Separation Of Photogenerated Charge Carriers Research Articles

Unraveling the Nature of Local Field Distortion-Induced Dual Electron-Trapping Centers for Efficient Photocatalytic Fuel Evolution

Active electron-trapping centers play significant roles in photocatalysis. Herein, we synergize local field distortion and defects in nanocrystals to produce dual electron-trapping centers and unravel the nature of aluminum doping in porous ZnO with tunable amounts of heteroatoms and oxygen vacancies. The introduced Al atoms in the structural domain induce local field distortion and trigger the movement of Zn2+ from a singlet low spin state to a stable triplet state, resulting in the generation of free carriers trapping centers and optimized electronic energy band structure. Dual active electron-trapping centers of heteroatoms and oxygen vacancies promote the Separation of photo-generated charge carriers and reduce the adsorption energies of H* species. Furthermore, the d-band center of Al-doped ZnO with oxygen vacancies shifts to a higher energy position, thus promoting the adsorption and desorption of hydrogen intermediates and exhibiting 4-fold the photocatalytic H2 efficiency of pristine ZnO. This study provides new insights into the rational design of highly efficient oxide-based photocatalysts toward sustainable solar fuel evolution.

Fabrication of ternary Bi2S3/BiVO4/g-C3N4 composite material for enhanced photocatalytic degradation of antibiotics

Antibiotic contaminants are known to pose a serious threat to the human health and environment, thus a great deal of effort has been made to develop destruction technologies for antibiotic treatment in the water environment. Photocatalytic oxidation technology is regarded as one of the most promising strategies for decomposing antibiotics from water. In this work, ternary Bi2S3/BiVO4/g-C3N4 composite material is dexterously designed and synthesized to obtain the enhanced photocatalytic performance for tetracycline (TC) degradation via a facile strategy. Therein, the optimal Bi2S3/BiVO4/g-C3N4 material showed the excellent degradation efficiency under visible light irradiation in comparison to the nude g-C3N4 and BiVO4/g-C3N4 photocatalysts, and it can continuously degrade the TC pollutant in 90 min and achieve a degradation percentage of 80.7 %. The designed materials can not only intensify photo-absorption efficiency of g-C3N4 material, but also improve its separation and transfer efficiency of photo-generated charge carriers, which is attributed to the incorporation of BiVO4 and Bi2S3 materials. The active species trapping experiments verified that the superoxide radicals (•O2−) is the main active species, and holes (h+) also played an important role in the Bi2S3/BiVO4/g-C3N4 system. Furthermore, the photoelectrochemical measurement (PEC) clearly demonstrated that the incorporation of BiVO4 and Bi2S3 materials could accelerate the separation and transfer of photo-generated electron and hole pairs. As expected, our present work could spark new inspirations to further develop the efficient photocatalysts for solar energy conversion.

Ultrafast electron transfer at the In2O3/Nb2O5 S-scheme interface for CO2 photoreduction

Constructing S-scheme heterojunctions proves proficient in achieving the spatial separation of potent photogenerated charge carriers for their participation in photoreactions. Nonetheless, the restricted contact areas between two phases within S-scheme heterostructures lead to inefficient interfacial charge transport, resulting in low photocatalytic efficiency from a kinetic perspective. Here, In2O3/Nb2O5 S-scheme heterojunctions are fabricated through a straightforward one-step electrospinning technique, enabling intimate contact between the two phases and thereby fostering ultrafast interfacial electron transfer (<10 ps), as analyzed via femtosecond transient absorption spectroscopy. As a result, powerful photo-electrons and holes accumulate in the Nb2O5 conduction band and In2O3 valence band, respectively, exhibiting extended long lifetimes and facilitating their involvement in subsequent photoreactions. Combined with the efficient chemisorption and activation of stable CO2 on the Nb2O5, the resulting In2O3/Nb2O5 hybrid nanofibers demonstrate improved photocatalytic performance for CO2 conversion.

Enhanced Photocatalytic Hydrogen Evolution of In2S3 by Decorating In2O3 with Rich Oxygen Vacancies.

The hydrogen (H2) evolution rates of photocatalysts suffer from weak oxidation and reduction ability and low photogenerated charge carrier separation efficiency. Herein, by combining band-gap structure optimization and vacancy modulation through a one-step hydrothermal method, In2O3 containing oxygen vacancy (Ov/In2O3) is simply introduced into In2S3 to promote photocatalytic hydrogen evolution. Specifically, the change in the sulfur source ratio can induce the coexistence of Ov/In2O3 and In2S3 in a high-temperature hydrothermal process. Under light irradiation, In2S3@Ov/In2O3-0.1 nanosheets hold a remarkable average H2 evolution rate up to 4.04 mmol g-1 h-1, which is 32.14, 11.91, and 2.25-fold better than those of pristine In2S3, In2S3@Ov/In2O3-0.02, and In2S3@Ov/In2O3-0.25 nanosheets, respectively. The ultraviolet-visible (UV-vis) diffuse reflectance and photoluminescence (PL) spectra reveal that the formation of Ov/In2O3 in In2S3 optimizes the band-gap structure and accelerates the migration of the photogenerated charge carrier of In2S3@Ov/In2O3-x nanosheets, respectively. Both the enhancement of oxidation and reduction ability and photogenerated charge carrier separation ability are responsible for the remarkable improvement in photocatalytic H2 evolution performance. This work provides a new strategy to prepare a composite of metal sulfide and metal oxide through a one-step hydrothermal method.

Advancing photocatalytic activity through a green route: Bismuth ferrite@molybdenum trioxide heterostructure for sustainable water treatment

Photocatalysis has become increasingly pervasive in the chemical industry, profoundly impacting operational costs. However, an ideal photocatalyst must possess characteristics such as excellent reactivity, high selectivity, prolonged stability, low toxicity, and cost-effectiveness. Moreover, it should facilitate the efficient separation of photo-generated charge carriers, thereby minimizing recombination rates. In pursuit of advancing photocatalytic activity for sustainable water treatment, this investigation focused on synthesizing a groundbreaking photocatalyst, the Bismuth Ferrite@Molybdenum trioxide heterostructure, using an eco-friendly green chemistry technique with pomegranate extract. This approach aligns with the goal of environmental sustainability and represents a novel contribution to the field. Employing a comprehensive approach, advanced characterization techniques such as XRD, SEM, FT-IR, and UV–Vis were applied to analyze the material's structural, morphological, and optical properties. According to the characterization results, the heterostructure demonstrates superior photocatalytic efficiency, heightened crystallinity, and reduced recombination rates during dye degradation for water treatment compared to both individual photocatalysts. Notably, the composite catalyst exhibits a synergistic impact, outperforming individual BiFeO3 and MoO3 photocatalysts. SEM observations confirm the successful integration of rod-like MoO3 and cylindrical BiFeO3 morphologies, highlighting the strategic combination achieved through the green chemistry route. Furthermore, UV–Vis spectroscopy reveals key optical parameters, emphasizing a narrow bandgap energy of 2.74 eV with a high refractive index of 2.43 eV. The exceptional efficacy of the heterostructure in degrading dyes within the visible spectrum, surpassing expectations within a 4-hour timeframe, highlights its efficiency and precision. Remarkably, achieved degradation rates for Rhodamine B dye (98 %), Methyl Blue (96 %), and Methyl Orange dye (95 %) highlights the promising role of proposed photocatalytic system in effectively addressing water pollutant challenges.

Construction of carbon and nitride double vacancy defects on ultrathin porous g-C3N4 nanosheets assisted by freeze-drying for enhanced photocatalysis

Graphitic carbon nitride based photocatalysts have been found extensive application in the degradation of antibiotics and organic pollutants. However, the insufficient of surface active sites and the low efficiency of photogenerated charge carriers separation hinder the development. Herein, ultrathin porous polymer carbon nitride nanosheets (PCNS-F) with carbon and nitride double vacancy defects were successfully fabricated. The facile freeze-drying step, following solvent-thermal treatment and preceding the thermal etching process, stands as a critical step for triggering vacancy generation and adjusting the carbon/nitride ratio. The optimized PCNS-F photocatalyst exhibits an ultrathin structure featuring a substantial abundance of defects in a porous state, resulting in exceptional structural characteristics (183.3 m² g-1, 0.84 cm³ g-1). Surface defect sites increase, and the efficient separation and transfer of photo-generated charge carriers are promoted with the introduction of a suitable vacancy density. PCNS-F demonstrated outstanding photocatalytic degradation performances for tetracycline (81.7 %) and methylene blue (97.7 %) under visible light irradiation for 2 h, which are 10 and 7.2 times higher than those of bulk g-C3N4. The active species of ∙O2- was confirmed to play a major role in the photodegradation process. This work provides a mild approach for engineering carbon and nitride double vacancy defects on g-C3N4 nanosheets, accompanied by tuning carbon/nitride ratio, to effectively eliminate pollutants and cleanse the environment.’

Dual Channel H2O2 Photosynthesis in Pure Water over S-Scheme Heterojunction Cs3PMo12/CC Boosted by Proton and Electron Reservoirs.

Dual channel photo-driven H2O2 production in pure water on small-scale on-site setups is a promising strategy to provide low-concentrated H2O2 whenever needed. This process suffers, however, strongly from the fast recombination of photo-generated charge carriers and the sluggish oxidation process. Here, insoluble Keggin-type cesium phosphomolybdate Cs3PMo12O40 (abbreviated to Cs3PMo12) is introduced to carbonized cellulose (CC) to construct S-scheme heterojunction Cs3PMo12/CC. Dual channel H2O2 photosynthesis from both H2O oxidation and O2 reduction in pure water has been thus achieved with the production rate of 20.1mmolL-1gcat. -1h-1, apparent quantum yield (AQY) of 2.1% and solar-to-chemical conversion (SCC) efficiency of 0.050%. H2O2 accumulative concentration reaches 4.9mmol L-1. This high photocatalytic activity is guaranteed by unique features of Cs3PMo12/CC, namely, S-scheme heterojunction, electron reservoir, and proton reservoir. The former two enhance the separation of photo-generated charge carriers, while the latter speeds up the torpid oxidation process. In situ experiments reveal that H2O2 is formed via successive single-electron transfer in both channels. In real practice, exposing the reaction system under natural sunlight outdoors successfully results in 0.24mmol L-1 H2O2. This work provides a key practical strategy for designing photocatalysts in modulating redox half-reactions in photosynthesis.

Enhanced oxygen evolution of a new copper-based metal-organic framework through the construction of a heterogeneous structure with bismuth oxyiodide

Herein, a newly developed MOF, Cu-based on 2-amino terephthalic acid (CuATPA) is successfully prepared and utilized as a photoanode material. To achieve high-efficiency electron/hole separation and rapid catalytic kinetics, a heterojunction architecture is designed by combining CuATPA with BiOI. Scanning electron microscopy images reveal the formation of CuATPA nanoplates within the structures of BiOI nanoflakes. Electrochemical characterization demonstrates the excellent photoelectrocatalytic performance of the CuATPA-BiOI nanocomposite. Linear sweep voltammetry reveals a reduced overpotential value for the CuATPA-BiOI nanocomposite, indicating enhanced catalytic activity. Moreover, the CuATPA-BiOI photoanode displays a photo-voltage of 0.43 V compared to 0.23 and 0.24 V for the CuATPA and BiOI photoanodes, respectively, indicating a deeper band bending. The improved photoelectrochemical performance of the nanocomposite is attributed to efficient separation and transfer of photo-generated charge carriers, as evidenced by higher charge density extracted from the Mott-Schottky plot and smaller semicircle radius in the Nyquist plot.

Enhanced photocatalytic H2 evolution over conjugated polymer/Au@TiO2 ternary heterojunction under visible light: Enriched photons input from polymers

Exploring efficient and stable TiO2-based photocatalysts for visible-light H2 evolution remains a great challenge. Here, a novel ternary heterojunction (THSO/Au@TiO2) was successfully synthesized by a facile in-situ polymerization strategy, which showed highly enhanced photocatalytic activity towards H2 evolution under visible light. The optimized THSO/Au@TiO2-26 exhibited an excellent photocatalytic performance to H2 evolution (7504 μmol/g/h), which was 16.31, 416.89 and 1.81 times higher than that of THSO, TiO2 and THSO/TiO2 photocatalysts, respectively. This excellent performance should be attributed to the excellent visible light absorption ability of the polymer THSO, and the local surface plasmonic resonance effect of Au nanoparticles (Au NPs), promoting separation and transfer of photo-generated charge carriers. This work presents new insights for the design of efficient and rational TiO2-based photocatalytic systems to enhance photocatalytic performance towards H2 evolution under visible light.

Enhanced photocatalytic performance of MXene-Modified cation-exchanged CoFe-LDH/CoFeCrO4 heterostructure for Antibiotic degradation and hydrogen production through synergistic charge dynamics

Systemizing an effective charge-transfer channel across a junction interface replete with ample active sites for enhancing the photocatalytic activity of semiconducting materials presents a formidable challenge. Here, we present a novel approach based on an in situ hydrothermal method for synthesizing CoFe-Layered Double Hydroxide (LDH)/CoFeCrO4 heterojunction materials that were partially derived from CoFe-LDH. These materials synergistically interact with Ti3C2 MXene nanosheets facilitating multi-interface interactions. Indeed, the highest tetracycline hydrochloride degradation rate of nearly 92% in 2 h was achieved because of the intense synergy between the CoFe-LDH/CoFeCrO4 heterojunction material optimized with 7.5 wt% of MXene nanosheets (CMC-7.5). This degradation performance was 3.1 times greater than that of the original CoFe-LDH. Further, CMC-7.5 produces the highest H2 gas of 458.79 μmol h−1g−1 from a photocatalytic water splitting reaction. The formation of a Schottky energy barrier between the partially derived CoFe-LDH/CoFeCrO4 unit and MXene promoted the fast transfer of photogenerated electrons from CoFe-LDH/CoFeCrO4 to the surface of MXene, thereby providing a plethora of active sites for photocatalytic reactions. Photoelectrochemical assessments using transient and linear sweep voltammetry along with electrochemical impedance spectroscopy confirmed efficient charge carrier transfer. Moreover, the optimized CMC-7.5 photoelectrode has a superior integral area and exhibited excellent stability over 100 cycles. Finally, the study outlines the construction of several advanced materials with multi-interface heterojunctions involving cation-exchanged LDH derivatives with high photogenerated charge carrier separation efficiency and minimal interfacial migration resistance to serve as stability benchmarks for practical applications.

Microstructure driven charge carrier separation in superior thin g-C3N4 nanosheets towards enhanced photocatalytic activities

The performance of graphic carbon nitride (g-C3N4) depended strongly on solar energy harvesting and photogenerated charge carrier separation and transfer. Defect engineering (local component and crystallinity adjustment) helps g-C3N4 to improve photocatalytic activity. In this paper, superior thin g-C3N4 nanosheets with typical microstructures were created using a two-step thermal polymerization at high temperature by adjusting precursors. g-C3N4 nanosheets obtained using melamine revealed fine crystallinity compared with that created using dicyandiamide even though related flat microstructure observed for two samples. In contrast, a wrinkled microstructure with self-assembled amorphous/crystalline junctions was created by urea. Interestingly, the wrinkled one revealed the fastest degradation for RhB which was degraded over within 5 min and a high H2 generation rate of 3473 μmol·g−1·h−1 compared with other samples. This performance is ascribed that wrinkle ultra-thin g-C3N4 nanosheets with amorphous-crystalline junctions significantly improved light harvesting ability and photogenerated carrier separation and transport efficiencies. Furthermore, almost no H2 was generated using molten-salt (NaCl and KCl) assisted porous g-C3N4 nanosheets. These results suggest that increased active sites generated by defect engineering were crucial for the photocatalytic performance of g-C3N4. The detailed discussion on microstructure formation provides an important platform for the construction of highly efficient g-C3N4 based photocatalysts.

Construction of S-scheme BiOCl/layered bimetallic oxide heterojunction for enhanced photocatalytic degradation of bisphenol A

Constructing heterogeneous photocatalysts to enhance the visible light absorption and photo-generated charge carrier separation for efficient degradation of organic pollutants in water samples remained a significant challenge. An S-scheme BiOCl/ZnCrZr-layered bimetallic oxide (LBMO) heterojunction was constructed by depositing BiOCl nanoparticles on ZnCrZr-LBMO. The characterization of material samples were by XRD, SEM, TEM, XPS, FTIR, UV–Vis-DRS, transient photocurrent response, and electrochemical impedance spectroscopy. The photocatalytic efficiency of BiOCl/ZnCrZr-LBMO heterojunction was obviously improved, about 3.95 and 1.68 folds higher than that of pristine BiOCl and ZnCrZr-LBMO, respectively. The fast separation and migration and the prolonged lifetime of photo-generated carriers in the BiOCl/ZnCrZr-LBMO heterojunction were validated by photoelectrochemical tests. The influence factors, versatility, and reusability of the heterojunction were also evaluated. Free radical scavenging test and ESR experiment revealed that ·O2– and h+ active radicals were the dominant active radicals in the BPA degradation. Additionally, BPA degradation intermediates were detected by LC-MS, and the possible degradation pathway of BPA was deduced using density functional theory. This novel S-scheme model heterojunction was expected to provide new ideas for the study of the photocatalytic mechanism and the BPA removal.

Efficient photocatalytic chloride dehalogenation by planar conjugated microporous polymers with enhanced charge separation and transport

Modulation of charge separation and transport in conjugated porous polymer photocatalysts by altering molecular planarity to better address the challenges of the chloride dehalogenation reaction.

Synergistic effect of Ag@CN with BiVO4 in a unique Z-type heterojunction for enhancing photoelectrochemical water splitting performance.

In the realm of photoelectrochemical technology, the enhancement of photogenerated charge carrier separation is pivotal for the advancement of energy conversion performance. Carbon nitride (CN) is established as a photocatalytic material with significant potential and exhibits unique advantages in addressing the issue of rapid recombination of photogenerated carriers. This study utilized an efficient in situ doping method that combined Mo,W-doped BiVO4 (Mo,W:BVO) with silver-loaded CN (Ag@CN), yielding an all-solid-state Mo,W:BVO/Ag@CN heterostructure that effectively augments the separation efficiency of electron-hole pairs. Through the annealing process, Ag@CN was uniformly coated within the Mo,W:BVO thin film, significantly enlarging the interface contact area to enhance visible light absorption and photogenerated carrier movement. The results of the photoelectrochemical tests showed that the Mo,W:BVO/Ag@CN heterostructure had the highest photocurrent and charge transfer efficiency, which were 6.4 times and 3.6 times higher respectively than those of the unmodified Mo,W:BVO. Our research elucidates the interactions within all-solid-state Z-scheme heterojunctions, outlining strategic approaches for crafting innovative and superior photocatalytic systems.

Self-induced electron attraction center formation with pyrophosphorylation strategy for photocatalytic hydrogen evolution.

An integral approach towards augmenting the performance of photocatalytic hydrogen production lies in the induction of charge transfer mediators within the material matrix itself, thereby facilitating swift and efficient charge transfer processes. Here, CoTiO3 is induced to grow its electronic attraction center, CoP3, through a high-temperature phosphatization strategy. CoP3 acts as the active reduction site for the hydrogen evolution reaction and enhances the photocatalytic performance of the pristine catalyst. Compared with pure CoTiO3, the PCTO7 hybrid catalyst with the electronic attraction center CoP3 exhibits a superior photocatalytic performance and good stability. Experimental results show that the hydrogen evolution performance of the PCTO7 hybrid catalyst reaches 56.52 μmol, which is 78 times higher than that of the single catalyst CoTiO3 (0.72 μmol). These results demonstrate that the hybrid catalyst with the self-induced electronic attraction center has a higher light absorption capacity, faster charge carrier dynamics and improved photogenerated charge carrier separation and transfer than pure CoTiO3, resulting in excellent redox capability. DFT calculations provide evidence supporting the topological metal properties of CoP3 as the electron sink center. This study provides a feasible approach for enhancing the photocatalytic performance of a pristine catalyst employing a high-temperature phosphatization-induced electron sink center.

Morphology-controlled fabrication of Nb5+ doped SrTiO3 for promoting photocatalytic reduction of Cr(VI)

To achieve improved photocatalytic activity of Nb5+ doped SrTiO3 (Nb-SrTiO3), Nb-SrTiO3 nanomaterials with different morphologies were prepared via a one-step solvothermal method in ethylene glycol (EG)-H2O mixed solvents. The photocatalytic activities of the as-prepared Nb-SrTiO3 samples were evaluated by the reduction of Cr(VI) under xenon lamp irradiation. The effects of the ratio of VEG/VH2O on the morphology, optical and electronic properties, and photocatalytic activity of Nb-SrTiO3 were investigated. The results indicated that Nb-SrTiO3 with different shapes, including block, sphere, and flower-like structure, could be prepared by controlling the ratio of VEG/VH2O. The sphere-shaped Nb-SrTiO3-3 obtained with the ratio of VEG/VH2O being 4 exhibited stronger light absorption, more efficient separation and transfer of photo-generated charge carriers, and superior photocatalytic activity. Moreover, Nb-SrTiO3-3 can catalyze the reduction of almost 100 % Cr(VI) in the diluted Cr(VI)-containing passivation solution after light irradiation for 25 min, so it holds promise in Cr(VI) wastewater treatment.

Pollution-free interface of 2D-MoS2/1D-CuO vdWs heterojunction for high-performance photodetector

Van der Waals heterostructures provide a new opportunity for constructing new structures and improving the performance of electronic and optoelectronic devices. However, the existing methods of constructing heterojunctions are still faced with problems such as impurity introduction, or complex preparation process and limited scope of application. Herein, a physisorption method is proposed to composite CuO nanorods on the surface of MoS2 nanosheets. CuO nanorods and MoS2 form type-Ⅱ heterojunctions, which promotes the separation and transport of photo-generated charge carriers. More importantly, compared with the transfer and coating methods, the physical adsorption method avoids the introduction of auxiliary materials during the whole process of constructing the heterojunction, and therefore effectively reduces the damage and pollution at the interface. The optimized MoS2/CuO heterojunction photodetector achieves a high photoresponsivity of ∼680.1 A W−1 and a fast response speed of ∼29 μs. The results demonstrate that the physisorption method provides a feasible approach to realize high performance photodetectors with pollution-free interfaces, and it can also be extended to the development of other low-dimensional hybrid heterojunction electronic and optoelectronic devices.

Modulation of internal electric field in S-scheme heterojunction towards efficient photocatalytic CO2 conversion

The internal electric field (IEF) inherent within a composite photocatalyst plays a pivotal role in orchestrating the photogenerated charge carrier separation. Consequently, achieving precise regulation of the IEF emerges as the keystone for optimizing photocatalytic performance. Herein, we present a demonstrative study centered around the deliberate manipulation of the IEF within a g-C3N4/In2S3 step-scheme (S-scheme) heterojunction. This manipulation is deftly accomplished through the introduction of sulfur doping (S-doping) into the g-C3N4. Employing advanced techniques such as Kelvin probe force microscopy and density functional theory calculations, we substantiate that S-doping precipitates a reinforcement in IEF existing between g-C3N4 and In2S3. The soundness of this proposition is fortified through in situ X-ray photoelectron spectroscopy, which unveils a pronounced augmentation in the accumulation of photogenerated electrons on the surface of g-C3N4 subsequent to S-doping. This empirically substantiates the enhanced charge carrier dynamics made possible by the manipulation of the IEF within S-scheme heterojunction.

Realizing high-performance glucose sensing in sweat: Synergistic use of nickel oxide nanosheets as photoelectrodes and the masking effect of Mo-POM for photoelectrochemical detection

The detection of blood glucose plays a crucial role in clinical practice, and the innovative use of sweat as a substitute for blood has brought significant practical value in the detection of blood glucose. However, lactic acid (LA) has been found to be the main interfering substance on the detection of glucose in sweat. In this study, a photoelectrochemical sensing system was constructed by using NiO nanosheets as photosensitive materials and molybdenum-based polyoxometalate clusters (Mo-POM) as masking agents. Mo-POM, an ideal electron-capturing agent, effectively promoted the spatial separation of photo-generated charge carriers in NiO nanosheets, thereby enhancing the oxidation rate of glucose on the valence band of NiO and significantly improving the detection sensitivity. Mo-POM also exhibited the characteristics of an electron sponge, facilitating fast and reversible multi-electron transfer reactions and effectively masking certain redox substances, especially lactic acid, thus greatly enhancing the selectivity of the glucose sensor. The photoelectrochemical (PEC) sensor constructed using Mo-POM has excellent sensing capability with high sensitivity to detect glucose at a minimum concentration of 1 nM. The detection limit of the sensor is 0.33 nM (S/N = 3). This sensor can be reliably applied to the detection of glucose in sweat and the accuracy of the results was verified by gas chromatography-mass spectrometry.

W18O49/crystalline g-C3N4 layered heterostructures with full solar energy harvesting towards efficient H2O2 generation and NO conversion

The photocatalytic performance of graphitic carbon nitride (g-C3N4) heterostructures related to the charge carrier separation and transport efficiency is often governed by the interfaces. Herein, in-situ growth of W18O49 nanobelts is attained on amorphous and crystalline g-C3N4 nanosheets to study the effects of the interfaces on photocatalytic oxidation activities. The horizontal growth of W18O49 on g-C3N4 nanosheets is the key in formation of two dimensional (2D)/2D W18O49/g-C3N4 heterostructures. The growth of W18O49 nanobelts on crystalline g-C3N4 nanosheets shows well-developed interfaces (sample W18O49-CCN) in comparison with heterostructures constructed using amorphous g-C3N4 base (sample W18O49-ACN). Characterizations on the structure, components, and properties of the samples demonstrate that these heterostructures reveal extended photo-absorption in visible to near infrared region, with sample W18O49-CCN showing much higher photogenerated charge carrier separation and transport efficiency. A H2O2 evolution rate of 5550 µMg−1h−1 is observed for sample W18O49-CCN under full solar-spectrum illumination (and 398 µMg−1h−1 observed for pristine crystalline g-C3N4), which is ∼ 2.4 times of that of sample W18O49-ACN prepared using amorphous g-C3N4. In addition, a NO removal rate of 72.1% is observed for sample W18O49-CCN with a NO2 selectivity of 6.2%. These results provide inspiration for construction of g-C3N4 homojunctions for practical photo-redox reaction applications.