI) under visible light. By adjusting the concentration of zinc ions, the optimal ZnIn 2 S 4 /cellulose foam is capable to completely reduce Cr(VI) in 2 h and the photocatalytic activities show no decrease after 4 cycles. This work could inspire people to build floating cellulose-based photocatalysts via in-situ synthesis. [Display omitted] [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]

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]

A novel and highly efficient photocatalyst of Cd 0.5 Zn 0.5 S@ZIF-8 nanocomposite has been developed by a facile self-assembly strategy. This is the first report on the application of Cd x Zn 1−x S and metal-organic framework (MOF) nanocomposite as photocatalysts for the reduction of Cr(VI). The resulting Cd 0.5 Zn 0.5 S@ZIF-8 exhibited higher photocatalytic activity than that of pristine Cd 0.5 Zn 0.5 S and ZIF-8. Particularly, the CZS@Z60 composite with 60 wt% of ZIF-8 exhibited a photocatalytic activity that is about 1.6 times as high as that of Cd 0.5 Zn 0.5 S. The dominant reason for the improved photocatalytic reduction potential is proved to be the newly-formed interfacial S Zn bonds that firmly connect Cd 0.5 Zn 0.5 S and ZIF-8 and substantially improve the separation efficiency of photo-excited electrons and holes. The newly-formed chemical bonds are confirmed by XPS analyses, and the prolonged lifetime of photo-excited electrons is evidenced by the electrochemical measurement of photocurrent, which shows that the photocurrent on Cd 0.5 Zn 0.5 S@ZIF-8 is much higher than that of Cd 0.5 Zn 0.5 S and ZIF-8. This study clearly demonstrates that the MOF-based composite nanomaterials hold great promises for applications in the field of environmental remediation and for design of novel photocatalytic materials. [ABSTRACT FROM AUTHOR]

The reduced graphene oxide (RGO) loaded Zn 0.5 Cd 0.5 S nanocomposite has been successfully prepared by a facile solvothermal method. The as-prepared photocatalysts were characterized by a combination of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and N 2 absorption-desorption. The Zn 0.5 Cd 0.5 S@RGO composites with a RGO content of 0.5 wt% (GS-0.5) showed the highest photocatalytic activity for the degradation of various dyes (methylene blue, methyl orange and Rhodamine B), which is mainly due to the uniform dispersion of nanoparticles on RGO sheets and the enhanced separation rate of photo-induced electrons and holes. The GS-0.5 photocatalyst can be repetitively used without significant loss of activity. This new material holds great promise for applications in the field of water purification as well as optoelectronic fields at a large scale. [ABSTRACT FROM AUTHOR]

A facile and simple method was offered to synthesize porous N-doped ZnO via direct calcination of urea and ZIF-8 mixture. From XRD and XPS analysis, nitrogen has been successfully incorporated into ZnO lattices without introducing other N-containing or Zn-containing phases. Such nitrogen doping can enhance the visible-light harvesting ability and inhibit the recombination rate of electron-hole pairs; as a result, improved visible-light driven photocatalytic activity was achieved in N-doped porous ZnO and the photocatalytic activity of N-doped ZnO is 2.58 times higher than that of ZIF-derived pure ZnO. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen vacancies-rich Bi 2 MoO 6 nanoflakes were facilely anchored on MIL-121. • The oxygen vacancies can highly accelerate the charges transfer and separation. • Vo-BMO/M is more efficient than Bi 2 MoO 6 , MIL-121 and Bi 2 MoO 6 /MIL-121. • Vo-BMO/M can efficiently photocatalytic removal of mixed Cr(VI)/2-nitrophenol. Oxygen vacancy-rich Bi 2 MoO 6 nanoflakes were uniformly anchored on cuboid MIL-121 via benign solvothermal and thermal-reduction methods. Benefiting from the efficient light capture and rich electron traps triggered by oxygen vacancies, intimate interface contact and intrinsic heterostructure, the enhanced separation and transportation rates of photo-induced charge carriers are achieved. Consequently, Bi 2 MoO 6 /MIL-121 with rich oxygen vacancies performs excellent photocatalytic activities, which are 4.8, 7.1, 1.4 times higher for Cr(VI) reduction, and 6.1, 5.4, 1.2 times higher for 2-nitrophenol degradation compared with those of Bi 2 MoO 6 , MIL-121 and Bi 2 MoO 6 /MIL-121 without oxygen-vacancies, respectively. Furthermore, thanks to the timely consumption of photo-induced electrons and holes by Cr(VI) reduction and 2-nitrophenol degradation, respectively, the corresponding photocatalytic efficiencies are further boosted in their coexistent environment. This work would enlighten the design of metal-organic framework-based (photo)catalysts for the treatment of complicated pollution. [ABSTRACT FROM AUTHOR]

N-doped titania is prepared using ethylenediamine as the nitrogen source by a sol–gel method. The preparation conditions, such as the volume ratio of ethylenediamine to sol, and the heat temperature on the nitrogen doping are systematically examined. UV results indicate the N-doped TiO 2 catalysts have enhanced absorption in the visible light region, and exhibit high activities on the visible light photocatalytic reactions to the hydrogen production and methyl orange degradation. X-ray diffraction (XRD) and FT-IR results reveal that N species have been incorporated into the TiO 2 lattice at a high N-doping level. N-doped titania prepared with an ethylenediamine to sol volume ratio of 1:1 and sintering temperature of 500 °C performed the highest hydrogen production rate (2.98 mmol g −1 h −1 ) and best methyl orange degradation performance. A conceivable structure change of N-doped TiO 2 sintered at different temperature was proposed. [ABSTRACT FROM AUTHOR]

MIL-101(Cr)@ZnIn 2 S 4 hierarchical heterojunction was delicately designed and fabricated through the in-situ growth of ZnIn 2 S 4 on MIL-101 and electrostatic self-assembly. It is affirmed that the Cr–S interface bonding between MIL-101 and ZnIn 2 S 4 in their composite was established based on the characterization results of X-ray photoelectron spectroscopy, Raman and zeta potential. Thus, a high-speed channel for charges transfer is offered due to the Cr–S bond, intimate interface contact and hierarchical structure of MIL-101@ZnIn 2 S 4 , which largely inhibits the recombination of photo-induced charge carriers and promises a remarkable photocatalytic activity. Choosing visible-light-driven reduction of Cr(VI) as a model, the optimal MIL-101@ZnIn 2 S 4 sample can reduce 95% of Cr(VI) within 30 min, corresponding to a rate constant of 0.107 min−1, which is 2.9-fold compared with blank ZnIn 2 S 4 counterpart (MIL-101 has a negligible performance). Additionally, a conspicuous apparent quantum yield of 9.7% can be achieved at a wavelength of 420 nm. Eventually, to reinforce the practicability of MIL-101@ZnIn 2 S 4 , the composite powders were manufactured as aerogels utilizing bacterial cellulose as a substrate. The MIL-101@ZnIn 2 S 4 aerogel still exerts an enviable performance for photocatalytic reduction of Cr(VI) and stability. This work could inspire the material design and environmental remediation based on MOFs. [Display omitted] • MIL-101@ZnIn 2 S 4 hierarchical heterojunction with Cr–S bonds was delicately designed. • A high-speed channel for charges transfer is presented over MIL-101@ZnIn 2 S 4. • Efficiently photocatalytic reduction of Cr(VI) is achieved over MIL-101@ZnIn 2 S 4. • Aerogel was prepared from powder to improve the practicability of MIL-101@ZnIn 2 S 4. [ABSTRACT FROM AUTHOR]

• This work reports highly crystalline S-doped CNNTs with tunable geometry. • S-CNNTs-20 exhibit an enhanced visible-light photocatalytic N 2 fixation rate. • High crystallinity and S-N coordination firmly stabilize the surface N in S-CNNTs-20. • The synergistic effect is due to high crystallinity, S dopant and holey tubular form. Highly crystalline carbon nitride nanotubes doped with sulfur (S-CNNTs) were obtained from a facile co-polymerization of thiourea and melamine precursors. The geometry, crystallinity and the doped S content in CNNTs can be fine-tuned by varying the content of thiourea. Under the addition of 20 wt% thiourea, the resulting highly condensed S-CNNTs have a diameter of around 20 nm with mesopores on the tube wall, presenting an optimal visible light photocatalytic ammonia yield rate of 0.64 mM g cat –1h−1 with an apparent quantum efficiency of 5.65% at 420 nm. The surface N atoms in the optimal photocatalyst can be firmly stabilized due to the increased crystallinity and S-induced coordination. The high crystallinity and one-dimensional mesoporous structure promote the electron transfer along the longitudinal dimension, facilitate mass transport and extend visible light harvesting. The mesoporous nanotubes favor the exposure of S dopant active sites for the chemisorption and activation of nitrogen molecules. Moreover, the photoreduction ability is improved due to the upshifted conduction band level after S doping. The designed structure maximizes the utilization of the synergistic effect, thereby improving the photocatalytic activity. This work may provide a reliable and promising way to regulate the morphology and electronic structure of tubular CN for highly efficient photocatalysis via a nonmetal doping approach. [ABSTRACT FROM AUTHOR]

In recent years, organic-inorganic composites have aroused considerable attention due to their tunable properties, where cellulose tailored semiconductors for artificial photocatalysis are typical examples. In virtue of the unique fibrous structure and abundant surface functional groups, cellulose employed in the design of photocatalysts could endow good hydrophilicity, dispersity, stability, high porosity, conductivity, large surface area and even unexpected morphologies. In this review, the modification strategies of cellulose to semiconductors (function as assistants and sacrifice as bio-templates), diverse monoliths (films, gels and textiles) and their photocatalytic applications (contaminants treatment and H 2 production) are summarized in detail. In addition, the challenges and outlook of semiconductor/cellulose photocatalysts are also discussed. • Cellulose tailored semiconductors for photocatalysis were summarized in detail. • Two strategies including cellulose as assistant and bio-template were introduced. • Diverse semiconductor/cellulose photocatalyst monoliths were depicted. • Various photocatalytic applications over semiconductors/cellulose were described. [ABSTRACT FROM AUTHOR]

Highlights: [•] Preparation of aliphatic pinacol for the first time in an aqueous solution at room temperature. [•] Photocatalytic C C coupling reaction using isopropanol as the starting material. [•] Phase and pore structure modulation of commercial TiO2 by calcination. [Copyright &y& Elsevier]

Ultrathin ZnIn 2 S 4 (ZIS) nanosheets were coated on g-C 3 N 4 (CN) nanotubes to form CN@ZIS heterojunction as a high-performance photocatalyst for Cr(VI) reduction. Well-dispersed ZIS nanosheets on CN nanotubes favor the better utilization of light and the hierarchical pores promote the mass diffusion. Additionally, such in-situ growth of ZIS on CN nanotubes enables the formation of intimate interfacial contact between them and the obtained CN@ZIS displays a low recombination rate of photo-generated electron-hole pairs compared to the pristine CN and ZIS. Benefiting from these structural and compositional advantages, CN@ZIS exhibits a satisfactory photocatalytic Cr(VI) reduction efficiency and can reduce 30 mg/L Cr(VI) within 10 min (catalyst loading: 1 mg/mL) under visible-light irradiation. Such excellent performance makes CN@ZIS great potential in photocatalysis. [Display omitted] • ZnIn 2 S 4 nanosheets are grown on g-C 3 N 4 nanotube to form CN@ZIS heterojunction. • CN@ZIS exhibits structural and compositional advantages. • CN@ZIS exhibits excellent photocatalytic Cr(VI) reduction performance. [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]

Mesoporous TiO 2 with regular pancake-like morphology was synthesized by facile calcination of MIL-125 (MIL = Materials of Institut Lavoisier) at different temperatures. The optimal sample MT400 (calcination at 400 °C) is composed of nanoparticles with a size of about 10 nm and mesopores of about 4–12 nm. Its specific surface area can reach up to 174 m2 g−1. In the photocatalytic conversion of sodium lignosulfonate, the yield of vanillin over MT400 is 2.1 mg/g, obviously superior to that over P25 TiO 2 (0.27 mg/g). MT400 with a large specific surface area offers sufficient active sites, and its mesoporous structure provides pathways for the transport of charge carriers and products, giving a satisfactory photocatalytic performance for vanillin generation. It is proved that h+ and ·O 2 − play the key role for vanillin generation from sodium lignosulfonate. This work indicates that MOF-derived metal oxides hold great promise in the application of biomass (photo)catalytic valorization. [Display omitted] • A pancake-like mesoporous TiO 2 was synthesized by the calcination of MIL-125. • MT400 is composed of particles with a size of ca. 10 nm and mesopores of 4–12 nm. • The yield of vanillin over MT400 is 7.7-fold higher than that of P25. • The structure is helpful to the transport of charge carriers, substrates and products. [ABSTRACT FROM AUTHOR]

• Bi 2 S 3 /BiOCl@ZnIn 2 S 4 composite with Bi 2 S 3 as transition layer was constructed. • Bi 2 S 3 /BiOCl@ZnIn 2 S 4 shows high activities on Cr(VI) photocatalytic reduction. • The efficiency is 3.3 and 24.1 times as high as that of ZnIn 2 S 4 and Bi 2 S 3 /BiOCl. • The intimate heterostructure causes the boosted photocatalytic activity. Delicate construction based on 2D epitaxial heterostructure can be an effective route to adequately excavate and utilize its superiorities. Here, a core-shell Bi 2 S 3 /BiOCl@ZnIn 2 S 4 hierarchical heterostructure is rationally designed and built by Bi 2 S 3 epitaxial growth on two-dimensional template-like BiOCl and ZnIn 2 S 4 nanosheets in-situ growth. The epitaxial growth of Bi 2 S 3 on BiOCl endows the tight contact between them. More importantly, Bi 2 S 3 as the interlayer could offer an extra intimate junction to ZnIn 2 S 4 due to the chemical interaction of S2− between Bi 2 S 3 and ZnIn 2 S 4. Such a Bi 2 S 3 /BiOCl@ZnIn 2 S 4 composite was explored for visible-light-driven reduction of Cr(VI), and much satisfactory performance was achieved, which is about 3.3 and 24.1-fold increase compared to that of ZnIn 2 S 4 and Bi 2 S 3 /BiOCl respectively. Efficient generation, separation and transfer of photo-generated charge carriers inherited from this ternary hierarchical composite made significant contributions to the highly elevated photocatalytic activity. This work may stimulate the construction of multiple hierarchical composites based on 2D epitaxial heterostructure material for efficient photocatalysis or other optoelectronics. [ABSTRACT FROM AUTHOR]

• Cd x Zn 1-x S/ZnO nanocomposites were readily fabricated via a facile one-pot method. • The Cd/Zn molar ratios were tuned by altering the amounts of Na 2 S and Na 2 S 2 O 3. • Cd x Zn 1-x S/ZnO showed glorious performance on photocatalytic reduction of Cr(VI). • Cd 0.68 Zn 0.32 S/ZnO nanoparticles have tiny diameters of about 5−8 nm. Cd x Zn 1-x S/ZnO nanohybrids were fabricated by using mixed Na 2 S and Na 2 S 2 O 3 as the sulfur source via a facile one-pot synthesis. Cd x Zn 1-x S/ZnO with x = 0.54, 0.58, 0.62, 0.68 and 0.75 was successfully tuned by altering the molar ratio of Na 2 S and Na 2 S 2 O 3. Sole sulfur source Na 2 S or Na 2 S 2 O 3 could only generate Cd 0.5 Zn 0.5 S or CdS/ZnO, respectively. The in-situ co-growth of Cd x Zn 1-x S and ZnO makes them combine penetratingly in Cd x Zn 1-x S/ZnO nanohybrids, giving them a highly intimate contact. The natural matched band-edge positions and highly intimate contacts between Cd x Zn 1-x S and ZnO are conductive to charge separation and transfer. Benefiting from the structural and compositional merits, the optimized Cd x Zn 1-x S/ZnO nanohybrid with sizes of about 5−8 nm exhibited outstanding performance for Cr(VI) reduction under visible-light illumination. The newly designed one-pot synthetic strategy in this work may provide a brand-new pathway in developing high-efficiency multi-component photocatalysts for practical use. [ABSTRACT FROM AUTHOR]

• PEGylated deep eutectic solvent is used for mild synthesis of CdS. • Core-shell CdS@CeO 2 photocatalyst was successfully synthesized. • The degradation of tetracycline is as high as 91.5% by optimal photocatalyst. • CeO 2 coating helps effectively reduce the photo-corrosion. As ionic liquid analogues, deep eutectic solvents (DESs) have been widely used in many fields in past decades. In this work, a PEGylated deep eutectic solvent (PEGylated DES) was used for the solvothermal synthesis of CdS@CeO 2 core-shell material for the first time. The amount of CeO 2 coating has a remarkable influence on the photocatalytic degradation of tetracycline. When the molar ratio of CeO 2 to CdS is 1:1, the degradation rate of tetracycline is 91.5% under visible light (λ > 420 nm), which is about 1.57 and 10.5 times as that of CdS and CeO 2 , respectively. The enhancement of photocatalytic performance is due to the fast separation of photogenerated electrons, the lower recombination of electron-hole pairs and the smaller band gap, which are demonstrated via UV–vis diffuse, photocurrent density, electrochemical impedance spectroscopy, photoluminescence and Mott-Schokkty measurements. This work provides a new way for the design of a core-shell metal sulfide photocatalyst that can be used in environmental remediation. [ABSTRACT FROM AUTHOR]

Industrial effluents often contain mixed metal ions and dyes, and it is difficult to efficiently remove both types of contaminants simultaneously. Here, MIL-125-NH 2 @Ag/AgCl composites were for the first time developed through a facile deposition-photoreduction method for simultaneously removing Cr(VI)/Rhodamine B (RhB)/Malachite Green (MG) ternary system pollutants under visible-light irradiation. The capacities of Cr(VI) reduction dramatically increased to 98.4% in the coexistence of RhB and MG compared to that of binary (Cr(VI)/RhB (69.6%) or Cr(VI)/MG (67.5%)) and single Cr(VI) (29%) systems. In the meantime, the degradation efficiencies of dyes especially RhB in the ternary system were also improved compared to that of their individual systems. On the grounds of all the experimental results, it can be concluded that the efficient light-harvesting and electrons migration in MIL-125-NH 2 @Ag/AgCl and the synergistic effect of redox reactions between Cr(VI) and dyes hinder the recombination of photo-induced electron-hole pairs, which are responsible for their high photocatalytic activity to eliminate the mixed pollutants. This study provides a new route to construct high-performance photocatalysts for the practical treatment of wastewater containing mixed pollutants. • Photocatalytic Cr(VI) reduction highly enhanced as MIL-125-NH 2 combined with Ag/AgCl. • Cr(VI) reduced capacities improved 3.4 times in the coexistence of RhB and MG. • Dyes degraded activities also increased in the presence of Cr(VI). • Efficient light-harvesting, charge transfer and synergistic effect of redox cause it. [ABSTRACT FROM AUTHOR]