Photocatalytic Process Research Articles

Photocatalytic Upcyclingof Plastic Waste into Syngas by ZnS/Ga2O3 Z-scheme Heterojunction.

The photocatalytic conversion of plastic waste into value-added products using solar energy presents a promising approach for promoting environmental sustainability. Nonetheless, the emission of CO2 during the conventional photocatalytic degradation process remains a major hurdle that impedes its further development. In this study, we propose an efficient photocatalytic conversion of polyethylene plastic into syngas (CO + H2 mixtures) by using a ZnS/Ga2O3 Z-scheme heterojunction photocatalyst. It is found that the strong redox capability of photogenerated holes and electrons in the Z-scheme heterojunction photocatalyst can promote the oxidative depolymerization of PE plastic, concurrently enabling the efficient reduction of the intermediate product CO2 into syngas. Furthermore, this system also demonstrates applicability in the conversion and upcycling of other polyolefin plastics including polypropylene and polyvinyl chloride. Our findings highlight the potential of polyolefin plastics photoreforming for the production of syngas under environmentally benign conditions.

Exploring the Mechanism for the Photocatalytic Degradation of Oxytetracycline in Water using TiO2 and Supplementary Oxidants

The persistent presence of antibiotics in wastewater, exemplified by oxytetracycline (OTC), poses environmental risks, necessitating robust removal strategies. This study investigates the effectiveness of photocatalysis utilizing TiO2 (P25) treated at various temperatures, combined with different oxidants such as hydrogen peroxide (H2O2), potassium peroxydisulfate (PDS), potassium peroxomonosulfate (PMS) under diverse experimental conditions. The research systematically explores the impact of temperature, pH, and oxidant concentration on the efficiency of OTC degradation. Our findings reveal that the combination of P25/500, PDS, UV irradiation, and stirring demonstrates superior OTC degradation, surpassing 99% efficiency after 180 min. Optimal pH conditions are identified, emphasizing the importance of balancing acidity for enhanced performance. The study also provides insights into the optimal PDS concentration, indicating a threshold beyond which further increases yield diminishing returns. Mechanistic understanding is enhanced through scavenger experiments, elucidating the pivotal role of reactive oxygen species, particularly O2•−, in the photocatalytic process. This research offers a practical framework for TiO2-based photocatalysis in wastewater treatment, emphasizing tailored conditions for efficient antibiotic removal. The outcomes contribute valuable insights to the development of sustainable wastewater treatment protocols targeting antibiotic pollutants.

Rapid Degradation of Dye Effluents with A SnS Catalyst: A Sustainable Approach Using Natural Light Under Ambient Conditions.

Dye degradation presents a persistent challenge in addressing water pollution. While several methods, including adsorption, biodegradation, and advanced oxidation processes, have been extensively explored, photocatalysis remains one of the most effective techniques. Conventional photocatalytic dye degradation processes often rely on expensive light sources and are time-intensive. Herein, we synthesized a SnS catalyst by the solvated metal atom dispersion (SMAD) method, using Sn foil and sulfur powder. The catalyst exhibited remarkable performance, achieving complete degradation of methylene blue within 2 minutes under ambient room light, without the need for any external light source. Similar degradation efficiency was achieved for methyl orange. To evaluate the role of light for the degradation, control experiments were conducted in the dark using methylene blue as a model dye. Although the degradation rate was slightly reduced, the catalyst still facilitated dye degradation in the absence of light. Additionally, the catalytic performance was tested with four other dyes under natural light, all of which yielded promising results, demonstrating the versatility and effectiveness of the SnS catalyst in dye degradation. This work highlights the potential of the SnS catalyst for efficient and rapid dye degradation under both light and dark conditions, offering an energy-efficient solution for wastewater treatment.

Hydroxyl Radical Mediated Heterogeneous Photocatalytic Baeyer–Villiger Oxidation over Covalent Triazine/Heptazine‐Based Frameworks

AbstractThe Baeyer–Villiger (B–V) oxidation of ketones to the corresponding lactones/esters is a classic and essential reaction in the chemical industry. However, this oxidation process has not yet been achieved in ambient conditions with the aid of oxygen and heterogeneous photocatalysts. In this study, we developed an organic photocatalytic system using covalent triazine/heptazine‐based frameworks (CTF‐TB/CHF‐TB) to enable the B–V oxidation reaction under mild conditions through a cascade reaction pathway. Experimental data and theoretical calculations showed that heptazine/triazine units can “chelate” and decompose the in situ generated H2O2 into hydroxyl radicals (⋅OH). Compared to conventional methods that primarily involve metal‐activated benzaldehyde at elevated temperatures (e.g., 60 °C), the ⋅OH generated in our study can readily cleave the C−H bond of benzaldehyde, forming an active intermediate that drives subsequent sequential processes: O2→H2O2→⋅OH→Ph‐CO⋅→Ph‐COOO⋅. By employing this photocatalytic process, a yield of 91 % and a selectivity of over 99 % were obtained in the oxidation of cyclohexanone to caprolactone at room temperature. This performance is comparable to the state‐of‐the‐art catalysts, and our CHF‐TB catalyst demonstrates impressive reusability, maintaining a high yield after 5 consecutive runs. This work presents a straightforward approach for C−H cleavage by organocatalysts to produce ϵ‐caprolactone in a mild manner by B–V oxidation.

Visible Light-Driven Photocatalysis of Al-Doped SrTiO3: Experimental and DFT Study

Environmental problems associated with water pollution caused by organic dyes have raised serious concerns. In this context, photocatalytic processes have proven to be promising and environmentally friendly methods for water purification utilising abundant solar energy. In this study, a SrTiO3-based photocatalyst was modified by doping with Al ions and the deposition of dual co-catalysts (Rh/Cr2O3 and CoOOH) to enhance the photocatalytic decomposition efficiency of methylene blue (MB). Pure perovskite SrTiO3 was synthesised by chemical precipitation followed by calcination at 1100 °C. Al-doped SrTiO3 with deposited co-catalysts showed 3.2 times higher photocatalytic activity compared to unalloyed SrTiO3 with co-catalysts in MB decomposition under visible radiation. This study highlights the effectiveness of using dual co-catalysts and low-valence metal doping to enhance the efficiency of the photocatalytic decomposition of organic pollutants. The density functional theory analysis results show that the Al doping of SrTiO3 improves charge separation and increases the lifetime of photogenerated electrons and holes while maintaining the size of the forbidden band, which confirms its effectiveness for enhancing photocatalytic activity.

Distinct Pathways Determined by Photocatalytic C─H or O─H Bond Activation for Hydroxyl Compounds Conversion Paired With Hydrogen Production

AbstractSelective control of C─H or O─H bond activation in photocatalytic conversion coupled with hydrogen production is a promising yet challenging goal. Here, an efficient photocatalytic system is reported that can produce high‐valued tartaric acid or formaldehyde and simultaneous producing hydrogen. At optimized conditions, the directional conversion of glycolic acid into tartaric acid is achieved with a selectivity of 76.24%, and the selectivity of methanol oxidation into formaldehyde reaches 88.21%. A high hydrogen production rate of 21.43 mmol·g−1·h−1 is obtained using glycolic acid as substrate. Mechanism studies reveal that α‐C─H bond is preferentially activated in glycolic acid adsorbed on the photocatalyst, while O─H bond is preferentially activated in methanol, forming carbon‐centered radical (•CH(OH)COOH) or oxygen‐centered radical (CH3O•) for subsequent coupling or oxidation reactions. This work demonstrates the selective control of the photocatalytic conversion process of different hydroxyl compounds, providing a new perspective for achieving organic compounds selective activation coupled with hydrogen production.

Electric-Field-Driven Redistribution of Carriers on Catalyst Particles to Improve Photocatalytic Performance.

The photocatalytic performance is primarily determined by carrier separation efficiency. Applying electric fields to enhance carrier separation efficiency and thereby boost catalytic performance has emerged as a promising approach. However, the carrier behavior on catalyst particles under electric fields was still hardly acknowledged. Herein, using single-molecule fluorescence microscopy with high spatiotemporal resolution, the redistribution behavior of carriers on catalyst particles under an electric field was visualized for the first time, which was closely related to the direction and intensity of the electric field. Single-molecule kinetics of the photocatalytic redox reactions induced by carriers have been further obtained, and the results showed that the external electric field had an obvious regulating role in the conversion process and desorption process in this work, which was attributed to the dynamic redistribution of carriers. The improvement of photocatalytic hydrogen evolution reaction (HER) activity further supports the impact of the external electric field on photocatalysis. This work offers new insight into the microscopic regulation mechanism of photocatalytic activity by electric fields and provides new methods for studying the structure-activity relationship in photocatalytic processes.

Improved photocatalytic decomposition of carbaryl pesticide in wastewater using ZnO nanorods

This study explores the enhanced photocatalytic performance of ZnO nanorods (ZnO-R) for degrading the carbaryl pesticide (CB) in wastewater. For comparison, commercial ZnO (ZnO-C) was used to evaluate the differences in the photocatalytic decomposition of CB between ZnO-R and ZnO-C. The results regarding the material properties demonstrated that ZnO-R enhances CB removal performance due to its unique rod shape, which extends light absorption and improves electron-hole separation. The removal rates of the carbaryl pesticide from the aqueous solution using ZnO-R and ZnO-C were 98.2% and 87.3%, respectively. Besides, the presence of other pesticides had a more negative impact on the performance of CB than inorganic contaminants. The degradation rates of CB using ZnO-R in wastewater were 99.8%, 68.2%, and 21.7% under UV, solar, and visible light, respectively. In addition, the degradation mechanism of CB using ZnO-R under UV light was proposed based on the n-type photocatalysis process. This work provides a method for selecting a suitable type of ZnO photocatalyst to control pesticide residue pollutants that are commonly found in agricultural activities.

Optimization and reusability of photocatalytic g-C3N4/W-TiO2/PVDF membranes for degradation of sulfamethazine.

Pharmaceuticals and personal care products (PPCPs) are prevalent emerging pollutants in the aquatic environment. The photocatalysis process has proven high efficiency in degrading PPCPs; however, the fate and repercussions of photocatalyst residuals are a major concern. To avoid that, we developed a composite from graphitic carbon nitride/tungsten doped with titanium dioxide (g-C3N4/W-TiO2) and loaded it on polyvinylidene fluoride (PVDF) membranes by the phase-inversion method. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and other different analyses implied the successful synthesis of g-C3N4/W-TiO2 composite and coating on PVDF membranes. A Box-Behnken design (BBD) was used to optimize the operational parameters, including pH, g-C3N4 ratio in the composite, and initial SMZ concentration by the response surface methodology (RSM). The highest SMZ degradation percentage was 98.60% after 240min of irradiation. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) along with suspect screening was used to identify the intermediate transformation products and propose the SMZ degradation pathway. The loss in membrane activity after five cycles of photocatalytic degradation was about 18%. According to the current study, the photocatalytic membrane g-C3N4/W-TiO2/PVDF is promising for removing sulfonamide antibiotics from wastewater.

Anchoring Perovskite-Like Bi4Ti3O12 and Plasmonic Bi on Defect-Rich Yellow TiO2-x for Enhanced Catalytic Activity toward Degradation of Pollutants upon Visible Light.

The efficiency of heterogeneous photocatalytic processes is currently limited due to the fast recombination of photocarriers, poor light absorption, and inefficient surface catalytic characteristics. In this study, defect-rich yellow TiO2-x nanoparticles (abbreviated as D-TiO2) with high surface area and significant absorption in the visible range were integrated with perovskite-like Bi4Ti3O12 to synthesize binary D-TiO2/Bi4Ti3O12 nanocomposites. To overcome the problem of insufficient activity, we integrated the optimized D-TiO2/Bi4Ti3O12 nanocomposite with plasmonic Bi nanoparticles. Significantly, the optimized D-TiO2/Bi4Ti3O12/Bi-2 nanocomposite efficiently removed tetracycline (TC) in 50 min through production of •OH, h+, and •O2- species, whose removal rate promoted 10.6, 3.18, 5.01, and 1.84 compared with the white TiO2 (abbreviated as W-TiO2), D-TiO2, Bi4Ti3O12, and D-TiO2/Bi4Ti3O12 (20%) photocatalysts, respectively. The outstanding performance of the D-TiO2/Bi4Ti3O12/Bi photocatalyst was attributed to its quantum dot size, low resistance for charge migration, increased surface area, oxygen vacancies in D-TiO2, and developed n-n heterojunction among D-TiO2 and Bi4Ti3O12, which accelerated charge transfer and promoted the generation of active species. Furthermore, the stability tests showed that the TC degradation efficiency still reached 96% after four recycles, indicating the remarkable stability of the photocatalyst. Eventually, the biocompatible nature of the treated solution over the optimized photocatalyst was also revealed from an investigation of the growth of lentil seeds.

Controllable Synthesis of BixOyBrz/TiO2 Heterojunctions with Excellent Visible‐Light‐Driven Photocatalytic Activities for Phenol

AbstractBixOyBrz/TiO2 composites have been synthesized by hydrothermal method, with TiO2 nanoparticles being employed as substrate. During the process of hydrothermal reaction, both temperature and pH have been utilized to effectively regulate the Bi/Br atomic ratio of BixOyBrz/TiO2 composites. In essence, the competitive reaction between OH− and Br− in the solution is the key factor to form BixOyBrz with different Bi/Br atomic ratios. Under visible light, the prepared Bi4O5Br2/TiO2 heterojunction demonstrates higher photocatalytic activity than other BixOyBrz/TiO2 composites for phenol and Rh B. The removal rate of phenol with Bi4O5Br2/TiO2 heterojunction is up to 92.1% after irradiation for 75 min. The excellent photocatalytic activities of Bi4O5Br2/TiO2 heterojunction are mainly attributed to its optimized microstructure and the matching band energy structure, whereby TiO2 nanoparticles with ≈10 nm diameter uniformly arranged on ≈10.2 nm thick Bi4O5Br2 nanosheets. Moreover, the heterojunction structure promotes the separation of photo‐generated electrons and holes in Bi4O5Br2/TiO2, while and h+ are the main active species during its photocatalytic processes.

Core–Shell–Satellite Au@CeO2–Pd Plasmonical Photocatalysts for Suzuki–Miyaura Coupling Reaction

ABSTRACTIntegration of localized surface plasmon resonance (LSPR) metallic nanocrystals into photocatalysis is an intriguing approach for light‐driven organic transformations. However, uncertain direction of hot carriers is a grand challenge, which fails to take full advantage of the LSPR excitation. In this work, core–shell gold@ceria nanosphere–supported segregated palladium species (Au@CeO2–Pd) have developed to steer the light absorption capability and charge carrier migration. Under simulated solar light irradiation, the core–shell–satellite Au@CeO2–Pd exhibited efficient light harvesting and colossal activity in the Suzuki coupling reaction. The plasmon‐induced hot electrons overpassed the Schottky barrier at the Au@CeO2 interfaces and migrated from Au core to CeO2 shell accordingly. Subsequently, the photogenerated electrons and hot electrons migrated from Au@CeO2 core–shells to Pd, which acted as an electron acceptor. Detailed photocatalytic mechanism studies revealed that both photoexcited electrons and holes were the main active species involved in the photocatalytic Suzuki coupling reaction process. In particular, the diphenyl yield over Au@CeO2–Pd catalyst was ~1.7 times higher than that of core–shell–satellite Au@SiO2–Pd, where a 19‐nm‐thick SiO2 shell was introduced to prevent the migration of hot electrons. This distinctly certified that the hot electrons transfer in the core–shell–satellite Au@CeO2–Pd under illumination played an important role to drive Suzuki reaction. Overall, this design of core–shell–satellite Au@CeO2–Pd plasmonic photocatalyst has the potential in the field of photo‐driven organic transformations.

Enhancing the Light‐Driven Photocatalytic Degradation Activity of ZnO Nanoparticles With the Synergistic Incorporation of Er and Tb Elements

ABSTRACTThe existence of organic pollutants in aqueous media has become a vital issue and a critical threat to human health, where organic toxic dyes represent the major contaminants in wastewater. Over the past few years, photocatalytic techniques have garnered a lot of interest in dye removal from wastewater. In this study, a series of ErxTbxZn1 − 2xO nanophotocatalysts (where x = 0.00, 0.01, 0.03, and 0.05) were synthesized and coded as ZET0, ZET1, ZET2, and ZET3 NPs (nanoparticles). The chemical and physical characteristics of the NPs were investigated using Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy‐dispersive X‐ray (EDX) spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) techniques. Further examination by performing photocatalytic experiments, ZET1 NPs demonstrated effective Rhodamine B (RhB) dye degradation within 60 min. It was found that the kinetic rate constant values were 0.008, 0.097, 0.050, and 0.040 min−1 for ZET0, ZET1, ZET2, and ZET3 NPs, respectively. Aside from their remarkable photocatalytic degradation efficiency, these ZET1 photocatalysts are highly stable even after five consecutive cycles. In addition, the active species test revealed that the primary oxidation species involved in the photocatalytic process are holes (h+) and hydroxyl radicals (•OH), and a possible photocatalytic mechanism for degrading RhB by ZET1 photocatalysts was tentatively proposed. The enhancement of the photocatalytic degradation efficiency is due to the low recombination rate of photogenerated charge carriers, as well as a strong synergistic impact of Tb, Er, and ZnO components. Thus, the current study could offer a versatile strategy for the design of new and effective nano photocatalysts for wastewater purification in the future.

Optimized Carbon Coupling for Enhanced Ethylene Production via a Unique Single-Atom-Substrate Synergy Mechanism within Photocatalytic Processes.

The utilization of solar-driven technologies for the direct conversion of methanol (CH3OH) into two or multi-carbon compounds through controlled carbon-carbon (C-C) coupling is an appealing yet challenging objective. In this study, we successfully demonstrate the photocatalytic CH3OH coupling to ethylene (C2H4), a valuable chemical raw material, by employing a carbon nitride-based catalyst. Specifically, we modify the layered polymer carbon nitride (PCN) photocatalyst through the incorporation of Au single atoms (Au1/PCN) using a chemical-scissors method. The synergistic effect between the PCN substrate and the Au single atoms reduces the potential barrier associated with C-C coupling, thereby enhancing the efficiency of CH3OH reforming to C2H4. This investigation not only reveals a novel pathway for C2H4 production via CH3OH reforming but also provides fresh insights into the possibilities of C-C coupling.

Construction of Dual Electric Field Synergistic and Magnetic Recyclable SnFe2O4/ZnO Photocatalyst.

The recombination of photoinduced carriers hampers the photocatalysis process. Construction of the heterojunction and built-in piezoelectric field boosts the separation of electrons and holes. Herein, a novel magnetic recyclable SnFe2O4(SFO)/ZnO composite with enhanced photocatalytic performance based on the dual electric field synergism was proposed for the first time. This composite apparently alleviates the carrier recombination in SFO and extends the absorption spectrum of ZnO to the full spectrum. Consequently, 20%SFO/ZnO exhibits an excellent efficiency, which is 2.45 times that of ZnO and 4.61 times that of SFO, respectively. The differences in size and morphology between the SFO nanoparticles and the ZnO nanorods provide more contact areas, thus enlarging the deformation and enhancing the piezoelectric effect. The heterojunction and the piezoelectric field work together to modulate the transferring of carriers and elevate the photocatalytic activity. This design offers a plausible avenue for preparing efficient recyclable photocatalysts for application.

Preparation of vanadium-titanium magnetite tailings/quartz sand monolithic composite and photocatalytic degradation of rhodamine B

This study focused on the preparation, characterization and photocatalytic performance of a monolithic composite made from vanadium-titanium magnetite tailings and quartz sand. Rhodamine B was used as a pollutant model and the photocatalytic degradation of rhodamine B by the prepared composites was investigated. The results indicated that the composite could effectively degraded Rhodamine B, achieving a degradation rate of 98 % within 20 min under optimal conditions. Investigations on the degradation mechanism revealed that dissolved oxygen, superoxide radicals, and the sensitization of Rhodamine B are crucial to the photocatalytic degradation process of Rhodamine B. These results suggest potential benefits for the comprehensive utilization of vanadium titanomagnetite tailings.

Novel carbon nitride for efficient degradation of organic pollutants and value-added recycled plastics: synergistic effects of nitrogen vacancies and Fe

The introduction of nitrogen vacancies (VN) and iron (Fe) single atoms sites significantly enhances the visible light absorption and charge transfer ability of carbon nitride (CN) catalysts. This paper presents the successful synthesis of a VN-rich, Fe single atoms incorporated CN, a catalyst that demonstrates exceptional degradation performance and cycling stability. The 2-mercaptobenzothiazole (MBT) removal rate by 20Fe-CN reached 99.51% within just 11min under visible light, and the catalyst maintained superior photocatalytic performance upon repeated use. Additionally, the 20Fe-CN/Photo/High-temperature system effectively converted polystyrene (PS) to benzoic acid (BA), achieving a BA yield of 19.73% after 48hours. Under visible light irradiation, the VN sites captured electrons and facilitated their rapid transfer to neighboring Fe sites, enhancing the photocatalytic redox processes. This study also identified ·O2- as the primary active species in the photocatalytic process. This research supports the development of diverse single-atom modified carbon nitride photocatalysts, holding significant potential for wastewater treatment and plastic resource recycling, and providing valuable insights for future photocatalysts in environmental remediation.

Novel 3D plate-like g-C3N4/BiOCl heterojunction as a highly efficient photocatalyst for the degradation of carbofuran in wastewater under visible light irradiation

The g-C3N4/BiOCl (gCN-BCl) heterojunction photocatalyst was synthesized using a low-temperature precipitation method for effective photocatalytic degradation of carbofuran (CBF). All gCN-BCl composites demonstrate greater efficacy in removing CBF compared to its individual constituents. The synergistic effect of incorporating the 0D structured BiOCl onto the 2D structured g-C3N4 was comprehensively examined using various microscopic, X-ray, and spectroscopic analytical techniques. Additionally, optical and photoelectrochemical analyses were conducted. The findings validated that the interaction between the two semiconductors at the heterointerfaces enhanced remarkable physical and structural stability, promoted high charge separation and transfer properties, and improved photocatalytic degradation. Under optimal conditions, 5-gCN-BCl (0.25 g/L) achieved a CBF (5 mg/L) removal efficiency of 95.7 % under visible light irradiation of 120 min, achieving 3.1- and 5.9-times higher degradation rate than the pure BiOCl and g-C3N4, respectively. The radical trapping experiments indicated that the h+ and •O2− were the primary reactive species involved in the CBF degradation. Furthermore, the potential toxicity of CBF and its intermediates was assessed, revealing that the photocatalytic degradation process significantly lowered the ecotoxicity of pesticide wastewater. The potency of 5-gCN-BCl was also evaluated in tap water and real wastewater samples, with CBF degradation efficiencies of 85.8 %, 47.6 %, and 38.7 % in tap water, municipal, and pesticide industry wastewater, respectively. Additionally, artificial neural network (ANN) modeling was employed to predict and optimize the photocatalytic degradation process, providing further insights into the system’s performance. The outcomes of this work offer valuable insights into the development of heterojunction photocatalysts with superior stability and efficacy for eliminating pesticides from water bodies.

Biochar coupling induced charge transfer switching of a NiAl2O4/NiCr2O4 photocatalyst to enhance photocatalytic degradation of tetracycline hydrochloride

A series of novel (NiAl2O4 (NAO)/NiCr2O4 (NCO)) (S1)/GL heterojunction photocatalysts, denoting as x%GL/S1 (x = 5, 10, 15 and 20), were prepared by the polyacrylamide gel method combined with low temperature sintering technique. Various characterizations confirm that there is special interfacial contact and charge transfer between NAO, NCO and GL. The 10%GL/S1 heterojunction exhibited the best photocatalytic activity and cyclic stability for the degradation of tetracycline hydrochloride (TC). Compared to NAO, NCO and NAO/NCO, the degradation efficiency of 10%GL/S1 was significantly improved, and the degradation percentage reached 83.2% within 30 min. The activity of 10%GL/S1 was studied in relation to catalyst content, drug concentration, pH value, water quality, and co-existing anion. Trapping experiments and free radical verification experiments confirmed that the holes, hydroxyl radicals and superoxide radicals played crucial roles in the photocatalysis process. Possible pathways for TC degradation were studied by HPLC-MS, and the ecotoxicity of TC and its degradation intermediates was evaluated by T.E.S.T. software. The charge transfer and photocatalytic mechanisms confirm that the introduction of GL enhances the interfacial interaction between the components, promotes the carrier migration efficiency, provides a large number of active sites for 10%GL/S1 heterojunction, and produces active free radicals after redox reaction with photoinduced electrons, effectively improving the degradation efficiency of TC.

An experimental and theoretical validation of dual role of Fe on improving the photocatalytic performance of doped mixed phase titania

The present work proposes a strategic approach of using Fe doping to form a mixed-phase TiO2 direct Z-scheme catalyst at low onset temperature. The doping-induced modifications are explained from the experimental and theoretical viewpoint. Fe-doped Z-scheme-based mixed-phase TiO2 at optimal calcination temperature (TiFe-400) exhibits maximum photon absorption and reduces charge carrier recombination, enhancing photocatalytic and PEC performance. TiFe-400 has the highest rate constant for the degradation of MB (0.084 min−1 under solar irradiation) and showed exceptional photooxidation current (0.8 mA, 1.3 V vs Ag/AgCl). The Z-scheme formation significantly inhibits the recombination of photocarriers, resulting in a directed migration of charge carriers to the high redox potential mixed-phase TiO2. This migration is validated by identifying the primary reactive species participating in the photocatalytic process. This work, demonstrating both experimental and theoretical approaches, may provide valuable insight into designing stable and inexpensive catalysts for dual applications on an industrial scale.