Polarization-sensitive ultraviolet (UV) photodetection is of great technological importance for both civilian and military applications. Two-dimensional (2D) group-10 transition-metal dichalcogenides ...(TMDs), especially palladium diselenide (PdSe2), are promising candidates for polarized photodetection due to their low-symmetric crystal structure. However, the lack of an efficient heterostructure severely restricts their applications in UV-polarized photodetection. Here, we develop a PdSe2/GaN Schottky junction by in situ van der Waals growth for highly polarization-sensitive UV photodetection. Owing to the high-quality junction, the device exhibits an appealing UV detection performance in terms of a large responsivity of 249.9 mA/W, a high specific detectivity, and a fast response speed. More importantly, thanks to the puckered structure of the PdSe2 layer, the device is highly sensitive to polarized UV light with a large dichroic ratio up to 4.5, which is among the highest for 2D TMD material-based UV polarization-sensitive photodetectors. These findings further enable the demonstration of the outstanding polarized UV imaging capability of the Schottky junction, as well as its utility as an optical receiver for secure UV optical communication. Our work offers a strategy to fabricate the PdSe2-based heterostructure for high-performance polarization-sensitive UV photodetection.
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•Ti3C2 MXene@TiO2/CuInS2 Schottky/s-scheme integrated heterojunctions were prepared by a two-step hydrothermal method.•Synergistic effect of Schottky junction and s-scheme ...heterojunction endows significantly improved charge transfer.•The ternary heterojunction shows excellent photocatalytic hydrogen production and outstanding cycling stability.•The photocatalytic mechanism was clarified by some representative characterizations.
The development of novel and efficient heterojunction photocatalysts is still a challenging issue for achieving highly efficient solar-to-chemical energy conversion. Herein, we report the construction of Ti3C2 MXene@TiO2/CuInS2 (M@T/CIS) integrated Schottky/step-scheme (S-scheme) heterojunction by two-step hydrothermal process for boosting photocatalytic hydrogen generation activity. The as-prepared M@T/CIS hybrid photocatalysts exhibit the synergistic effects for enhanced visible-light harvesting, improved charge transfer and increased active site for photocatalytic H2 evolution. They deliver a H2 evolution rate of 356.27 μmol g-1h−1, which is ∼ 69 and 636 times higher than those of M@T and CIS, respectively, representing their potential applications towards photocatalytic H2 evolution.
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Facing the demand of cleaning energy, the development of efficient photocatalysts for hydrogen evolution is a promising way to realize solar-to-chemical energy conversion for solving ...energy crisis. Hence, a novel hierarchical Ti3C2 MXene@TiO2/ZnIn2S4 photocatalyst with rapid charge transfer channels was constructed by two-step hydrothermal for efficient hydrogen production, adopting hydrothermal oxidation to in-situ synthesize Ti3C2 MXene embedded with TiO2 nanosheets (M@TiO2), which was applied to load ZnIn2S4 (ZIS). The hybridized photocatalyst with optimized ZIS amount had a hydrogen generation rate of 1185.8 μmol/g/h, which was higher than that of M@TiO2 and pure ZIS. That was originated from the outstanding light harvesting of ZIS and Ti3C2, sufficient active sites of Ti3C2, intimate interfacial contact, and efficient separation and transfer of photogenerated charges via heterojunction. The favorable and rapid charge transfer routes included type-II heterojunction between ZIS and TiO2 nanosheets, Schottky junction of Ti3C2/semiconductor, and metallic Ti3C2 with high conductivity. This work revealed the Schottky junction forming between ZIS and Ti3C2, and hierarchical M@TiO2 could be served as advantageous platform and efficient cocatalyst to construct MXene-based photocatalyst.
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•The MXene/Ag2S catalyst is constructed by chemical deposition and electrostatically driven self-assembly.•The MXene/Ag2S has excellent visible light absorption performance under ...visible light (>420 nm).•The prepared photocatalyst can efficiently remove MB and tetracycline hydrochloride, with a removal rate of >90%.•Under the influence of mixed dyes and inorganic salts, the photocatalytic effect of the catalyst is still significant.•After 8 cycles of experiments, the photocatalytic activity is >90%.
A novel visible-light-driven uniform Schottky junction MXene/Ag2S catalyst is constructed by chemical deposition and electrostatically driven self-assembly to deposit Ag2S 3D MXene gel’s surface. In this study, various characterization tests show that MXene/Ag2S-2 photocatalyst has excellent visible light absorption performance under visible light (>420 nm). To explore the source of the excellent charge separation performance of Schottky junction, possible charge transfer mechanisms of Schottky junction, and the synergistic effect of silver ion plasmon resonance effect are proposed. We proved the charge transfer mechanism of the Schottky junction and also captured the active species capture experiments. It can be speculated that all active species affect the photocatalytic reaction in the order of O2− > e− > h+ >OH. Simultaneously, the photocatalytic system would have a small amount of silver ion reduction in the plasmon resonance effect during the photocatalysis process, which can be synergistic with the Schottky junction. Besides, the Schottky junction MXene/Ag2S has relatively stable photocatalytic performance and recovery capability. The current work demonstrates a mild, feasible, low-cost all-solid-state Schottky junction synthesis method to improve pollutants’ photocatalytic ability.
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•Integration of S-scheme/Schottky junctions and oxygen vacancies on SrTiO3 is constructed.•Formed junctions enable the transfer of charges with direction.•Designed hybrid dramatically ...improves photocatalytic H2 evolution activity.•Large-scale photocatalytic device (20 cm × 20 cm) is successfully demonstrated.
The interfacial design and defect engineering are of huge interest for achieving efficient photocatalytic H2 evolution using solar energy. In this work, we successfully integrated the Schottky junction and S-scheme heterojunction with oxygen vacancies to achieve the defective Ru/SrTiO3/TiO2 hybrid photocatalyst. As verified by experimental studies, these junctions with defects fully exploit the benefits of interfacial charge separation and transport. It is demonstrated that the designed hybrid exhibits dramatically enhanced photocatalytic H2 evolution rate with respect to pristine SrTiO3, high apparent quantum efficiency at 365 nm irradiation as well as excellent stability. Furthermore, the Ru/SrTiO3/TiO2 based device photocatalyst also displays the excellent H2 evolution activity with easy recycle nature. This finding provides a newfangled thought for developing highly efficient hybrid materials for photocatalytic H2 evolution.
•The Schottky connection between MoB2 and g-C3N4 allows for faster separation of photoexcited electron-hole pairs.•The addition of MoB2 to g-C3N4 improves its reduction ability, resulting in more ...efficient H2 production.•The light absorption ability of g-C3N4 is improved via modification with MoB2.•MoB2@g-C3N4 composite photocatalysis shows excellent photocatalytic hydrogen production activity.
The g-C3N4 material, which exhibits a sensitivity to visible light and has a band position that is appropriate for the photoreduction of H2, has garnered significant interest. However, the ability of g-C3N4 to use light for photocatalysis is restricted due to its insufficient capacity to absorb light and its poor reaction kinetics on the surface. The researchers opted for the metallic MoB2 to create a Schottky junction coupled with g-C3N4. The incorporation of MoB2 nanoparticles onto g-C3N4 enhances its light absorption capacity and promotes the efficient separation and transfer of photogenerated charge. In addition, MoB2 nanoparticles served as active sites to accelerate H2 evolution. Compared to g-C3N4, the MoB2@g-C3N4 composite exhibited a nearly 51-fold increase in H2 production rate, indicating a significant improvement in photocatalytic activity. The present investigation demonstrated the potential of metallic MoB2 as a modified material during a photocatalytic H2 evolution reaction.
The semiconducting ZnO photosensitizer and the metalloid Ni3ZnC0.7 catalyst are chemically bonded through oxygen-atom bridges, thereby expediting the photogenerated electron flow from ZnO to ...Ni3ZnC0.7, regulating the electron cloud density at the catalytic sites, and facilitating the conversion of *COOH-CO.
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•Znoxide–O–ZnTMC structure was constructed via ligand competition of MOF.•Znoxide–O–ZnTMC integrates photoexcitation, reaction sites and electron transport channels.•Znoxide–O–ZnTMC modulates the surface electron density distribution.•Znoxide–O–ZnTMC structure promotes the conversion of *COOH–CO products.•CO yield was 2674.8 μmol g-1h−1 with selectivity of 93.4 %.
Developing carbon dioxide (CO2) photocatalysts from transition metal carbides (TMCs) with abundant active sites, modulable electron cloud density, as well as low cost and high stability is of great significance for artificial photosynthesis. Building an efficient electron transfer channel between the photo-excitation site and the reaction-active site to extract and steer photo-induced electron flow is necessary but challenging for the highly selective conversion of CO2. In this study, we achieved an oxygen-bridged Schottky junction between ZnO and Ni3ZnC0.7 (denoted as Znoxide–O–ZnTMC) through a ligand-vacancy strategy of MOF. The ZnO–Ni3ZnC0.7 heterostructure integrates the photo-exciter (ZnO), high-speed electron transport channel (Znoxide–O–ZnTMC), and reaction-active species (Ni3ZnC0.7), where Znoxide–O–ZnTMC facilitates the transfer of excited electrons in ZnO to Ni3ZnC0.7. The Zn atoms in Ni3ZnC0.7 serve as electron-rich active sites, regulating the CO2 adsorption energy, promoting the transformation of *COOH to CO, and inhibiting H2 production. The ZnO–Ni3ZnC0.7 shows a high CO yield of 2674.80 μmol g–1h–1 with a selectivity of 93.40 % and an apparent quantum yield of 18.30 % (λ = 420 nm) with triethanolamine as a sacrificial agent. The CO production rate remains at 96.40 % after 18 h. Notably, ZnO–Ni3ZnC0.7 exhibits a high CO yield of 873.60 μmol g–1h–1 with a selectivity of 90.20 % in seawater.
•Ru0.7Cu0.3/W18O49 Schottky junction is synthesized.•Metallic Ru0.7Cu0.3 exhibits LSPR effects, enhancing AB hydrolysis activity.•The photocatalytic mechanism for H2 generation is systematically ...expounded.
Photocatalytic hydrogen (H2) production from ammonia borane (AB) hydrolysis is a promising pathway for generating clean energy. Constructing appropriate heterojunctions represents an efficient strategy for enhancing the catalytic activity. Herein, a Ru0.7Cu0.3/W18O49 Schottky junction is successfully designed, which greatly enhances transfer and separation of photogenerated charge carriers. Moreover, the metallic Ru0.7Cu0.3 exhibits localized surface plasmon resonance (LSPR), which greatly enhances the light harvesting capability. As expected, the optimized Ru0.7Cu0.3/W18O49 photocatalyst exhibits a superior visible-light-driven H2 generation yield of 880 mL min−1 g−1 with excellent stability. The turnover frequency (TOF) value of Ru0.7Cu0.3/W18O49 was found to be 1.44 times higher under visible light irradiation compared to the dark condition, achieving 133.1 min−1. The present study establishes a pioneering approach for the systematic design of highly efficient and durable heterostructure catalysts.
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•Cr, Cu and Ti enhance tribo-catalytic degradation of dyes by BaTiO3 nanoparticles.•Ti promotes tribo-catalytic degradation of concentrated dyes by BaTiO3 nanoparticles.•Electrons ...excited in BaTiO3 are transferred to metallic coatings during friction.•DFT calculations provide theoretical support for the proposed electron transfer.
Recently, tribo-catalysis has emerged as an appealing technology to harvest mechanical energy for environmental remediation. While most investigations have focused on catalyst optimization to enhance tribo-catalytic degradation, here we studied the effects of some metal disks placed on beaker bottoms (named coatings) on the tribo-catalytic degradation by BaTiO3 (BTO) nanoparticles under magnetic stirring. For 20 mg/L Rhodamine B (RhB) solution, Cr, Cu, and Ti coatings improved the kinetic constants of BTO nanoparticles by 3.1, 3.4, 5.2 folds, respectively. Ti coating was further found to result in 99 % degradation in just 3 h for 50 mg/L RhB solution, and elevate the kinetic constants by 19.1 and 16.6 folds for 20 mg/L methyl orange (MO) and 20 mg/L methylene blue (MB) solutions, respectively. EPR, FL and UV–vis spectroscopy verified that modifying vessel bottom with Ti coating enabled BTO nanoparticles to generate more active species. First-principles calculations of the work functions of Cr, Cu, and Ti surfaces, and the energy-band structure of BTO revealed a decreased electron-hole recombination rate due to the transfer of excited electrons to metallic coatings. These results suggest that modifying vessel bottoms with suitable metallic coatings is a simple, eco-friendly and efficient strategy to boost tribo-catalysis for environmental remediation.
In this study, N and P were used to double doping MXene to obtain N,P-MXene with increased layer spacing and structural defects. Schottky junction N,P-MXene/ZnIn2S4 photocatalysts with tight ...interfacial contacts were obtained by in situ growth of flower-like ZnIn2S4 nanosheets. The N,P-MXene interlayer spatial structure facilitates the uniform dispersion of ZnIn2S4 and the exposure of the active site. The formation of the Schottky barrier enables the two closely contacted interfaces to form a carrier transport channel, which accelerates the arrival of the charge carriers on the catalyst surface for REDOX reactions. 50 N,P-MXene/ZIS degraded 86.1 % of CIP and 93.9 % of MO. In addition, after several cycling experiments, it was proved that the photocatalyst had good structure and chemical stability. The photocatalytic mechanism was demonstrated by UPS and radical quenching experiments. N,P-MXene/ZnIn2S4 is not only suitable for pH = 7–11, but also for salt solution wastewater containing higher concentrations of NaCl or KCl. Therefore, the construction of heteroatom doped N,P-MXene/ZnIn2S4 Schottky junction photocatalysts with excellent photocatalytic degradation performance is of profound significance for the treatment of pollutants.
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•N and P elements double doping MXene to obtain N,P-MXene with increased layer spacing and defective structure.•N,P-MXene/ZIS Schottky barrier composite photocatalyst degraded CIP (86.1 %) and MO (93.9 %) with high efficiency.•Schottky barrier promotes the formation of charge carrier transport channels, which is beneficial to the separation of photogenerated electron and hole pairs.
