Transfer Of Photoinduced Carriers Research Articles

Cu/S Co-anchoring junction boosted the photogenerated carrier separation efficiency in g-C3N5 for enhanced H2 evolution

C3N5 is emerging as an important visible light catalyst because of its narrow band gap, nontoxicity and thermal stability. Herein, sulfur-doped g-C3N5 (SCN) was prepared by copolymerization of thioacetamide (TAA) and 3-amino-1,2,4-triazole (3-AT). Then copper nanoparticles (Cu NPs) were anchored onto the SCN framework, resulting in the formation of Cu/SCN. It was found that the average H2 production rate of SCN and Cu/SCN was 0.76 and 1.34 mmol g−1 h−1, which was much higher than that of C3N5, respectively. Acting as a new active spots, sulfur doping effectively reduces the band gap of g-C3N5, and the formation of S-Cu bonds further creates an efficient electron transport pathway. As a result, Cu/SCN possesses a broader visible light absorption spectrum, stronger reduction capability, and greater efficiency in photo-induced carrier separation and transfer. Therefore, this work introduces a novel strategy for design of high efficiency photocatalytic H2 evolution carbon nitride through non-noble metal and sulfur anchoring junction.

Enhanced Photothermal-Assisted Hydrogen Production via a Porous Carbon@MoS2/ZnIn2S4 Type II-S-Scheme Tandem Heterostructure.

MoS2/ZnIn2S4 flower-like heterostructures into porous carbon (PC@MoS2/ZIS) are embedded. This ternary heterostructure demonstrates enhanced light absorption across a broad spectral range from 200 to 2500nm. It features both Type-II and S-scheme dual heterojunction interfaces, which facilitate the generation, separation, and transfer of photoinduced carriers. The PC enveloped by MoS2/ZIS composite microspheres serves as a photothermal source, providing additional energy to the carriers. This process accelerates charge separation and migration, enhancing photothermal-assisted photocatalytic H2 evolution. The optimal H2 evolution rate for PC@MoS2/ZIS reaches an impressive 18.79mmolg-1h-1, with an apparent quantum efficiency of 14.1% at 400nm. This work presents a promising approach for effectively integrating multicomponent heterostructures with photothermal effects, offering innovative strategies for efficient solar energy utilization and conversion.

Modulating Eco-friendly Colloidal AgGaS2 Quantum Dots for Highly Efficient Photodetection and Image Sensing via Direct Growth of Ternary AgInS2 Shell.

Tailoring the optoelectronic characteristics of colloidal quantum dots (QDs) by constructing a core/shell structure offers the potential to achieve high-performing solution-processed photoelectric conversion and information processing applications. In this work, the direct growth of wurtzite ternary AgInS2 (AIS) shell on eco-friendly AgGaS2 (AGS) core QDs is realized, giving rise to broadened visible light absorption, prolonged exciton lifetime and enhanced photoluminescence quantum yield (PLQY). Ultrafast transient absorption spectroscopy demonstrats that the photoinduced carrier separation and transfer kinetics of AGS QDs are significantly optimized following the AIS shell coating. As-synthesized environmentally benign AGS/AIS core/shell QDs are employed to fabricate photodetectors (PDs), showing a remarkable responsivity of 38.4 AW-1 and a detectivity of 2.4×1012 Jones under visible light illumination (405 nm). Moreover, the fabricated QDs-PDs exhibit superior image-sensing capability to record complex patterns with high resolution (160×160 pixels) under visible light illumination at 405 and 532 nm. The findings indicate that the direct growth of multinary narrow-band shell materials on eco-friendly QDs holds great promise to implement future "green", cost-effective and high-performance optoelectronic sensing/imaging systems.

Interface coupling to improve O2 adsorption and accelerate charge separation for boosting photocatalytic performance of ZnO/ZnIn2S4 composite in H2O2 production and environmental remediation

The key to heterogeneous photo-Fenton technology lies in the efficient generation of hydrogen peroxide (H2O2). Herein, a newly-designed ZnO/ZnIn2S4 composite with heterostructure is synthesized. Benefiting from the formation of built-in electric field, the recombination of photoinduced electrons and holes is suppressed and interfacial charge transfer resistance is reduced. Importantly, the embedding of ZnO in ZnIn2S4 can improve the hydrophobicity and create microscopic three-phase interface, thereby boosting the capture capability for O2 and providing the convenience for the occurrence of O2 reduction reaction. More interestingly, the existence of ZnIn2S4 in the ZnO/ZnIn2S4 composite can reduce the Gibbs free energy (ΔG) of key intermediate (OOH*) formation, which will accelerate the generation of H2O2. As a result, the ZnO/ZnIn2S4 composite displays excellent performance in photocatalytic H2O2 production, and the highest yield was about 897.6 μmol/g/h within 60 min under visible light irradiation. The transfer of photoinduced carriers follows the S-scheme type mechanism. The photogenerated holes can be captured by drug residues (i.e., diclofenac sodium) to accelerate H2O2 production, while generated H2O2 can combine with Fe2+ to construct photo-Fenton system for achieving the advanced degradation of diclofenac sodium, which was mainly related to the formation of OH•. Furthermore, generated H2O2 can be applied for performing the inactivation of pathogenic bacteria. In short, current work will provide a valuable reference for future research.

C3N5/TiO2 S-scheme heterojunction film for efficient photocatalytic removal of gatifloxacin

Constructing efficient and recyclable photocatalysts is a promising method to solve antibiotic pollution. Herein, we designed and fabricated C3N5/TiO2 S-scheme heterojunction film on flexible Ti foils through the self-absorbed. The C3N5 nanosheet was tightly anchored on the TiO2 arrays with an intimate TiO2-C3N5 interface. The heterojunction exhibited an excellent photocatalytic performance and the reaction rate constant of photocatalytic degradation gatifloxacin (GAT) over C3N5/TiO2 up to 0.0252 min−1, which was 1.85 folds that of pure TiO2 arrays. The outstanding photocatalytic performance was ascribed to high-efficiency transfer and separation of photoinduced carriers and highly hydrophilic surfaces. The removal rate of GAT under different parameters suggested that the as-prepared C3N5/TiO2 has high adaptability. Moreover, the three possible GAT degradation pathways over C3N5/TiO2 were proposed based on the results of the liquid chromatograph-mass spectrometer (LC-MS) and density functional theory (DFT). Finally, a reasonable S-scheme heterojunction was proposed based on the results of experiments and DFT calculation. This work may help in designing an S-scheme heterojunction for the degradation of antibiotic pollutants.

Photoinduced carrier transfer dynamics in a monolayer MoS2/PbS quantum dots heterostructure

Two-dimensional molybdenum disulfide (MoS2) has been proven to be a candidate in photodetectors, and MoS2/lead sulfide (PbS) quantum dots (QDs) heterostructure has been used to expand the optical response wavelength of MoS2. Time-resolved pump-probe transient absorption measurements are performed to clarify the carrier transfer dynamics in the MoS2/PbS heterostructure. By comparing the carrier dynamics in MoS2 and MoS2/PbS under different pump wavelengths, we found that the excited electrons in PbS QDs can transfer rapidly (<100 fs) to MoS2, inducing its optical response in the near-infrared region, although the pump light energy is lower than the bandgap of MoS2. Besides, interfacial excitons can be formed in the heterostructure, prolonging the lifetime of the excited carriers, which could be beneficial for the extraction of the carriers in devices.

Fabrication of 2D/2D InVO4/BiVO4 Heterojunction with Synergistic Effects for Enhanced Photocatalytic Degradation and Photoelectrochemical Applications

In this work, we report a novel 2D/2D InVO4/BiVO4 heterojunction nanocomposite constructed through a simple hydrothermal approach. The morphological analysis demonstrated that BiVO4 nanoflakes to be anchored on the surface of InVO4 nanosheets. The InVO4/BiVO4 heterojunction nanocomposite displayed increased light absorption promoting their visible light harvesting. The photoactivity of the prepared InVO4/BiVO4 heterojunction was explored for the degradation of tetracycline (TC) under light treatment. InVO4/BiVO4 heterojunction exhibited superior photocatalytic activity than that of bare InVO4 and BiVO4. The as-prepared InVO4/BiVO4 heterojunction photoanodes achieved a higher photocurrent density of 60 μA/cm2 under illumination in 0.5 M Na2SO4 electrolyte. The enhanced photoelectrochemical performance is attributed to the synergistic effect and interface formation between InVO4 and BiVO4 and can effectively promote the charge separation and transfer of photoinduced carriers in heterojunction.

Insight into Fe-O-Bi electron migration channel in MIL-53(Fe)/Bi4O5I2 Z-scheme heterojunction for efficient photocatalytic decontamination

Building a heterojunction is a fascinating option to guarantee sufficient carrier separation and transfer efficiency, but the mechanism of charge migration at the heterojunction interface has not been thoroughly studied. Herein, MIL-53(Fe)/Bi4O5I2 photocatalyst with a Z-scheme heterojunction structure is constructed, which achieves efficient photocatalytic decontamination under solar light. Driven by the newly-built internal electric field (IEF), the formation of Fe-O-Bi electron migration channel allows for rapid separation and transfer of charge carriers at the heterojunction interface, confirmed by the material characterization and density functional theory (DFT) calculation. The narrower band gap and improved visible light response also contribute to the enhanced photocatalytic activity of composite materials. With levofloxacin as the target pollutant, the optimal MIL-53(Fe)/Bi4O5I2 achieves complete removal of pollutant within 150 min, the photocatalysis rate of which is ca. 4.4 and 26.0 times that of pure Bi4O5I2 and MIL-53(Fe), respectively. Simultaneously, the optimal composite material exhibits satisfactory photodegradation of seven fluoroquinolones, and the photocatalysis rates are as follows: lomefloxacin > ciprofloxacin > enrofloxacin > norfloxacin > pefloxacin > levofloxacin > marbofloxacin. DFT calculations reveal a positive relationship between degradation rate and Fukui index (ƒ0) of main carbon atoms in seven fluoroquinolones. This study sheds light on the existence of electron migration channels at Z-scheme heterojunction interface to ensure sufficient photoinduced carrier transfer, and reveals the influence of pollutant structure on photolysis rate.

Decoration of Bi2MoO6 nanosheets with NH2-UiO-66 for boosting visible-light photocatalytic activities

Constructing heterostructured photocatalysts for organic contaminants elimination is promising in the area of environmental purification. For boosting the photocatalytic performance, modulating the heterojunction interface can enhance solar light utilization and facilitate the transporation of photoinduced charge carriers. In this research, octahedral NH2-UiO-66 nanoparticles with large surface area and wide light absorption range were prepared and further employed to in-situ construction of NH2-UiO-66/Bi2MoO6 nanocomposite. The optimized NH2-UiO-66/Bi2MoO6 nanocomposite displays enhanced photocatalytic activities in the elimination of rhodamine B (RhB) and tetracycline (TC). The corresponding degradation rate constant is about 4 and 1.76 times larger than that of individual Bi2MoO6. Combined with the photochemical and electrochemical results, it can be speculated that the higher photocatalytic performance is assigned to the accelerative photoinduced carrier transfer by the formation of well-contacted heterostructured interface. This study provides a theoretical basis for further developing organic–inorganic hybrid catalyst with significant improvement of photocatalytic properties in wastewater treatment.

Enhanced Spin-Polarized Electric Field Modulating p-Band Center on Ni-Doped CdS for Boosting Photocatalytic Hydrogen Evolution.

It is a challenge to regulate charge separation dynamics and redox reaction kinetics at the atomic level to synergistically boost photocatalytic hydrogen (H2) evolution. Herein, a robust Ni-doped CdS (Ni-CdS) photocatalyst is synthesized by incorporating highly dispersed Ni atoms into the CdS lattice in substitution for Cd atoms. Combined characterizations with theoretical analysis indicate that local lattice distortion and S-vacancy of Ni-CdS induced by Ni incorporation lead to an increased dipole moment and enhanced spin-polarized electric field, which promotes the separation and transfer of photoinduced carriers. In this contribution, charge redistribution caused by enhanced internal electric field results in the downshift of the S p-band center, which is conducive to the desorption of intermediate H* for boosting the H2 evolution reaction. Accordingly, the Ni-CdS photocatalyst shows a remarkably improved photocatalytic performance with an H2 evolution rate of 20.28mmolg-1h-1 under visible-light irradiation, which is 5.58 times higher than that of pristine CdS. This work supplied an insightful understanding that the enhanced polarization electric field governs the p-band center for efficient photocatalytic H2 evolution activity.

In-situ construction of Z-scheme 2D/2D g-C3N4/BiOBr heterojunction with enhanced photocatalytic CO2 reduction

A novel series of g-C3N4/BiOBr (CN/BOB) Z-scheme heterojunction catalysts with two-dimensional/two-dimensional (2D/2D) morphology were synthesized by an in-situ hydrolysis method for photocatalytic CO2 reduction. Without adding any sacrificial agents or co-catalysts, the optimal CN/BOB heterostructure exhibits a boosted CO generation rate of 20.1 μmol·g-1·h-1 under the simulated solar light irradiation, severally being 1.7 and 3.7 times that of pristine BiOBr and g-C3N4. The enhanced performance principally benefit from the 2D/2D microstructure and Z-scheme heterojunction of photocatalysts. The intimate contact of 2D/2D morphology signifies more transmission channels and shorter transfer interface distance of photogenerated charges. While relevant characterizations and first-principles calculations jointly demonstrate that the Z-scheme heterojunction could significantly accelerate the spatial separation and transfer of photo-induced carriers, and evidently promote the redox ability of photocatalysts. The research furnishes a novel strategy to construct a promising bismuth oxyhalide based heterojunction catalyst for the application of photocatalytic CO2 reduction.

Facile synthesis of platinum/polypyrrole-carbon black/SnS2 nanocomposite for efficient photocatalytic removal of gemifloxacin under visible light

Development and designing of effective visible light photocatalysts to overcome the drastrous situation of water pollution requires material with excellent charge transferring skills. In this regard, an efficient ternary nanocomposite photocatalyst comprised of SnS2 nanostructure linked with polypyrrole-doped carbon black (PPC) and platinum nanoparticles (Pt NPs) was successfully fabricated. Effective ternary photocatalyst was synthesized by hydrothermal technique followed by ultra-sonication and photo-reduction methodologies. The XRD measurements confirmed the hexagonal phase of SnS2, and the proper formation of nanocomposite. TEM examination revealed Pt NPs of 5–15 nm in size, dense cocoon like layered structure of PPC along with irregular pellets of SnS2. Acquired diffuse reflectance data confirmed the visible light band gap of synthesized nanomaterials. The Pt@PPC/SnS2 photocatalyst showed excellent destructive potential under visible light with 92.40 % removal of antibiotic gemifloxacin (GFX) in 30 minutes, almost 347 % more efficient than bare SnS2, and was found to be ultrafast for the removal of methylene blue (MB) with total elimination of dye just in 10 minutes. The photoluminescence and photocurrent transient analysis revealed enhanced light absorption capability and increased photo-induced carrier transfer with effective separation behavior, together with increased effective surface area of the ternary photocatalyst as evidenced by the BET surface area measurement.

Enhanced photocatalytic detoxification performance of OVs-enriched Co3O4/BiVO4 benefited from S-scheme interfacial charge pairs separation mechanism

Photocatalysts possess great application prospects in the environmental and energy field, and heterojunction photocatalysts can optimize the separation and transfer of photoinduced carriers to achieve high performance photocatalysis. Herein, Co3O4/BiVO4 (CoBVO) heterojunction photocatalysts were prepared in-situ using a one-step hydrothermal method. The impact of heterojunction structure and oxygen vacancies (OVs) on the light absorption range, band structure, and photogenerated carriers separation behavior of BiVO4 were studied by characterizing the photoelectric properties of the material. The results indicate that the concentration of OVs on BiVO4 samples changes due to formation of heterojunctions. Under simulated solar light irradiation, photocatalytic performance of the synthesized catalysts was investigated using Cr(VI) and moxifloxacin as simulated contaminants, photocatalytic reduction rate constant of Cr(VI) on 2CoBVO (molar ratio of Co/Bi is 2%) is 4.4 times of that on the single BiVO4, and the photocatalytic degradation rate constant of moxifloxacin on 2CoBVO is 1.6 times of that on the reference BiVO4. S-scheme interfacial charges separation and enhanced photocatalytic performance mechanism of OVs-enriched Co3O4/BiVO4 heterojunctions were elucidated based on the experimental observations. This work provides ideas for one-step synthesis of bismuth-based composite photocatalysts, which can be applied to the photocatalytic treatment of heavy metals and antibiotics.

Ultrafast photoinduced carrier transfer dynamics in monolayer MoS2/graphene heterostructure

Two-dimensional molybdenum disulfide (MoS2) has been proved to be a good candidate in photodetectors, and MoS2/graphene (MoS2/G) heterostructure has been widely used to expand the optical response wavelength of MoS2. To clarify the carrier transfer dynamics in the MoS2/G heterostructure, time-resolved transient absorption and two-color pump–probe measurements are performed. By comparing the carrier dynamics in MoS2 and MoS2/G under different pump wavelengths, we find that interfacial excitons are formed in the heterostructure, and fast hot carriers transfer (<200 fs) from graphene to MoS2 are observed. The results indicate that the formed heterostructure with graphene can not only expand the optical response wavelength of MoS2 but also improve the response time of the device in the near-infrared region.

Surface sensitization of graphitic carbon nitride with well-defined, organized Pd(II)-directed multiporphyrin array multilayers as ternary photocatalysts for Cr(VI) reduction in aqueous solution

Surface sensitization to a semiconductor is one of the most important strategies to increase the visible light-harvesting ability, photo-induced carrier separation and transfer rate, thus improving the photocatalytic efficiency. Here, ternary nanocomposites are constructed by a Pd(II)-directed layer-by-layer (LBL) coordination bonding of tetrakis(4-aminophenyl)porphyrin (TAPP) on the oxidized graphitic carbon nitride (O-g-C3N4). The nanocomposites of O-g-C3N4@(Pd-TAPP)n as-produced present a porous and ultra-thin lamellar structure with an enhanced absorption ability in the visible light region. As the heterogeneous photocatalyst, O-g-C3N4@(Pd-TAPP)n can reduce the toxic hexavalent Cr(VI) species under visible light irradiation with no need for the sacrificial agent. Further, the photocatalytic activity is enhanced by orders of magnitude higher than that before the surface modification, attributed to the reasons of increased specific surface area, elevated light utilization, meliorative charge separation and transfer rate, as well as the synergistic effect by the multiporphyrin arrays and coordinated Pd(II)/(0) species. In addition to the features of without need of sacrificial agent and irradiation under visible light, the Pd-TAPP multilayer modified nanocomposites have well stability and reusability, resulting in a possibility for the practical application.

Unlocking the Charge‐Migration Mechanism in S‐Scheme Junction for Photoreduction of Diluted CO2 with High Selectivity

AbstractThe rational design of an S‐scheme heterojunctions in hybrid semiconductors to realize separated charge carriers and sufficient redox ability is considered as an attractive way to achieve high photocatalytic activity in diluted CO2 reduction (DCR). An S‐scheme heterojunction formed in the fibrous Ta2O5/Ag2S nanostructures is proposed for improving the photocatalytic performance in DCR under simulated solar irradiation. Benchmark CH4 production rates of 132.3 µmol g−1 are obtained with 93.1% selectivity over optimal catalyst ASTO‐2. The remarkable activity in photocatalytic DCR of Ta2O5/Ag2S is attributed to the unique 0D/1D structure and effective charge separation by the photoinduced strong internal electric field and S‐scheme mechanism. The measurements of in situ X‐ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy, and electron paramagnetic resonance further confirm the photoinduced carrier transfer pathways following the S‐scheme mechanism. This research can provide a new strategy for designing the S‐scheme heterojunctions to improve the photocatalytic performance of diluted CO2 conversion.

Photo-induced surface oxygen vacancy in hierarchical nanoarchitectonics g-C3N4/BiOCOOH to boost photocatalytic CO2 reduction

Photocatalytic CO2 conversion into chemical production and valuable solar fuel has been regarded as a prospective strategy for tackling with the issue of the global warming and energy crisis. A superior photocatalytic system employing heterojunction or oxygen vacancy (OVs) can facilitate efficient charge separation and transfer carriers. In this work, well-designed g-C3N4/BiOCOOH heterojunction microflowers assembly incorporated with abundant oxygen vacancy have been successfully synthesized via a mild photo irradiation treatment method. The BiOCOOH coupled with different amounts of g-C3N4 has an obviously impact on photocatalytic CO2 reduction into CO and CH4. Intriguingly, the as-obtained photo-induced oxygen vacancy g-C3N4/BiOCOOH-10 (CNB-10) show further enhanced CO yield towards photocatalytic CO2 reduction compared with pristine g-C3N4/BiOCOOH. Based on comprehensive characterization, the photo induced plenty of OVs in g-C3N4/BiOCOOH via UV light irradiation for 10 min could promote CO2 adsorption capacity as well as separation and transfer of photo-induced carriers, and significantly boost catalytic activity toward CO2 photoreduction. The elevated CO2 photoreduction activity of CNB-10 could be ascribed to the synergic effect of oxygen vacancy and S-scheme heterojunction structure on efficient carrier utilization and visible light absorption. This work can offer new perspectives and guidelines for the rational design of catalysts with satisfactory performance of CO2 reduction.

Rapid elimination of thiamethoxam insecticide under visible light using novel Au nanoparticles/CdSe/WO3 ternary nanocomposite

In this study, we have created a unique ternary photocatalyst using WO3 nanostructures in conjunction with CdSe and gold nanoparticles (Au NPs), which exhibits remarkable efficacy in purifying contaminated water under visible light. The Au, CdSe, and WO3 assembled ternary photocatalyst was synthesized through ultrasonication followed by a photoreduction process. The X-ray diffraction (XRD) analysis confirmed the presence of monoclinic WO3, hexagonal CdSe, and Au NPs in the ternary photocatalyst. Structural analysis and elemental composition were further substantiated through X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) studies. Transmission electron microscopy (TEM) examinations revealed irregularly shaped Au NPs (5–15 nm), CdSe, and WO3 particles. Diffuse reflectance studies demonstrated a reduction in the band gap energy of the Au@CdSe/WO3 nanostructures. The Au@CdSe/WO3 ternary photocatalyst exhibited remarkable efficiency in the photocatalytic degradation of thiamethoxam (TXM) insecticide and methylene blue (MB) dye under visible light. It achieved an impressive 94.13 % removal efficiency for TXM in just 40 min, which was ∼2.04 more efficient than undoped WO3. Additionally, the Au@CdSe/WO3 nanostructures successfully decolorized MB dye under visible light within 14 min. This exceptional photocatalytic performance can be attributed to the increased surface area, enhanced light absorption capacity, and improved photo-induced carrier transfer with efficient separation behavior, as evidenced by photoluminescence and photocurrent transient analyses.

MOF-Derived Hollow Spheres of MIL-100(Fe)-NH2(20) with Well-Developed Hierarchical Mesoporous and Uniform Distribution of Fe and N Active Phases for the Photocatalytic Removal of Organic Dyes.

For the first time, MIL-100(Fe)-derived microspheres with a hollow structure were perfectly constructed and used as a photocatalyst to decompose organic dyes under visible light irradiation. The prepared MIL-100(Fe)-NH2(20) could boost the separation, migration, and transfer of photoinduced carriers effectively, together with efficient photocatalytic performance. In simulated sunlight, the MIL-100(Fe)-NH2(20) exhibits the best degradation efficiency as well as excellent reusability and stability, and the degradation rate for rhodamine B (RhB) can be more than 99.5% within 80 minutes. Structural analysis proves that the porous MIL-100(Fe)-NH2(20) catalyst reaps an amazing hollow structure, large specific surface areas (2784.9 m2·g-1), and uniform distribution of Fe and N active phases. Besides, the enhanced visible light response and lower recombination rate of e--h+ pairs are both confirmed, and the band gap is significantly reduced to 2.53 eV. Finally, the photocatalytic mechanism and the possible degradation pathway were suggested. Owing to the enhanced photocatalytic activity, good tolerance to pH and water quality, and excellent stability, the MIL-100(Fe)-NH2(20) catalyst can be potentially used in a wide range of dye wastewater purifications.

Photogenerated Defect‐Transit Dual S‐Scheme Charge Separation for Highly Efficient Hydrogen Production

AbstractThe rational design of a step‐scheme (S‐scheme) heterojunctions in hybrid semiconductors by avoiding unwanted charge transport paths is considered as an attractive way to achieve high photocatalytic activity in hydrogen evolution reaction (HER). Here, a dual S‐scheme heterojunction formed in the lychee‐shaped W18O49/CdWO4/CdS nanostructures is proposed for improving the photocatalytic performance in HER under visible light irradiation. The remarkable activity in photocatalytic HER of W18O49/CdWO4/CdS is attributed to the unique structure and effective charge separation by the photoinduced defect‐transit dual S‐scheme mechanism and strong internal electric field. The measurements of X‐ray photoelectron spectroscopy (XPS), femtosecond transient absorption (fs‐TA) spectroscopy, and electron paramagnetic resonance (EPR) further confirm the photoinduced carrier transfer pathways following the dual S‐scheme mechanism. This research can provide a new strategy for designing the dual S‐scheme heterojunctions to improve photocatalytic performance through the defect band structure engineering.