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• Surfactant-assisted synthesis is a promising method for photocatalyst synthesis. • Surfactant would efficiently enhance the photocatalytic activity of photocatalysts. • Surfactant can regulate the morphology and structure of photocatalysts. • Influencing factors and recent advances are highlighted. The presence of large amounts of contaminants in the environment would result in ecological and health hazards. The photocatalytic technologies have been developed to use sunlight to remove contaminants in recent years. Researchers are primarily focused on developing high-performance photocatalysts. This review discusses the effects of surfactant on the structural morphology, physicochemical properties and contaminant removal performance of photocatalysts. The mechanism and synthesis method of surfactant-assisted photocatalysts are reviewed. Meanwhile, the effects of surfactant type, surfactant concentration, solution pH, synthesis method and calcination temperature on the photocatalysts are also discussed in detail. In addition, we summarized the recent advances and the application of surfactant-assisted photocatalysts in the environmental remediation. Finally, the future researches on surfactant-assisted photocatalysts are also proposed. This review provides new insights into the use of surfactants to prepare photocatalysts with well-defined shape and excellent performance to enhance photocatalytic efficiency for removing pollutants. [ABSTRACT FROM AUTHOR]

A high-performance piezoelectric photocatalyst (V-BiOIO 3 /FTCN) was constructed to improve removal efficiency of tetracycline hydrochloride (TCH). The role of V-BiOIO 3 in the composite was to introduce piezoelectric effect and construct S-scheme heterojunction photocatalyst with fish scale tubular carbon nitride (FTCN). The morphology, structure, chemical composition and optoelectronic characteristics of the as-prepared photocatalysts were studied by SEM, TEM, XRD, XPS and UV-Vis DRS. Combined with UV-Vis DRS, XPS valence band, Mott-schottky curve and theoretical calculations, the mechanism of TCH degradation was deeply analyzed. A series of degradation experiments showed that the V-BiOIO 3 /FTCN could effectively degrade TCH, and the removal efficiency was further improved under the action of ultrasound. Importantly, the further immobilized V-BiOIO 3 /FTCN/MS could float on the water surface to degrade TCH without additional stirring, which facilitated the recovery of photocatalysts and showed excellent practical application value. This work provided a reference for the design and immobilization of carbon nitride-based piezoelectric photocatalysts. [Display omitted] • Novel piezoelectric photocatalyst V-BiOIO 3 /FTCN was successfully prepared. • The transfer style of e and h+ between V-BiOIO 3 and FTCN belonged to S-scheme. • The mechanism was explored through experiments and theoretical calculations. • The floatable V-BiOIO 3 /FTCN/MS had good practical application prospects. [ABSTRACT FROM AUTHOR]

2D graphitic carbon nitride (GCN) nanosheets have attracted tremendous attention in photocatalysis due to their many intriguing properties. However, the photocatalytic performance of GCN nanosheets is still restricted by the limited active sites and the serious aggregation during the photocatalytic process. Herein, a simple approach to produce holey GCN (HGCN) nanosheets with abundant in-plane holes by thermally treating bulk GCN (BGCN) under an NH3 atmosphere is reported. These formed in-plane holes not only endow GCN nanosheets with more exposed active edges and cross-plane diffusion channels that greatly speed up mass and photogenerated charge transfer, but also provide numerous boundaries and thus decrease the aggregation. Compared to BGCN, the resultant HGCN has a much higher specific surface area of 196 m2 g−1, together with an enlarged bandgap of 2.95 eV. In addition, the HGCN is demonstrated to be self-modified with carbon vacancies that make HGCN show much broader light absorption extending to the near-infrared region, a higher donor density, and remarkably longer lifetime of charge carriers. As such, HGCN has a much higher photocatalytic hydrogen production rate of nearly 20 times the rate of BGCN. [ABSTRACT FROM AUTHOR]

Due to the low efficiency of single-component nano materials, there are more and more studies on high-efficiency composites. As zero dimensional (0D) non-metallic semiconductor material, the emergence of graphene quantum dots (GQDs) overcomes the shortcomings of traditional photocatalysts (rapid rate of electron-hole recombination and narrow range of optical response). Their uniqueness is that they can combine the advantages of quantum dots (rich functional groups at edge) and sp2 carbon materials (large specific surface area). The inherent inert carbon stabilizes chemical and physical properties, and brings new breakthroughs to the development of benchmark photocatalysts. The photocatalytic efficiency of GQDs composite with semiconductor materials (SCs) can be improved by the following three points: (1) accelerating charge transfer, (2) extending light absorption range, (3) increasing active sites. The methods of preparation (bottom-up and top-down), types of heterojunctions, mechanisms of photocatalysis, and applications of GQDs/SCs (wastewater treatment, energy storage, gas sensing, UV detection, antibiosis and biomedicine) are comprehensively discussed. And it is hoped that this review can provide some guidance for the future research on of GQDs/SCs on photocatalysis. [Display omitted] • The synthesis methods of GQDs/SCs are summarized. • The roles of GQDs in improving the photocatalytic efficiency of SCs are emphasized. • Photoelectric properties and biocompatibility make GQDs/SCs are used in environment, biomedicine, etc. • The opportunities and challenges of GQDs/SCs are described. [ABSTRACT FROM AUTHOR]

On page 6885, Z‐H. Huang, Q.‐H.Yang, and co‐workers demonstrate an efficient thermal etching process for the synthesis of holey graphitic carbon nanosheets, via etching of bulk graphitic carbon nitride under an ammonia atmosphere. These nanosheets exhibit significantly improved photocatalytic activity towards hydrogen evolution reactions under visible light conditions, up to 20 times that of the bulk material. [ABSTRACT FROM AUTHOR]

Morphology adjustment is a feasible method to change the physicochemical properties of photocatalysts. The issue that excessively thick tube wall of tubular g-C 3 N 4 is not conducive to the electron migration from inside to the surface thus inhibiting the separation of photogenerated carriers has always been ignored. Potassium ions were used to regulate the structure of the tubular supramolecular precursor by breaking hydrogen bonds, thereby promoting the synthesis of delaminated laminar tubular g-C 3 N 4 (K-CN), which not only shortened the transfer distance of photogenerated electrons but also provided abundant reaction active sites. Experiments and DFT calculations were combined to reveal the details of the physicochemical properties of K-CN. The photocatalytic capacity of K-CN for tetracycline hydrochloride (TCH) degradation and H 2 O 2 generation were 83% and 133 μM, respectively. This work not only synthesized a novel delaminated tubular g-C 3 N 4 but also provided a strategy and inspiration for structure and performance optimization for tubular g-C 3 N 4. [Display omitted] • Supramolecular self-assembly produced tubular g-C 3 N 4 precursors. • Potassium ions was influenced on the supramolecular self-assembly. • Destruction of the hydrogen bond induced delamination of tubular g-C 3 N 4. • Experiment and DFT calculation were combined to reveal the properties of K-CN. • Delamination promoted K-CN showed strong photocatalytic activity. [ABSTRACT FROM AUTHOR]

Pharmaceuticals and personal care products (PPCPs) are a large class of emerging contaminants. Here, we develop a 2D/2D Mo 2 C/g-C 3 N 4 Van der Waals (VDW) heterojunction photocatalyst for typical PPCPs degradation. The 2D Mo 2 C shows unique electronic transport properties and allows the integration with other 2D materials for fabricating intriguing 2D interface. The Mo 2 C strongly coordinates with g-C 3 N 4 to endow the ordered in-plane electron migration in g-C 3 N 4 nanosheets and the VDW forces induce the electrons transfer within interlayers, building an internal electric field and stimulating the photogenerated charge kinetics. In addition, Mo 2 C can ameliorate the light absorption capacity and trap electrons to elongate the lifetimes of charge carriers. This synergy between VDW heterojunction and 2D structure engineering contributes to the superior photocatalytic activity for tetracycline degradation. Advanced characterizations, charge density based on density function theory calculations and the absence of charge transfer between layers confirm the VDW interactions between the individual components. This work provides a highly efficient and green strategy for typical PPCPs removal, and sheds lights on the construction of 2D/2D VDW heterojunction photocatalysts. [Display omitted] • The g-C 3 N 4 and Mo 2 C based 2D/2D novel Van der Waals heterostructure is reported. • Advanced characterizations combined with DFT calculations confirm the strong electronic coupling. • The Mo 2 C strongly coordinates with CN to endow CN ordered in-plane electron migration. • The internal electric field is established and it synergistically enhances the photocatalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sulfur doped hollow tubular g-C 3 N 4 was prepared through molecular self-assembly. • A noval 2D/1D BOC/SCN hierarchical heterostructure was constructed. • BOC/SCN composites exhibited outstanding photocatalytic activity and stability for TCH degradation. • A possible Z-scheme charge transfer pathway and degradation mechanism were proposed. The construction of heterojunction photocatalysts was considered to be an effective strategy to tackle refractory pollutants. However, most of the reported composites lacked precise control of their morphology, resulting in unsatisfactory catalytic activity. In this work, we successfully fabricated sulfur doped g-C 3 N 4 hollow tubes (SCN) via molecular self-assembly, and then grew the Bi 2 O 2 CO 3 nanoflakes (BOC) in situ parallel on the surface of SCN to construct 2D/1D interfacial phase. Within 30 min visible light irradiation, the robust BOC/SCN-3 heterostructure showed considerable improvement for tetracycline degradation (82.6%) compared with individual components. This enhanced photocatalytic performance derived from the synergistic effect of S doping and heterojunction interface contact. The tubular structure formed by S doping not only narrowed the bandgap and thus boosting the visible light harvesting of CN, but also promoted electrons to travel along the 1D longitudinal and radial directions. In addition, the built-in electric field between BOC and SCN effectively achieved the spatial separation of electron-hole pairs. Mechanism analysis revealed that the h+ and •O 2 − radicals played the dominating contribution in the photocatalytic process, and a possible Z-scheme mechanism was proposed. It was expected that such design route could provide a new perspective on hierarchical heterostructure for pollutant removal. [ABSTRACT FROM AUTHOR]

• The photocatalytic mechanism of Zr-MOFs with different photo active ligands. • Post synthesis modification of Zr-MOF based photocatalysts. • The heterogeneous photocatalytic systems based on Zr-MOFs. • Application, mechanism, and prospect of Zr-MOF based photocatalysts. Recently, Zirconium (Zr) based metal organic frameworks (Zr-MOFs) materials have gathered increasing interest in the field of photocatalysis. Zr-MOFs not only have the large surface area, orderly porous structure, and tunable organic bridging linker/metal clusters as other MOFs, but also possess higher thermal stability and excellent water-tolerant than most of other MOFs. In this review, the Zr-MOFs with excellent photocatalytic properties reported in recent years are reviewed. Moreover, the strategies of improving the photocatalytic activity of Zr-MOFs and their applications in water splitting for hydrogen production, carbon dioxide reduction, removal of organic pollutants and Cr(Ⅵ) reduction are discussed, in addition, the mechanisms of these processes are also described in detail. Finally, the future developments and challenges of Zr-MOFs photocatalyst are also prospected. [ABSTRACT FROM AUTHOR]

• AgI/ZSH hollow cubes are obtained by the self-templating and deposition-precipitation method at room temperature. • AgI/ZSH for photocatalytic degradation of oxytetracycline hydrochloride under visible light. • AgI/ZSH has a better degradation effect in the pH greater than 5. • Hollow structure forms a high surface area and fast charge separation. ZnSn(OH) 6 has been widely used in the photocatalytic field due to unique face-centered-cube structure and the full hydroxyl groups on the surface, but is still unsatisfied because of its wide band gap. Herein, a novel AgI/ZnSn(OH) 6 hollow cube nanocomposite (AgI/ZSH) with superior visible-light-driven photocatalytic activity was prepared by a simple and room temperature synthesis method for overcoming these defects. The experimental and density functional theory (DFT) theoretical calculations illustrated that AgI nanoparticles loaded ZSH hollow cube can significantly enhance light absorption and accelerate the transfer of charges because of the special hollow structure of ZSH as well as suitable band gap between AgI and ZSH. The AgI/ZSH photocatalyst presented superior degradation effect for oxytetracycline hydrochloride (OTC). The degradation rate of AgI/ZSH increased by 26.31% and 93.36% compared with AgI and ZnSn(OH) 6 , respectively. The influences of initial OTC concentrations, pH, coexistence ions, and water sources were discussed in detail. Results showed that the photocatalyst is adapted to different environments. The excellent photo-stability of the product was confirmed by the basically unchanged degradation rate after four cycles. ESR and radical trapping experiments were employed to certify superoxide radical (O 2 −) and holes (h+) as the main active species. The degradation products and possible pathways of OTC were obtained through LC-MS/MS and the possible degradation mechanism was analyzed. This discovery provides an excellent approach for the synthesis of high-efficiency composite materials with non-spherical hollow structures under room temperature conditions for the degradation of antibiotics. [ABSTRACT FROM AUTHOR]

[Display omitted] • The application of ZIF/ZIF derivative based composite photocatalysts was reviewed. • Special attention has been paid to the catalytic mechanism. • The synergistic effects between the components are discussed. • The challenges and opportunities in this interesting field are presented. To solve the problem of the global energy shortage and the widespread pollution of the environment, semiconductor photocatalytic technology has been widely studied. Zeolitic imidazolate frameworks, a sub-family of metal-organic frameworks, have emerged as potential candidates for photocatalysis due to their intrinsic porous characteristics, abundant functionalities, rapid electron transfer ability, and exceptional thermal and chemical stabilities. Besides, a thermal treatment of zeolitic imidazolate frameworks can result to functional materials that have the similar structure characteristic, but superior light sensitivity and charge transfer properties. Moreover, the photocatalytic activity of zaeolitic imidazolate frameworks and their derivatives can be largely improved by combining photoactive semiconductors/ molecules which serve as light harvesting centers/electronic mediators. This paper presents a first review of the application of zaeolitic imidazolate frameworks and their derivatives -based materials for visible-light-induced photocatalytic hydrogen evolution and pollutants treatment. The representative studies are carefully summarized and discussed. Special emphasis is given to the synergistic effects between the components in the composite catalyst for enhanced photocatalysis. At the end of this review, the current achievements together with major challenges in the field are discussed and the next possible development directions are proposed. [ABSTRACT FROM AUTHOR]

• Ultrathin, porous and vacancy-rich CoAl-LDHs nanosheets were prepared by exfoliation strategy. • 2D/2D CoAl-LDHs/Ti 3 C 2 T x hybrids were synthesized via electrostatic assembly process. • Electronic and optical properties were calculated based on density functional theory. • CoAl-LDHs/Ti 3 C 2 T x hybrids exhibited high visible-light photodegradation of antibiotic. • Synergistic effect between CoAl-LDHs and Ti 3 C 2 T x endowed the excellent photocatalytic activity. The layered double hydroxides (LDHs) are potential non-noble metal photocatalysts. Unfortunately, the intrinsic activity of bulk LDHs is relatively low, which limits their use. Herein, the ultrathin, porous and vacancy-rich CoAl-LDHs nanosheets were prepared by exfoliation strategy. Then, they were assembled with the early transition-metal carbides nanosheets (MXenes, Ti 3 C 2 T x) to afford a hybrid 2D/2D CoAl-LDHs/Ti 3 C 2 T x photocatalyst via electrostatic assembly process. The experiments indicated that the CoAl-LDHs/Ti 3 C 2 T x hybrids performed an excellent visible-light photocatalytic activity for tetracycline hydrochloride (96.67 %) degradation. Diversified characterization techniques (SEM, TEM, AFM, N 2 adsorption-desorption analysis, XRD, FTIR, UV–vis DRS, photoelectrochemical test) and density functional theory calculations (electronic and optical properties) have indicated that such excellent photocatalytic activity was ascribed to the synergy and the Schottky heterojunction formation between CoAl-LDHs nanosheets and Ti 3 C 2 T x nanosheets, which possessed markedly visible-light absorption, high specific surface area, rapid electrons transfer and depressed electron-hole pairs recombination. [ABSTRACT FROM AUTHOR]

• Metal sulfide/MOF-based visible-light-driven hydrogen evolution was reviewed. • Special attention has been paid to the catalytic mechanism. • The synergistic effects between metal sulfide and MOF shells are discussed. • The future development prospects of this technology are proposed. Solar energy driven photocatalytic hydrogen (H 2) production from photocatalytic water splitting is considered as one of the most promising technologies to solve the energy and environmental crises. In the recent years, metal sulfide/MOF-based composites have attracted increasing attention in visible-light-driven photocatalytic H 2 production owing to their multiple advantages, such as high photochemical stability, broad light absorption and effective charge separation efficiency. Even though this field is currently in its infancy, the promising results obtained suggest that these composite photocatalysts have high potential for practical applications. In this review, we provide an overview of the progress in the design and synthesis of various metal sulfide/MOF-based nanocomposites for applications in photocatalytic H 2 production. Special consideration has been given to the synergistic effects between metal sulfide and MOF (or MOF derivative) that result in an enhanced photocatalysis. We also present some important examples showing that non-noble metal cocatalysts could serve as efficient cocatalysts for promoting photocatalytic H 2 production. Finally, the remaining issues in this field are discussed and future directions and challenges are outlined. [ABSTRACT FROM AUTHOR]