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The construction of heterojunctions is often considered an effective strategy for achieving visible light driven photocatalytic degradation of organic pollutants. In this work, defective g‐C3N4 ultrathin nanosheets were synthesized via alkaline etching method. Subsequently, a S‐scheme heterojunction was constructed between the contact interface of ZnO nanorods and alkaline C3N4 (aC3N4) to promote the electron transfer, resulting in a novel piezo‐photocatalyst (aC3N4/ZnO). The piezo‐photocatalytic performance of aC3N4/ZnO samples with different ratios was studied by adjusting the addition amount aC3N4. In addition, optimum 7 %‐aC3N4/ZnO samples exhibited the highest piezo‐photocatalytic degradation activity under light and ultrasonic irradiation with MB as the target pollutant, exhibiting the 99.89 % degradation rate and 65.68 % mineralization rate within 50 minutes. The capture experiments showed that 1O2,⋅O2− and ⋅OH were active substances in promoting the performance of piezo‐photocatalysis. The mechanism studies indicated that the enhanced piezo‐photocatalytic activity can be attributed to the synergistic effect of the piezoelectric properties of ZnO and the S‐scheme heterojunction formed at the aC3N4/ZnO interfaces, which provides power for the separation and transport of electron and hole. This work highlights the importance of carefully construction S‐scheme heterojunction and defective structures to precisely understand the catalytic properties, benefiting catalytic design and development. [ABSTRACT FROM AUTHOR]

Designing new materials that can be used to treat environmental pollutants is one of the prime focuses of chemical science. Here, an unprecedented photocatalytic material with high activity of catechol sensitized ZnTiO3/TiO2/ZnO hollow microspheres was synthesized by hydrothermal method. The structure and properties of the composite photocatalyst were analyzed by various testing methods. The photocatalytic activity was evaluated by using methylene blue (MB) as the target degradation substance. The results demonstrated that catechol (CA) sensitized ZnTiO3/TiO2/ZnO photocatalyst is a hollow microsphere with a diameter of 1–1.5 mm, the CA molecules are covalently bonded to the ZnTiO3/TiO2/ZnO surface, and the composite photocatalyst has good light absorption and carrier separation performance. Under the condition of irradiation for 90 min, the degradation rate of the composite photocatalyst for MB was higher than that of ZnTiO3/TiO2/ZnO. When the loading amount of CA was 0.6 wt%, the degradation rate of CA/ZnTiO3/TiO2/ZnO for MB was as high as 98.28 %, and the reaction rate constant was up to 4.35×10−2 min−1. A reasonable mechanism of photocatalytic degradation of pollutants by catechol as sensitizer on ZnTiO3/TiO2/ZnO was proposed. This study provides a theoretical reference for efficient photodegradation of pollutants in the environment. [ABSTRACT FROM AUTHOR]

We aimed to construct a method involving the photocatalytic oxidative dehydrogenation of formic acid (FA) to promote the acetone reductive hydrogenation of C–C coupling, where photo-electrons and photo-holes could be effectively used. The results showed that the conversion rates of acetone and FA in the g-C3N4 photocatalytic acetone–FA coupling reaction system were 88.74% and 60.82%, respectively. Further research showed that the Na+ concentration on the surface of the C3N4 photocatalyst was also positively correlated with pinacol selectivity. The g-C3N4 treated with 5 M NaOH showed a high pinacol selectivity of 60.87%, which was increased by 32.30%. [ABSTRACT FROM AUTHOR]

In this work, a series of novel SnO2/ZnO nanocomposites with different morphologies were fabricated via a facile hydrothermal technique followed by calcination in air. The morphological, structural and photocatalytic properties of the SnO2/ZnO nanocomposites were studied using different methods. The results showed that the synthesized nanocomposites possessed crystal phases of wurtzite hexagonal phase ZnO and tetragonal rutile phase SnO2. In addition, the morphologies of SnO2/ZnO nanocomposites strongly depended on the molar ratios of Sn and Zn. Compared with ZnO and SnO2, the SnO2/ZnO nanocomposites exhibited considerably higher degradation efficiency for the photodegradation of methylene blue and quinolone antibiotics under mercury lamp irradiation. The SZ‐2 nanospheres exhibited the highest degradation efficiency of 95.81%, which was about 2.63 times higher than that of ZnO nanoparticles. Moreover, the trapping experiments confirmed that ˙OH played the dominant role in MB degradation. Finally, the charge carriers potential transfer pathway and photocatalytic degradation mechanism were put forward. This study provides an economical way to prepare hybrid nanocomposites with controlled morphology for practical applications in the photocatalytic degradation of organic dyes and residual antibiotics. [ABSTRACT FROM AUTHOR]

If a sacrificial agent is selectively oxidized to generate high-value chemicals during photocatalytic hydrogen production, then photocatalytic water splitting is more meaningful in consideration of green chemistry. GONaOH was obtained after hydrothermal treatment of graphene oxide (GO) using 10 mol L−1 NaOH. The average hydrogen production rate could reach 7.36 mmol h−1 over 0.50 g L−1 GONaOH photocatalyst for a reaction of 12 h. And the sacrificial agent isopropanol could undergo selective oxidative C–C coupling to generate pinacol. The isopropanol conversion rate was 77.95%, and the pinacol selectivity was 62.32%. Also, the GONaOH photocatalytic selective oxidative C–C coupling mechanism of isopropanol was further studied. The ṖOH concentration on the photocatalyst surface was verified as a key factor influencing pinacol selectivity. Under the effect of GONaOH photocatalyst, ṖOH radicals were used for the oxidative dehydrogenation of isopropanol to generate 2-hydroxyisopropyl radicals, and pinacol was generated through C–C coupling. Meanwhile, acetone byproducts could further undergo hydrogenation–dehydrogenation coupling reaction with isopropanol to finally generate pinacol. [ABSTRACT FROM AUTHOR]

Abstract: Photocatalyst activity is influenced by many factors, such as adsorption of by‐products, runoff of surface hydroxyl groups and carriers. In this study, a simple and efficient photocatalyst regeneration method was developed. Results indicated that NaTaO3 photocatalyst lost its photoactivity after three cycles of reaction that involves coupling of isopropanol and hydrogenation coupling of acetone reaction system. Runoff of Na on the surface was the main reason for the deactivation of NaTaO3 photocatalyst. After hydrothermal treatment of the deactivated NaTaO3 with 10 m NaOH at 180°C for 12 h, its photocatalytic activity was restored to the original level. The photocatalytic activity remained stable even after 10 cycles. [ABSTRACT FROM AUTHOR]

2,3-Butanediol (2,3-BD) was synthesized through TiO2-photocatalytic CC coupling of bioethanol synchronously with the liberation of an energy H2 molecule in an anaerobic atmosphere. It was found that the selectivity of 2,3-BD is controlled by the amount of .OH. The less the .OH, the higher the 2,3-BD selectivity. Furthermore, it was revealed that the amount of .OH increases with the increasing of the surface OH groups on TiO2 photocatalyst. The introduction of water is in favor of the CC coupling pathway. This can be attributed to the stronger interaction between water and TiO2, which is beneficial to recovering the OH groups and promoting the desorption of .CH(OH)CH3 intermediates, thus suppressing the thermodynamically favorable overoxidation of .CH(OH)CH3 into acetaldehyde and promoting the CC coupling into 2,3-BD. Based on the findings, the 2,3-BD selectivity was greatly enhanced from approximately 2.6 % to approximately 65 % over Degussa P25-TiO2 photocatalyst through fluorine substitution of surface OH groups. [ABSTRACT FROM AUTHOR]

Carbon nanodots without any modification can drive photocatalytic hydrogen evolution. More importantly, we found that Z-scheme is an effective strategy to improve the photocatalytic performance of carbon nanodots. The photocatalytic H2-evolution rates improve from 4.65 μmol g−1 h−1 to 1330 μmol g−1 h−1 under xenon lamp irradiation. [ABSTRACT FROM AUTHOR]

Two new metal-organic frameworks (MOFs) having the formula [Ln 2 (H 2 O) 3 (L) 3 ·3H 2 O] n (Ln = Sm for MOF-Sm and Tb for MOF-Tb) have been synthesized solvothermally by reacting LnCl 3 ·6H 2 O with 5-(1 H -1,2,4-triazol-1-yl)-1,3-benzenedicarboxylic acid (H 2 L) and characterized. Single crystal X-ray analyses for MOF-Sm and MOF-Tb revealed that both MOFs are isostructural and display a (6,8)-connected 3D structure with a point symbol of (3 5 ·4 4 ·6 6 )(3 5 ·4 6 ·5 17 ). The natures of weak interactions existing in both MOFs have been assessed using Hirshfeld surface analyses and fingerprint plots. The utility of MOF-Sm as a photocatalyst for the safe photodegradation of the model aromatic dye methyl violet (MV) is also checked. The photocatalysis results showed that MOF-Sm offers reasonable photocatalytic degradation of this dye. The plausible photocatalytic mechanism of MOF-Sm aided photocatalysis has been explained with the help of band gap calculations using density of states (DOS) and partial DOS plots., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this work, a series of novel SnO 2 /ZnO nanocomposites with different morphologies were fabricated via a facile hydrothermal technique followed by calcination in air. The morphological, structural and photocatalytic properties of the SnO 2 /ZnO nanocomposites were studied using different methods. The results showed that the synthesized nanocomposites possessed crystal phases of wurtzite hexagonal phase ZnO and tetragonal rutile phase SnO 2 . In addition, the morphologies of SnO 2 /ZnO nanocomposites strongly depended on the molar ratios of Sn and Zn. Compared with ZnO and SnO 2 , the SnO 2 /ZnO nanocomposites exhibited considerably higher degradation efficiency for the photodegradation of methylene blue and quinolone antibiotics under mercury lamp irradiation. The SZ-2 nanospheres exhibited the highest degradation efficiency of 95.81%, which was about 2.63 times higher than that of ZnO nanoparticles. Moreover, the trapping experiments confirmed that ˙OH played the dominant role in MB degradation. Finally, the charge carriers potential transfer pathway and photocatalytic degradation mechanism were put forward. This study provides an economical way to prepare hybrid nanocomposites with controlled morphology for practical applications in the photocatalytic degradation of organic dyes and residual antibiotics., (© 2019 American Society for Photobiology.)

Photocatalyst activity is influenced by many factors, such as adsorption of by-products, runoff of surface hydroxyl groups and carriers. In this study, a simple and efficient photocatalyst regeneration method was developed. Results indicated that NaTaO 3 photocatalyst lost its photoactivity after three cycles of reaction that involves coupling of isopropanol and hydrogenation coupling of acetone reaction system. Runoff of Na on the surface was the main reason for the deactivation of NaTaO 3 photocatalyst. After hydrothermal treatment of the deactivated NaTaO 3 with 10 m NaOH at 180°C for 12 h, its photocatalytic activity was restored to the original level. The photocatalytic activity remained stable even after 10 cycles., (© 2017 The American Society of Photobiology.)