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[Display omitted] • Self-regulating S-scheme heterojunction of titanate nanotubes/Bi 2 WO 6 was constructed. • Synergistic effect between hexavalent chromium and tetracycline, with synchronous self-exchange of trivalent chromium. • Trivalent chromium incorporation into titanate nanotubes' interlayer, optimizing the heterojunction. • The degradation pathways of tetracycline were predicted through the Fukui index. The limitation of conventional photocatalysts in simultaneously removing Tetracycline (TC), hexavalent chromium (Cr (VI)) and trivalent chromium (Cr (III)) were addressed in mixed pollution treatment. The S-scheme heterojunction of titanate nanotubes/Bi 2 WO 6 (TNTs/BWO) was successfully constructed to achieve efficient removal of TC, Cr (VI), and Cr (III). The theoretical calculations (DFT) demonstrated that TNTs' ion exchange properties led to the partial replacement of interlayer Na+ by Cr (III), optimizing the S-scheme heterojunction during the photocatalytic reaction. Experimental results revealed that the coexistence of TC, Cr (VI), and Cr (III) had a mutual promotion effect, as evidenced by the apparent rate constant of Cr (VI) reaching 0.7 min−1, which was 87.5 times higher than that of the single pollutant system, while maintaining a high apparent rate constant for TC. The likely intermediate products, degradation pathways, and photocatalytic mechanism were also elucidated using DFT molecular orbitals and Fukui index analysis. This work provides new insights and strategies for simultaneously removing pollutants and contributes to wastewater purification. [ABSTRACT FROM AUTHOR]

Abstract In this study, CNCs-TiO 2 heterojunctions were synthesized successfully via a two-step method. The obtained materials were systematically characterized by a series of technologies including XRD, TEM, HRTEM, FT-IR, XPS, UV-DRS, PL and EIS. Moreover, the photocatalytic activity of CNCs-TiO 2 was evaluated by the photodegradation of crystal violet (CV) under UV and visible light irradiation. The results of characterization demonstrated that the CNCs-TiO 2 heterojunctions were formed. For composite CNCs-TiO 2 , the anatase TiO 2 was uniformly dispersed on the surface of CNCs with graphite structures via a new chemical bond, Ti O C and the growth of crystalline grains was inhibited. The photo-absorbing range of TiO 2 was extended to the visible light region after coupling with CNCs leading to the enhancement of light-harvesting ability. In addition, compared with pure TiO 2 particles, the recombination of photoinduced electrons and holes was restrained. The photodegradation experiment indicated that the CNCs-TiO 2 exhibited enhanced photocatalytic activity in contrast with TiO 2 under UV and visible light irradiation, which was the result of the combined action of improved adsorption capability, enhanced light harvesting performance and efficient charge separation and transfer. The degradation of CV in the photocatalytic system followed the pseudo-first-order kinetics model. Lastly, the main mechanism for the enhanced photocatalytic activity of CNCs-TiO 2 was significantly put forwarded. [ABSTRACT FROM AUTHOR]

Construction of Z-scheme heterostructure is an effective strategy to enhance the charge carriers' separation. However, successfully achieving this on the defect heterojunction to improve the photocatalytic activity remains challenging. This work successfully obtained sulfur vacancy in the ZnIn 2 S 4 /BiOBr (SZIS/BOB) heterojunction composites with S–O covalent bonding using a hydrothermal method. As a result, they exhibited superior photocatalytic and stability performance. The optimized SZIS/BOB-10 exhibited excellent rhodamine B degradation (95.2%) and chromium (VI) reduction (97.8%) within 100 min under visible light. The enhanced composites with S-vacancies, S–O bond, and internal electric field induced the Z-scheme charge transfer mechanism. We had verified this mechanism based on the surface photovoltage spectra, electron spin response spectra, and density functional theory calculations. This work not only provides valuable insights into designing photocatalysts with a direct Z scheme heterostructure but also delineates a promising strategy for developing efficient photocatalysts to degrade organic pollutants. Schematic illustration of the possible photoelectron generation and transport routes in the SZIS/BOB heterostructure. Also, the photocatalytic reaction mechanism for RhB degradation and Cr(VI) reduction under visible light irradiation. [Display omitted] • Constructing surface defect ZnIn 2 S 4 /BiOBr heterojunction. • The S–O covalent bond was found in the ZnIn 2 S 4 /BiOBr heterojunction interface. • The S–O bond boosting interfacial charge transfer in ZnIn 2 S 4 /BiOBr heterojunction. • ZnIn 2 S 4 /BiOBr exhibited outstanding photocatalytic performance under visible light. [ABSTRACT FROM AUTHOR]

• A novel membrane was constructed for the first time. • Efficient and simultaneous water evaporation and decontamination were achieved. • Synergic actions towards the high performances were identified. • Insights into the in-situ photodriven obtaining of clean water were approached. Construction of semiconductor-based membranes accommodates new routes for photothermal conversion and in-situ decomposing of pollutants in solar light-driven evaporation. In this work, a novel photocatalyst composed of MoO 3- x , BiOCl, and carbon nanotubes was surficial deposited on cellulose acetate membrane. High capillary pressure (∼600 kPa) guaranteed an effective capillary rise of water from hydrophilic membrane matrix. The water was extruded into ultra-fine droplets with a saturation vapor pressure as high as ∼1.75 × 105 Pa and a heat flux as much as ∼2.11 × 10−3 W mm−2. Moreover, the top-surficial film can harvest sufficient solar photons to generate charge carries, and the surface temperature of membrane can quickly increase to higher than 50 °C by thermalization through carriers relaxation, transference, and recombination on specific sites. Simultaneously, pollutants in water are efficiently decomposed by effectively separated charge carriers on designed spots. Synergistically, a steam generation rate of ∼7.75 kg m−2 h−1 was acquired and an almost complete removal of RhB and toluene was achieved. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalytic technology is an effective strategy to cope with the current environmental issues. Therefore, the development of low-cost and environment-friendly catalysts with high efficacy has become a research focus and emphasis. Herein, novel Z-scheme In 2 S 3 /Bi 2 WO 6 core-shell structure composites were controllably prepared by template and hydrothermal route. Highly improved photocatalytic degradation of tetracycline hydrochloride (TCH) over In 2 S 3 /Bi 2 WO 6 core-shell composites was observed under visible-light (VL) irradiation (∼96.0%), which was 2.4 and 2.1 folds higher than that of In 2 S 3 and Bi 2 WO 6 , respectively. The excellent oxygen activation and catalytic performance was ascribed to the synergistic effects of built-in electric field to ensure easy charge exchange at the interface of In 2 S 3 and Bi 2 WO 6 , Z-scheme charge transfer path and the extended range of VL absorption. Superoxide radical (·O- 2) and hydroxyl (·OH) radicals were verified to be involved in the photocatalytic reaction by the active species capture experiment and the electron spin response (ESR) detection. The recycling experiments demonstrate the excellent stability and reusability of the In 2 S 3 /Bi 2 WO 6. In addition, in accordance with the experimental results, the highly efficient Z-scheme photocatalytic mechanism and degradation paths were proposed. This work provided a new way for preparation of Z-scheme core-shell composites which had broad applications prospect in environmental remediation. The possible photocatalytic mechanism for TCH degradation in the Z-scheme In 2 S 3 /Bi 2 WO 6 system. [Display omitted] • Novel In 2 S 3 /Bi 2 WO 6 core-shell heterojunctions were acquired. • The In 2 S 3 /Bi 2 WO 6 heterojunctions exhibits superior photocatalytic activity. • Boosting photocatalytic performance is due to the synergistic effects. • · O- 2 and · OH radicals played a decisive role in the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Construction of diverse dimensional heterojunctions succeed via simple assembly method. • Heterojunctions exhibited superiorities over individuals in TC-HCl removal with the 2D/2D to be the best. • An S-scheme was proposed and enhanced performances of heterojunctions were explained. • Vital importance of interfacial intimacy in heterojunctions was revealed. As a structural parameter, dimensionality is a key factor but was usually ignored in the design of novel heterojunction architectures in achieving their photocatalytic performances. Hence in this work, we obtained one-dimensional titanate nanotubes (TNTs), two-dimensional titanate nanoflakes (TNF) and three-dimensional titanate nanospheres (TNS) with facile treatments of TiO 2 by NaOH, and combined them with two-dimensional sulfur-doped g-C 3 N 4 nanoflakes (SCN), respectively, through magnetic and ultrasonic mixing in isopropanol. Their performances in photodegradation of tetracycline hydrochloride (TC-HCl) under simulated solar light irradiation exhibit significant superiorities of the composites over their individuals, while the photodegradation rates obtained on composites indicate a vital importance of their interfacial intimacy in heterojunctions. The photoactivity of TNF/SCN with a suitable face-face contact represents a rate constant as high as 0.1642 min−1, which is 1.58 and 2.65 times of what on TNS/SCN (0.1036 min−1) and TNTs/SCN (0.0619 min−1), respectively. Careful characterization and theoretical calculation indicated dense junction between different titanates and SCN via van der Waals integration. In these dense heterojunctions, an internal electronic field of about 0.75 V can automatically be formed between titanates and SCN during the assimilation of their Femi level by electronic coupling, to realize migration and separation of photogenerated carriers through an S-scheme. Moreover, the interfacial intimacy benefited from suitable dimensionality of titanates can promote the efficiency of S-scheme to acquire a prolonged lifetime of •OH and •O 2 –, and intraparticle transfer of TC-HCl towards their degradation. This work provides new insights into the rational design of heterostructures based on dimensional modulation on the interfacial affinity for accelerating the transfer of interfacial charge and the intraparticle transfer of contaminants. [ABSTRACT FROM AUTHOR]

• Successful fabrication of unique 2D/2D hetero-architecture via in-situ assembly method. • Synergistic effects of different roles of sulfur doping in the enhanced photocatalytic performances of SCN and TNS/SCN. • Distinct difference in Femi levels via the modulation of sulfur doping was evidenced by DFT calculations. • Distinct difference in Femi levels enhanced the electronic coupling and accelerated the interfacial charge transport. • Mechanisms toward the TC-HCl degradation and S-scheme interfacial charge transports were proposed. In this study, novel titanate nanosheets/g-C 3 N 4 (TNS/CN) and titanate nanosheets/sulfur-doped g-C 3 N 4 (TNS/SCN) heterojunctions were successfully fabricated by the in-situ assembly for the efficient removal of tetracycline hydrochloride (TC-HCl). TNS/SCN achieved 1.87, 7.89 and 3.27 times increases in photodegradation performance compared to TNS/CN, TNS and SCN, respectively, due to the collaboration of the unique 2D/2D hetero-architecture, synergistic effects of different roles of sulfur doping in SCN and TNS/SCN, and step-scheme interfacial charge transport. The unique 2D/2D hetero-architecture provided numerous convenient nanochannels for charge transport, while sulfur doping introduced the impurity states and defects in SCN, which contributed to the enhanced visible-light absorption and efficient separation of photo-generated carriers. Besides, sulfur doping induced the distinct difference in Fermi levels and enhanced electronic coupling between TNS and SCN as evidenced by density functional theory calculations and X-ray photoelectron spectra, which facilitated the interfacial charge transport in heterojunction. The accelerated interfacial charge transport in TNS/SCN driven by the enhanced internal electric field promoted the efficient separation of photogenerated carriers. TNS/SCN can achieve excellent stability and reusability after four consecutive cycles, over a wide pH range or under coexisting anion conditions. Mechanisms toward the TC-HCl degradation and step-scheme interfacial charge transport were also proposed. This work provides a new strategy to enhance the catalytic performance of step-scheme heterojunction. [ABSTRACT FROM AUTHOR]