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A facile synthesis approach to fabricate Cu-doped MoS 2 /Bi 2 S 3 (Cu-MoS 2 /Bi 2 S 3 ) photocatalysts is reported. The photocatalyst samples with varying amounts of Cu are applied in the photocatalytic splitting of water to produce H 2 under the irradiation of simulated solar light. The Cu-MoS 2 /Bi 2 S 3 photocatalysts with an optimum Cu loading of 20 mol% exhibited high photocatalytic performance, achieving a total H 2 yield of 32.4 μmol/h after 6 h of reaction. The photoactivity of the Cu-doped sample was shown to have risen more than 40% than that of pure MoS 2 /Bi 2 S 3 . The improved performance is attributed to the impurity states generated within Cu-doped MoS 2 , which serve as trapping sites for photogenerated electrons. The effective charge transfer mechanism achieved was evidenced by photoelectrochemical measurements. Based on the experimental results obtained, a plausible mechanism for the photocatalytic process associated with Cu-MoS 2 /Bi 2 S 3 was proposed. [ABSTRACT FROM AUTHOR]

The photoreduction of carbon dioxide (CO 2 ) into hydrocarbon fuels was studied in a homemade photocatalytic system over 5 wt.% graphene oxide-doped oxygen-rich TiO 2 (5GO-OTiO 2 ) photocatalyst. The CO 2 transformation process is a sequential combination of both water oxidation and CO 2 reduction. As these processes can be affected by parameters such as radiant flux intensity and the partial pressures of both CO 2 and water vapour, these factors were systematically varied and studied in order to determine the most suitable process conditions for achieving high photocatalytic activity. Based on results from the CO 2 photoreduction experiments, a total methane (CH 4 ) yield of 3.450 μmol g cat −1 was successfully attained over 5GO-OTiO 2 after 8 h of reaction time under visible light irradiation. The experimental data obtained was then fitted into the Langmuir-Hinshelwood surface reaction mechanism, wherein both CO 2 and H 2 O adsorbed simultaneously on the photocatalyst surface to form the CH 4 product. Regression fitting was performed to determine the kinetic parameters such as reaction rate constant and adsorption equilibrium constants. The reaction rate as well as CO 2 and H 2 O adsorption equilibrium constants were determined to be 84.42 μmol g cat −1 h −1 , 0.019 bar −1 and 8.07 bar −1 , respectively. The significantly smaller CO 2 adsorption equilibrium constant implied that the adsorption of CO 2 was very weak while water strongly adsorbed on the photocatalyst surface. [ABSTRACT FROM AUTHOR]

Herein, visible-light-active oxygen-rich TiO 2 (O 2 -TiO 2 ) photocatalysts were synthesized via a facile and dopant-free strategy using different annealing temperatures ranging from 200 to 800 °C. The annealing treatment had important effects on the anatase–rutile phase composition, textural property and photocatalytic performance of O 2 -TiO 2 . The photoactivity of the samples were evaluated through the photocatalytic reduction of CO 2 under the irradiation of low-powered energy-saving daylight bulbs. O 2 -TiO 2 calcined at an optimum temperature of 300 °C (O 2 -TiO 2 -300) displayed the highest photocatalytic performance, achieving an enhancement factor of 12.2 and 11.2 over pure anatase TiO 2 and the commercial Degussa P25, respectively. Although the improvement in photoactivity could be attributed to the combined effect of several factors such as enhanced optical properties and high surface area of O 2 -TiO 2 -300, the findings from this work provided evidence that the optimum anatase–rutile phase composition in the sample played a dominant role in the enhancement of photocatalytic performance. Based on the experimental results obtained, a plausible mechanism for the charge transfer and separation process in O 2 -TiO 2 was also proposed. The present work could provide new insights into the architecture of oxygen-modified TiO 2 photocatalysts with markedly enhanced photocatalytic activities in energy- and environmental-related applications. [ABSTRACT FROM AUTHOR]

Herein, we present the successful synthesis of a new graphene oxide-doped-oxygen-rich TiO 2 (GO–OTiO 2 ) hybrid heterostructure through a facile wet chemical impregnation technique. The photocatalytic performances of all samples were evaluated through the photoreduction of CO 2 under the irradiation of low-power energy-saving daylight bulbs. Pure oxygen-rich TiO 2 (O 2 –TiO 2 ) was first prepared via a simple aqueous peroxo-titanate route. The as-prepared photocatalyst was shown to exhibit reduced band gap energy and visible-light-active characteristics. However, the photoactivity of bare O 2 –TiO 2 was found to gradually deteriorate over time. Hence, by exploiting its unique properties, graphene oxide (GO) was subsequently incorporated with the O 2 –TiO 2 photocatalyst. It was observed that the photostability of the resulting GO–OTiO 2 composite was significantly enhanced, where it maintained a reactivity of 95.8% even after 6 h of light irradiation. This observation firmly established the role of GO as an effective catalyst mat for O 2 –TiO 2 nanoparticles where it accepted photoinduced electrons and reduced the probability of charge recombination. In the CO 2 photoreduction experiments, 5GO–OTiO 2 with an optimum GO loading of 5 wt.%, exhibited the highest photoactivity, achieving a total CH 4 yield of 1.718 μmol/g cat after 6 h of reaction. The total product yield obtained over 5GO–OTiO 2 was found to be 14.0 folds higher in comparison to commercial Degussa P25. In overall, we systematically demonstrated an unprecedented proof-of-concept study on enhancing the photoactivity of GO–OTiO 2 via a combined strategy of fabricating visible-light-responsive O 2 –TiO 2 and increasing its photostability by incorporating GO sheets. [ABSTRACT FROM AUTHOR]

The design and architecture of visible-light-active photocatalysts is a key aim among material scientists for the efficient utilization of renewable solar energy. In this paper, a series of noble metal (Pt, Pd, Ag and Au) nanoparticles supported on reduced graphene oxide/TiO 2 (GT) were successfully synthesized through a dual step process. In the first step, GT nanocomposites were prepared using a solvothermal method. The as-prepared hybrid nanostructures were subsequently employed as supporting materials for the dispersion of metal nanoparticles. A simple polyol process was used to respectively reduce metal ions (PtCl 6 2− , Pd 2+ , Ag + , and AuCl 4 − ) into metal (Pt, Pd, Ag and Au) nanoparticles on GT. The three-component nanocomposites exhibited enhanced photocatalytic activities toward the photoreduction of CO 2 into CH 4 gas under the irradiation of typical daylight bulbs. This was attributed to the multiplex phenomena such as an enhanced utilization of visible light, efficient electron transfer in the noble metal-doped GT nanojunctions and interfacial electron transfer in the reduced graphene oxide (rGO) sheets, as evidenced by UV–vis and PL characterizations. Among the noble metals studied, the Pt-doped GT nanocomposites showed the highest efficiency in reducing CO 2 . A total CH 4 yield of 1.70 μmol/g cat was achieved after 6 h of light irradiation, which was 2.6 and 13.2 folds higher in comparison to GT and commercial P25, respectively. Based on the experimental results obtained, a plausible mechanism for the photocatalytic process associated with Pt-GT was proposed. [ABSTRACT FROM AUTHOR]

Abstract: The conventional method to synthesize carbon nanotubes (CNTs) requires the use of metallic catalysts. However, the metallic particle impurities usually contaminate the CNTs, and are difficult to remove without introducing defects and contaminations. An alternative and more desirable approach is to grow CNTs directly on a substrate without further treatment being required. The review presents and discusses the current development of the controlled synthesis of SWCNTs and/or MWCNTs using non-metallic catalysts, which comprises of various ceramics and semiconductors as catalytic particles. All-carbon systems for CNT growth without employing any catalysts are also discussed. Despite the enormous strides in the synthesis of CNTs, the precise atomistic mechanism explaining their nucleation and growth still remains unclear. Therefore, the different growth systems proposed by several authors are also examined in this article. The review concludes with a summary and an outlook on the challenges and future directions in the metal-free-catalyst growth of CNTs. [Copyright &y& Elsevier]

Abstract: The preparation of SiO2 nanoparticles for the metal-free catalyst growth of carbon nanotubes (CNTs) was investigated. SiO2 nanoparticles were generated by etching Si/SiO2 wafers with 48–50% hydrofluoric acid. Etching duration was varied to study its effects on the generation of the SiO2 nanoparticles. Atomic force microscopy characterization showed that etching at 1min was the most effective considering the significant numbers of SiO2 nanoparticles obtained under this condition. The wafer etched at 1min after chemical vapor deposition at 900°C for 1h demonstrated a low I D/I G from Raman analysis which establishes that CNTs with highly ordered graphitic structures were grown. Raman analysis also showed a strong radial breathing mode peak in the low-frequency range for the substrate following the 1min etching process after the reaction. [Copyright &y& Elsevier]

Despite the significant milestones in the half‐reduction process of photocatalysis, challenges remain in fully utilizing electron–hole pairs in the simultaneous redox reactions. Herein, a Z‐scheme ZnIn2S4/W18O49 (ZW) hybrid with complementary band edge potential is in situ constructed. The resultant fuzzy 1D‐assembled sea‐urchin photocatalyst demonstrates an optimal H2 and benzaldehyde yield of 122 and 106 µmol h−1 under λ > 420 nm light irradiation. This sacrificial‐agent‐free system entails solar‐to‐hydrogen (STH) and apparent quantum efficiency (AQE) values of 0.466% and 2.48% (420 nm), respectively, surpassing most of the recently reported photocatalytic systems without the aid of noble metal cocatalysts. The outstanding performance is mainly attributed to the synergistic formation of intimate Z‐scheme heterojunction and the induction of localized surface plasmon resonances. Comprehensive characterization studies prove the direct injection of energetic hot electrons to promote the number of long‐lived active electrons. Besides, electron paramagnetic resonance and scavenger tests clarify the complicated mechanistic puzzle of the dual‐redox reaction, where benzaldehyde is formed dominantly via O─H activation followed by C─H cleavage of benzyl alcohol over ZW hybrid. Lastly, the universal use of the ZnIn2S4/W18O49 composites is testified in various dual‐redox systems. This study offers a novel outlook for designing dual‐functioning heterojunctions toward a feasible photoredox application. [ABSTRACT FROM AUTHOR]

Growing concerns of water pollution by dye pollutants from the textile industry has led to vast research interest to find green solutions to address this issue. In recent years, heterogeneous photocatalysis has harvested tremendous attention from researchers due to its powerful potential applications in tackling many important energy and environmental challenges at a global level. To fully utilise the broad spectrum of solar energy has been a common aim in the photocatalyst industry. This study focuses on the development of an efficient, highly thermal and chemical stable, environmentally friendly and metal-free graphitic carbon nitride (g-C 3 N 4) to overcome the problem of fast charge recombination which hinders photocatalytic performances. Nitrogen-doped carbon quantum dots (NCQDs) known for its high electronic and optical functionality properties is believed to achieve photocatalytic enhancement by efficient charge separation through forming heterogeneous interfaces. Hence, the current work focuses on the hybridisation of NCQDs and g-C 3 N 4 to produce a composite photocatalyst for methylene blue (MB) degradation under LED light irradiation. The optimal hybridisation method and the mass loading required for maximum attainable MB degradation were systematically investigated. The optimum photocatalyst, 1 wt% NCQD/g-C 3 N 4 composite was shown to exhibit a 2.6-fold increase in photocatalytic activity over bare g-C 3 N 4. Moreover, the optimum sample displayed excellent stability and durability after three consecutive degradation cycles, retaining 91.2% of its original efficiency. Scavenging tests were also performed where reactive species, photon-hole (h+) was identified as the primary active species initiating the pollutant degradation mechanism. The findings of this study successfully shed light on the hybridisation methods of NCQDs which improve existing g-C 3 N 4 photocatalyst systems for environmental remediation by utilising solar energy. Image 1 • Nitrogen-doped CQDs were hybridized with g-C 3 N 4 through a facile synthesis approach. • The NCQD/g-C 3 N 4 hybrid showed high efficiency toward MB degradation under LED light. • The best hybridization approach and the effect of NCQD loading on g-C 3 N 4 were studied. • The optimum 1 wt% NCQD/g-C 3 N 4 exhibited a 2.6-fold increase in activity over g-C 3 N 4. • A plausible photocatalytic mechanism over NCQD/g-C 3 N 4 hybrid composite was proposed. [ABSTRACT FROM AUTHOR]

Sunlight‐driven CO2 conversion into value‐added fuels emerges as an avant‐garde strategy to mitigate the imminent energy scarcity and global warming. Nevertheless, sluggish charge kinetics and rapid carrier recombination are deemed as the foremost bottlenecks of efficient CO2 photoreduction. In this contribution, the aforementioned shortcomings are addressed by assembling a homo–hetero architecture comprising oxygen‐defective ultrathin BiVO4 (BiVO4–Ov) and red/black phosphorus (RP/BP) homojunction with a built‐in nanoscale dual Z‐scheme electronic configuration. The development of BiVO4–Ov@RP/BP confers two electron relaying channels, that is, one from the RP/BP homojunction and another from the BiVO4–Ov/RP heterojunction, which warrant the efficient separation of electron–hole pairs. Besides, the ultrathin 2D and oxygen vacant nature of BiVO4–Ov exposes more active sites and renders electron trapping for efficient utilization of photogenerated charges. Amalgamating the desirable properties, the meticulously developed dual Z‐scheme homo–heterojunction system on the basis of surface defect‐engineered ultrathin BiVO4–Ov nanosheets integrated with RP/BP offers a new avenue for the exploration, design, and fabrication of new generation photocatalysts with exceptional photocatalytic activities. In particular, the BiVO4–Ov@RP/BP system demonstrates a remarkably high CH4 yield of 14.52 μmol g−1 after 6 h of visible light illumination, which resembles a leading‐edge photocatalytic performance among the existing BiVO4‐ and P‐based semiconductors. [ABSTRACT FROM AUTHOR]

Photocatalytic conversion of carbon dioxide (CO2) into value‐added fuels is a vastly promising anthropogenic chemical carbon cycle to combat the greenhouse effect while meeting the ever‐increasing energy demand. Recently, lead‐based halide perovskites have demonstrated great potential in various applications including photochemical reduction of CO2. However, in view of lead toxicity, the exploration of a lead‐free alternative is crucial for long term application. Herein, a series of lead‐free mixed halide perovskites Cs3Sb2ClxBr9−x (0 ≤ x ≤ 9) is prepared via a facile antisolvent recrystallization technique, where the incorporation of a secondary halide enhances the charge transfer and separation while allowing precise tuning of bandgap between 2.59 and 2.90 eV. Theoretical calculations further reveal that the formation of mixed Cl/Br halides engenders favorable charge redistribution due to lower octahedral distortion, which in turn strengthens CO2 adsorption and activation. Under visible light illumination, the optimal dual halide perovskite, Cs3Sb2Cl4Br5 manifests substantial twofold and fourfold enhancements of CH4 yield over the single halide perovskite, Cs3Sb2Br9 and Cs3Sb2Cl9, respectively. In brief, this study provides a compelling demonstration of lead‐free mixed halide perovskites for photocatalytic CO2 reduction, and it is anticipated to drive further application of perovskite‐based photocatalysts toward a diverse range of artificial photoredox reactions. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide quantum dots (MoS 2 QDs) decorated bismuth sulfide (Bi 2 S 3 ) photocatalyst was synthesized. Photoluminescence characterization showed that the as-developed MoS 2 QDs possessed intriguing up-conversion and down-conversion properties, indicating their capability to harness energy from the light spectrum ranging from ultraviolet (UV) to near-infrared (NIR). In this study, the highest hydrogen yield of 17.7 mmol/g.h was achieved by 0.14MoS 2 QD/Bi 2 S 3 , which was almost 4.5 folds higher than that of undoped Bi 2 S 3 under stimulated solar light irradiation. Furthermore, examination of the 0.14MoS 2 QD/Bi 2 S 3 photocatalysts under NIR irradiation showed a significant photocurrent response and an accumulative H 2 yield of 53.6 μmol/g after 6 h reaction. This is a major breakthrough as most photocatalysts can only be activated under UV and/or visible light irradiation. This work provides new insights into the design of MoS 2 QD/Bi 2 S 3 for harnessing energy from a broad solar spectrum to photocatalytically split water to produce hydrogen. [ABSTRACT FROM AUTHOR]

Review: [177 refs. [ABSTRACT FROM AUTHOR]

Review: 121 refs. [ABSTRACT FROM AUTHOR]

To overcome rapid electron-hole recombination and the need for employing noble metals as co-catalysts for photocatalytic water splitting, the present work reports on the fabrication of bismuth sulphide (Bi 2 S 3 )-modified molybdenum disulphide (MoS 2 ) as an efficient hybrid photocatalyst. Under simulated solar light irradiation, the Bi 2 S 3 /MoS 2 photocatalyst with an optimum molar ratio of Mo to Bi of 50% (mol/mol) achieved a H 2 production rate of 61.4 μmol/h. The photocatalytic enhancement was attributed to an effective charge transfer mechanism between Bi 2 S 3 and MoS 2 , as evidenced by photoelectrochemical characterization. A plausible reaction mechanism over the as-prepared Bi 2 S 3 /MoS 2 photocatalyst was also proposed based on the experimental results obtained. [ABSTRACT FROM AUTHOR]

In this contribution, the effectiveness of tailor-made multi-walled carbon nanotubes (MWCNTs) as a solid-state electron mediator for facilitating Z-schematic water splitting is demonstrated. An anisotropic Zn 0.5 Cd 0.5 S-MWCNT-TiO 2 ternary core-shell nanocomposites fabricated by a facile coating and hydrothermal route renders a much higher photocatalytic activity than the corresponding single- and two-component systems, revealing MWCNTs can shuttle photogenerated electrons from PS II (TiO 2 ) to PS I (Zn 0.5 Cd 0.5 S). This unique type of vectorial electron transfer between the two photosystems imparts an efficient spatial charge isolation and endows suitable relative band positions with strong redox ability to the Z-scheme system. Consequently, the simulated solar-light-driven (AM 1.5) photocatalytic H 2 evolution rate of the as-prepared Zn 0.5 Cd 0.5 S-MWCNT-TiO 2 photocatalyst (21.9 μmol h −1 ) is ca. 4.5- and 2.8-fold enhancement over pristine Zn 0.5 Cd 0.5 S and MWCNT-Zn 0.5 Cd 0.5 S samples, respectively. The structural and chemical properties of the typical photocatalysts were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and ultraviolet–visible diffuse spectroscopy (UV–Vis). Besides, electrochemical characterizations (transient photocurrent, Nyquist and Mott-Schottky measurements) were performed to depict the ascendency of the Z-scheme system. Based on the outcomes of the experiment, a plausible charge transfer mechanism for the Z-schematic Zn 0.5 Cd 0.5 S-MWCNT-TiO 2 system was postulated. [ABSTRACT FROM AUTHOR]

ZnIn2S4 (ZIS) is an efficient photocatalyst for solar hydrogen (H2) generation from water splitting owing to its suitable band gap, excellent photocatalytic behaviour and high stability. Nevertheless, modifications are still necessary to further enhance the photocatalytic performance of ZIS for practical applications. This has led to our interest in exploring phosphorus doping on ZIS for photocatalytic water splitting, which has not been studied till date. Herein, phosphorus-doped ZnIn2S4 (P-ZIS) was modelled via Density Functional Theory to investigate the effects of doping phosphorus on the structural and electronics properties of ZIS as well as its performance toward photocatalytic water splitting. This work revealed that the replacement of S3 atom by substitutional phosphorus gave rise to the most stable P-ZIS structure. In addition, P-ZIS was observed to experience a reduction in band gap energy, an upshift of valence band maximum (VBM), an increase in electron density near VBM and a reduction of H* adsorption–desorption barrier, all of which are essential for the enhancement of the hydrogen evolution reaction. In overall, detailed theoretical analysis carried out in this work could provide critical insights towards the development of P-ZIS-based photocatalysts for efficient H2 generation via solar water splitting. [ABSTRACT FROM AUTHOR]

In this work, visible-light-active silver halide AgX(X = Cl and Br) deposited on the protonated graphitic carbon nitride (pCN) photocatalyst was developed by a sonication-assisted deposition-precipitation route at room temperature. The surface morphology, phase structure, chemical composition, optical property and electronic band structures of the AgX-hybridized pCN (AgX/pCN) hybrid nanocomposites were systematically characterized. Subsequently, the photocatalytic performance of the AgX/pCN was evaluated by the reduction of CO 2 to CH 4 in the presence of H 2 O vapor under a low-power energy-saving daylight bulb at atmospheric pressure and ambient temperature. The optimal 30AgBr/pCN presented the highest photocatalytic activity, achieving a total CH 4 evolution of 10.92 μmol g catalyst −1 , which was 34.1 and 4.2 times greater than those of single-phase AgBr and pCN, respectively. Furthermore, by comparing different halide ions, the photoactivity of 30AgBr/pCN was higher (by a factor of 1.3) than that of the optimal 30AgCl/pCN. The enhanced photocatalytic activity was accredited to (1) the surface plasmon resonance (SPR) effect from Ag and (2) the formation of heterojunction structure between pCN and AgBr in the AgBr/pCN hybrid photocatalysts for efficient charge transfer and separation to retard the recombination process as evidenced by the photoluminescence analysis. The effective charge separation was attributed to the matching of electronic band potentials of pCN and AgBr, exhibiting the Type II heterojunction, in comparison to that of AgCl/pCN (Type I heterojunction). Lastly, the plasmon-enhanced photocatalytic mechanisms associated with both Ag/AgBr/pCN and Ag/AgCl/pCN hybrid nanoarchitectures were critically discussed. [ABSTRACT FROM AUTHOR]

ZnIn2S4 (ZIS) is an efficient photocatalyst for solar hydrogen (H2) generation from water splitting owing to its suitable band gap, excellent photocatalytic behaviour and high stability. Nevertheless, modifications are still necessary to further enhance the photocatalytic performance of ZIS for practical applications. This has led to our interest in exploring phosphorus doping on ZIS for photocatalytic water splitting, which has not been studied till date. Herein, phosphorus-doped ZnIn2S4 (P-ZIS) was modelled via Density Functional Theory to investigate the effects of doping phosphorus on the structural and electronics properties of ZIS as well as its performance toward photocatalytic water splitting. This work revealed that the replacement of S3 atom by substitutional phosphorus gave rise to the most stable P-ZIS structure. In addition, P-ZIS was observed to experience a reduction in band gap energy, an upshift of valence band maximum (VBM), an increase in electron density near VBM and a reduction of H* adsorption–desorption barrier, all of which are essential for the enhancement of the hydrogen evolution reaction. In overall, detailed theoretical analysis carried out in this work could provide critical insights towards the development of P-ZIS-based photocatalysts for efficient H2 generation via solar water splitting. [ABSTRACT FROM AUTHOR]

Universal access to clean water has been a global ambition over the years. Photocatalytic water disinfection through advanced oxidation processes has been regarded as one of the promising methods for breaking down microbials. The forefront of this research focuses on the application of metal‐free photocatalysts for disinfection to prevent secondary pollution. Graphitic carbon nitride (g‐C3N4) has achieved instant attention as a metal‐free and visible‐light‐responsive photocatalyst for various energy and environmental applications. However, the photocatalytic efficiency of g‐C3N4 is still affected by its rapid charge recombination and sluggish electron‐transfer kinetics. In this contribution, two‐dimensionally protonated g‐C3N4 was employed as metal‐free photocatalyst for water treatment and demonstrated 100 % of Escherichia coli within 4 h under irradiation with a 23 W light bulb. The introduction of protonation can modulate the surface charge of g‐C3N4; this enhances its conductivity and provides a "highway" for the delocalization of electrons. This work highlights the potential of conjugated polymers in antibacterial application. [ABSTRACT FROM AUTHOR]

The engineering of surface oxygen vacancies (OVs) in WO3 was primitively done using a facile solvothermal method. The photocatalytic activities of the as-prepared samples were studied by evaluating their performances in the photocatalytic OER. The best sample (W-3) yielded 57.6 μmol of O2 in 6 h under the illumination of simulated sunlight. [ABSTRACT FROM AUTHOR]

Recently, tetracycline (TC) is classified as an emerging contaminant due to its rapid discharge into the environment from anthropogenic sources. Piezophotocatalysis offers a unique solution to degrade TCs by collaboratively harnessing both solar and hydro energy. However, practical applications have been hampered by the necessitation of high energy requirement ultrasonic baths. In this work, BT-KNN conjugates were investigated for piezophotocatalytic TC degradation. Under agitation conditions, characterization studies demonstrated an amplified photocurrent, diminished charge transfer resistance and reduced radiative recombination. Concomitantly, BT-KNN composites exhibit enhanced TC degradation and apparent rate constant with increased fluid disturbance frequencies, illustrating 91.3% degradation in 3 h under gentle 4 Hz oscillations. These hydrodynamic disturbances engender a propitious piezopolarization which modulated the junction band bending and ameliorated the interfacial charge transfer, intensifying its performance. Optimization studies further illustrates the tradeoff dynamics between high photoactivity of BT and high piezo-enhancement of KNN. [Display omitted] • BT-KNN conjugates engender built-in electric fields from Fermi equilibration. • Piezo-phototronic effect of BT-KNN augments optoelectronic properties. • TC degradation and rate constants were enhanced under gentle disturbances. • Piezopolarization modulated band bending interfacial charge transfer characteristics. • Optimization studies depict the quintessential tradeoff dynamics of BT and KNN. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is an indispensable chemical that serves as a key precursor in the production of a wide array of commercially essential nitrogenous compounds. The catalytic conversion of nitrogen (N 2) to NH 3 is a kinetically complicated and energetically demanding reaction. In this regard, the inception of photocatalytic N 2 fixation which operates under mild conditions holds great promise as a sustainable alternative to the conventional Haber-Bosch process. Herein, defective bismuth-rich oxychloride with oxygen vacancies (BOC-OV) was synthesized and optimized for N 2 photo-fixation. The fabrication encompassed a two-step hydrothermal and post-synthesis inert annealing for the induction of oxygen vacancies (OVs). Through the introduction of OVs, the bismuth-rich photocatalyst garnered a massively improved photo-absorption range, enhanced charge dynamics, and increased efficiency of charge separation. The defects generated also provided an abundance of active sites to ease N 2 adsorption and overcome the energy barrier for the activation of N 2 molecules. The defect-rich BOC-OV sample exhibited a notable NH 3 generation rate of 23.43 µmol g cat -1 h-1 in pure water under solar irradiation. On the basis of the experimental findings, this study discloses insights into the rational engineering of OVs and presents the OV-induced bismuth-rich oxychloride as a promising material for the realization of a highly efficient and sustainable photo-driven N 2 fixation system. [Display omitted] • Optimization of defective bismuth-rich oxychloride for highly-efficient N 2 photo-fixation. • Defects provided active sites in easing N 2 adsorption. • Oxygen vacancies aids the overcoming of energy barrier for N 2 activation. • Disclosing insights into OVs engineering for a sustainable photo-driven N 2 system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two-dimensional interface engineering of isotype g-C3N4/g-C3N4 p-n heterojunctions. • Intimate interfacial contact was formed at the isotype phase junction. • p-n junction expedited interfacial charge transfer via a reinforced electric field. • g-C3N4/g-C3N4 heterostructures displayed exceptional photoreduction of CO2 to CH4. The creation of an isotype phase junction has been recognized as an effective means of improving the spatial charge separation and migration in g-C 3 N 4 materials. Nevertheless, due to a lack of electrostatic control in the internal electric field, isotype heterojunction alone is incapable of providing a sufficient driving force to maximize charge carrier transfer. Herein, we present an interface engineering strategy for co-integrating isotype and p-n heterojunctions to fabricate g-C 3 N 4 /g-C 3 N 4 nanohybrids using a facile ultrasonic-assisted self-assembly method. The coherent boundary between the two distinct phases of g-C 3 N 4 demonstrates that an intimate 2D interfacial contact can be easily established by π-π stacking interactions because of their high structural similarities and low lattice strain. Furthermore, their compatible and well-matched electronic band structures led to a staggered type II alignment in the lateral heterojunction, which confers the resulting composite with strong redox ability, efficient exciton dissociation, and desirable optoelectronic characteristics beyond those of the two constituents. Essentially, the isotype and p-n heterojunctions work in tandem to create a robust built-in electric field, allowing for effective interfacial charge steering for directional electron migration from BCN to CN x. Benefiting from these merits, the BCN/CN x nanohybrid manifested remarkable CH 4 generation from photocatalytic CO 2 reduction, outperforming its CN x and BCN counterparts by 1.91 and 6.88-fold, respectively. The midgap states induced by nitrogen defects in CN x also pose a positive effect on the improved photoactivity of the binary composite by acting as an electron reservoir to mediate electron transfer and further impede charge carrier recombination. This proof-of-concept study highlights the significance of interface engineering in charge flow manipulation and utilization for photocatalytic enhancement. [ABSTRACT FROM AUTHOR]

Construction of heterojunction is conventionally regarded as the prevailing technique to render effective solar-driven photocatalytic water splitting. Nonetheless, realization of p-n homojunction emerges to be an appealing scheme attributed to the non-defective layer coupling and minor charge transfer impedance. Herein, nitrogen-doped ZnIn 2 S 4 (N-ZIS) with dual p-n charge properties was facilely synthesized via one-step in-situ solvothermal method. Systematic investigations unveil that the substituting phenomenon of hosting S by extrinsic N atom with dissimilar electronegativity and valence electron, which eventually ameliorates charge transfer rate and inhibits electron-hole pairs recombination. First-principle density functional theory calculations affirm the p-nature induced by N-doping imparting favorable charge redistribution in the ZIS framework and diminishing hydrogen (H 2) evolution reaction kinetic barrier at the surface-active sites. Therein, optimal N-ZIS generated 1575.71 μmol∙g−1 of H 2 under 6-hour visible-light irradiation (with an apparent quantum yield of 6.59 % at 420 nm monochromatic light irradiation), which is 6.35-fold than the pristine counterpart. [Display omitted] • Elemental-doping induced dual p-n charge nature within single ZnIn 2 S 4 structure enhances photocatalytic hydrogen production. • N-dopant ameliorates charge transfer and inhibits electron-hole pair recombination in ZnIn 2 S 4. • First-principle density functional theory affirms favourable charge redistribution and diminished hydrogen evolution kinetic barrier in N-doped ZnIn 2 S 4. [ABSTRACT FROM AUTHOR]

In the present work, two-dimensional bismuth oxybromide (BiOBr) was synthesized and coupled with co-catalyst molybdenum disulphide (MoS 2 ) via a simple hydrothermal process. The photoactivity of the resulting hybrid photocatalyst (MoS 2 /BiOBr) was evaluated under the irradiation of 15 W energy-saving light bulb at ambient condition using Reactive Black 5 (RB5) as model dye solution. The photo-degradation of RB5 by BiOBr loaded with 0.2 wt% MoS 2 (MoBi-2) exhibited more than 1.4 and 5.0 folds of enhancement over pristine BiOBr and titanium dioxide (Degussa, P25), respectively. The increased photocatalytic performance was a result of an efficient migration of excited electrons from BiOBr to MoS 2 , prolonging the electron-hole pairs recombination rate. A possible charge transfer diagram of this hybrid composite photocatalyst, and the reaction mechanism for the photodegradation of RB5 were proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Blue TiO 2 showed an impressive enhancement of diesel degradation compared to pristine TiO 2. • Oxygen vacancy mid gap states increased optical absorption and photocatalyst charge density. • Mid gap states augment the separation of electron hole pairs by acting as trap states. • Restructuring of alkane distribution in diesel occurred after degradation. • Short chain alkanes, alkenes, alcohols and cycloalkanes were the products of degradation. The proliferation of marine petroleum exploitation has culminated in the undesired release of oils into the aquatic ecosystem, causing detrimental environmental effects. Photocatalysis proffers a solution to degrade recalcitrant diesel oil utilizing abundant solar energy, in which TiO 2 is the perennial photocatalyst of choice. However, it suffers from the low utilization of the light spectrum and the rapid recombination of photogenerated charge carriers. In this work, oxygen-vacancy-rich blue TiO 2 was employed to overcome the shortcomings of TiO 2 in diesel oil degradation which has historically not been attempted. These oxygen vacancies induce favourable mid gap states to extend the optical absorption capabilities and enrich the photocatalyst charge density. Additionally, oxygen vacancies enhance the separation of electron hole pairs by acting as trap states, evident from increased trap-mediated capture fluorescence. Consequently, a 1.60-fold enhancement of diesel oil degradation performance compared to pristine TiO 2 was observed. Mechanistic insights revealed the restructuring of diesel alkane distribution upon degradation corollary to the cleavage of hydrocarbon chains, illustrating that short alkanes experience a greater susceptibility to degradation compared to long alkanes. GC–MS analysis elucidates that shorter chained alkanes, alkenes, alcohols and cycloalkanes were produced as a product of the degradation. [ABSTRACT FROM AUTHOR]

• Breaking of intermolecular bonding enhanced photocatalytic performance of GCN. • Defects in crystallinity induced mid-gap states. • Existence of a mid-gap state in ACN supplied a secondary H+/H 2 reduction site. • The optimum ACN sample displayed activity 2-fold higher than that of pristine GCN. In this work, the intramolecular structure of a pristine graphitic carbon nitride (GCN) was modified to investigate how it would affect the photocatalytic activity towards hydrogen evolution reaction (HER) under simulated solar irradiation. The intramolecular bonding of GCN was broken by subjecting it to a simple thermal treatment under a controlled environment. Both experimental and computational studies revealed that removal of inter-heptazine CN(H)C groups from the pristine structure induced an amorphous phase and additional energy bands to GCN. It was also observed that a mid-gap state was formed between the conduction band (CB) of the amorphous carbon nitride (ACN) and the H+/H 2 reduction potential. The presence of the mid-gap state not only served as an additional reduction site for HER, but also acted as a buffer to reduce the recombination rate of photogenerated charge carriers. The optimum ACN sample displayed an enhanced photocatalytic performance achieving a HER rate of 789 µmol/g cat , which was about 2-fold higher than that of pristine GCN. This could be ascribed to the synergistic effect of improved light absorption, increased surface area, suppressed charge recombination and increased charge carrier densities for the ACN samples to drive the overall reduction–oxidation process. [ABSTRACT FROM AUTHOR]