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Herein, well‐crystallized ZnTiO3 particles are first prepared by hydrothermal method. A series of S‐scheme heterojunction photocatalysts of ZnTiO3/g‐C3N4 (referred to as ZTO/CN) with different mass ratios are synthesized by successfully doping ZnTiO3 in g‐C3N4 precursors and loading ZnTiO3 onto g‐C3N4 nanosheets by calcination. It is clearly found that the ZnTiO3 particles are successfully loaded on g‐C3N4 nanosheets by the X‐ray diffractometer, energy‐dispersive X‐ray spectra, and high‐resolution transmission electron microscopy images. Moreover, the specific surface area of 3.0% ZTO/CN is higher than that of pure g‐C3N4. Using triethanolamine as the hole sacrificial agent, the highest CO and H2 yields are achieved in the 3.0% ZTO/CN composite catalyst under the xenon lamp irradiation for 1 h. The generation rates of CO and H2 reach 15.19 and 5.77 μmol g−1 h−1, respectively, which are 2.9 and 4.1 times higher than that of pure g‐C3N4. The CO and H2 yields of the ZTO/CN composite catalyst show a trend of increasing and then decreasing with the increasing of ZnTiO3 content, which is due to the fact that excess ZnTiO3 can lead to a reduction of the effective heterojunction interface between ZnTiO3 and g‐C3N4, decreasing the transfer and separation efficiency of photogenerated electrons and holes and thus reducing the photocatalytic activity. [ABSTRACT FROM AUTHOR]

• Sm3+/Tm3+ co-doped BiVO 4 micro-squares were synthesized. • Sm3+/Tm3+ co-doping reduced the recombination of photogenerated electrons and holes. • Sm3+/Tm3+ co-doping provides additional light absorption. • Sm3+/Tm3+ co-doping brings about the remarkable photocatalytic activity for CO and CH 4 production. Solar-driven photocatalytic reduction of CO 2 to fuels and chemicals with added value has attracted intense attention. Here, the Sm3+/Tm3+ co-doped BiVO 4 micro-squares were synthesized by hydrothermal method. The prepared samples were characterized by some physicochemical methods such as XRD, FT-IR, SEM, TEM, XPS, UV–Vis DRS, EPR, N 2 physisorption -desorption and electrochemical analysis. The CO 2 reduction ability of the catalysts with different rare earth content was evaluated under xenon lamp irradiation. We found that BiVO 4 photocatalyst co-doped with 10%Sm and 10%Tm (mole percent) showed the remarkable photocatalytic activity for CO and CH 4 production. The CO production rate over 10%Sm/10%Tm/BiVO 4 was around 5 times higher than that of pure BiVO 4 and single rare earth doped BiVO 4. The enhanced activity can be attributed that the Sm3+/Tm3+ co-doping reduced the recombination rate of photogenerated electrons and holes, provides additional light absorption and more active sites for CO 2 reduction. Sm3+/Tm3+ co-doping can regulate the energy band structure and carrier separation of BiVO 4 which effectively boosts the CO photocatalytic reduction for CO and CH 4 production. [Display omitted] [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]

Photocatalysts based on Z-scheme heterostructure have been extensively investigated for CO 2 reduction and hydrogen production, which solve the problem of high electron-hole pair complexation and low reduction and oxidation capacity in photocatalysts. Here, two-dimensional CuTiO 3 /g-C 3 N 4 (CTO/CN) photocatalysts with directly Z-scheme heterostructure are prepared by effective manipulation of different components of CuTiO 3 (CTO) nanoparticles on 2D (two-dimension) porous g-C 3 N 4 (CN) nanosheets via in-situ growing strategy. Benefited from the special electronic structure, it demonstrates that the 4.0 % CTO/CN sample has an excellent photocatalytic activity for the reduction of CO 2 to H 2 (at a speed of 19.56 μmol g−1 h−1) and CO (at a speed of 19.93 μmol g−1 h−1), which are upper than those of pure g-C 3 N 4 by 43.5 and 17.1 times, respectively. Furthermore, the 4.0 % CTO/CN sample exhibits utstanding performance in electrocatalytic hydrogen production. This synthetic strategy is useful for constructing a 2D Z-scheme heterostructure for applications in energy-related areas. Schematic diagram of electrochemical hydrogen precipitation and carbon dioxide reduction of CuTiO 3 /CN heterojunction composites prepared by in situ growth method. [Display omitted] • A series of CuTiO 3 /g-C 3 N 4 nanosheets were prepared by applying in situ growth method. • CuTiO 3 /g-C 3 N 4 exhibits excellent performance for CO 2 reduction under visible light irradiation. • The 4.0 % CTO/CN had excellent electrochemical stability performance under neutral conditions. [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]

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]

[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]

• 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]

• Advances in photocatalytic inactivation ability with g-C 3 N 4 -based nanomaterials. • Elucidates photocatalytic disinfection efficiency and possible reaction mechanism. • The latest design considerations of g-C 3 N 4 -based photocatalysts are described. Microbial contamination in wastewater systems is a global problem and has attracted more and more attention. Therefore, a high-performance and environmentally friendly inactivation method is in great demand. Graphitic carbon nitride (g-C 3 N 4) exhibits lots of prominent properties such as appealing physicochemical stability, unique two-dimensional structure and tunable electronic structure. Unsatisfactorily, the pristine g-C 3 N 4 also faces the shortcomings arising from the limited visible light response and few active sites. Hence, a comprehensive review ("can we go further?") about modified g-C 3 N 4 photocatalysts for solar photocatalytic disinfection is necessary, which provides some inspiration for further optimization of the g-C 3 N 4 -based photocatalytic disinfection system. Meanwhile, the performance of g-C 3 N 4 -based photocatalysts for photocatalytic bacterial disinfection and the involved mechanisms are reviewed. In addition, the current prospects and possible challenges are pointed out. This review aims to summarize recent studies of g-C 3 N 4 -based photocatalysts in environmental disinfection and open a bright window to this booming research theme. [ABSTRACT FROM AUTHOR]