Search Results (93)

This study presents the development of Cu-doped NiMo/TiO₂ photoelectrocatalysts for simultaneous green hydrogen production and pharmaceutical pollutant removal under simulated solar irradiation. The catalysts were synthesized via wet impregnation (15 wt.% total metal loading with 0.6 wt.% Cu) and thermally treated at 400 °C and 900 °C to investigate structural transformations and catalytic performance. Comprehensive characterization (XRD, BET, SEM, XPS) revealed phase transitions, enhanced crystallinity, and redistribution of redox states upon Cu incorporation, particularly the formation of NiTiO₃ and an increase in oxygen vacancies. Crystallite sizes for anatase, rutile, and brookite ranged from 21 to 47 nm at NiMoCu400, while NiMoCu900 exhibited only the rutile phase with 55 nm crystallites. BET analysis showed a surface area of 44.4 m²·g⁻¹ for NiMoCu400, and electrochemical measurements confirmed its higher electrochemically active surface area (ECSA, 2.4 cm²), indicating enhanced surface accessibility. In contrast, NiMoCu900 exhibited a much lower BET surface area (1.4 m²·g⁻¹) and ECSA (1.4 cm²), consistent with its inferior photoelectrocatalytic performance. Compared to previously reported binary NiMo/TiO₂ systems, the ternary NiMoCu/TiO₂ catalysts demonstrated significantly improved hydrogen production activity and more efficient photoelectrochemical degradation of paracetamol. Specifically, NiMoCu400 showed an anodic peak current of 0.24 mA·cm⁻² for paracetamol oxidation, representing a 60% increase over NiMo400 and a cathodic current of −0.46 mA·cm⁻² at −0.1 V vs. RHE under illumination, nearly six times higher than the undoped counterpart (–0.08 mA·cm⁻²). Mott–Schottky analysis further revealed that NiMoCu400 retained n-type behavior, while NiMoCu900 exhibited an unusual inversion to p-type, likely due to Cu migration and rutile-phase-induced realignment of donor states. Despite its higher photosensitivity, NiMoCu900 showed negligible photocurrent, confirming that structural preservation and surface redox activity are critical for photoelectrochemical performance. This work provides mechanistic insight into Cu-mediated photoelectrocatalysis and identifies NiMoCu/TiO₂ as a promising bifunctional platform for integrated solar-driven water treatment and sustainable hydrogen production. Full article

Despite significant progress in photoelectrochemical (PEC) water splitting, high fabrication costs and limited efficiency of photoanodes hinder practical applications. Bismuth vanadate (BiVO₄), with its low cost, non-toxicity, and suitable band structure, is a promising photoanode material but suffers from poor charge transport, sluggish surface kinetics, and photocorrosion. In this study, porous monoclinic BiVO₄ films are fabricated via a simplified successive ionic layer adsorption and reaction (SILAR) method, followed by borate treatment and PEC deposition of NiFeO_x. The resulting B/BiVO₄/NiFeO_x photoanode exhibits a significantly enhanced photocurrent density of 2.45 mA cm⁻² at 1.23 V vs. RHE—5.3 times higher than pristine BiVO₄. It also achieves an ABPE of 0.77% and a charge transfer efficiency of 79.5%. These results demonstrate that dual surface modification via borate and NiFeO_x is a cost-effective strategy to improve BiVO₄-based PEC water splitting performance. This work provides a promising pathway for the scalable development of efficient and economically viable photoanodes for solar hydrogen production. Full article

Titanium dioxide (TiO₂) is a wide-bandgap semiconductor material with broad application potential, known for its excellent photocatalytic performance, high chemical stability, low cost, and non-toxicity. These properties make it highly attractive for applications in photovoltaic energy, environmental remediation, and optoelectronic devices. For instance, TiO₂ is widely used as a photocatalyst for hydrogen production via water splitting and for degrading organic pollutants, thanks to its efficient photo-generated electron–hole separation. Additionally, TiO₂ exhibits remarkable performance in dye-sensitized solar cells and photodetectors, providing critical support for advancements in green energy and photoelectric conversion technologies. Boron-doped diamond (BDD) is renowned for its exceptional electrical conductivity, high hardness, wide electrochemical window, and outstanding chemical inertness. These unique characteristics enable its extensive use in fields such as electrochemical analysis, electrocatalysis, sensors, and biomedicine. For example, BDD electrodes exhibit high sensitivity and stability in detecting trace chemicals and pollutants, while also demonstrating excellent performance in electrocatalytic water splitting and industrial wastewater treatment. Its chemical stability and biocompatibility make it an ideal material for biosensors and implantable devices. Research indicates that the combination of TiO₂ nanostructures and BDD into heterostructures can exhibit unexpected optical and electrical performance and transport behavior, opening up new possibilities for photoluminescence and rectifier diode devices. However, applications based on this heterostructure still face challenges, particularly in terms of photodetector, photoelectric emitter, optical modulator, and optical fiber devices under high-temperature conditions. This article explores the potential and prospects of their combined heterostructures in the field of optoelectronic devices such as photodetector, light emitting diode (LED), memory, field effect transistor (FET) and sensing. TiO₂/BDD heterojunction can enhance photoresponsivity and extend the spectral detection range which enables stability in high-temperature and harsh environments due to BDD’s thermal conductivity. This article proposes future research directions and prospects to facilitate the development of TiO₂ nanostructured materials and BDD-based heterostructures, providing a foundation for enhancing photoresponsivity and extending the spectral detection range enables stability in high-temperature and high-frequency optoelectronic devices field. Further research and exploration of optoelectronic devices based on TiO₂-BDD heterostructures hold significant importance, offering new breakthroughs and innovations for the future development of optoelectronic technology. Full article

Contaminants of emerging concern (CECs), including pharmaceuticals and perfluorinated compounds, pose a growing threat to water quality due to their persistence and resistance to conventional treatment methods. In this context, photocatalytic processes capable of promoting both oxidative and reductive transformations have attracted increasing attention. This study explores the synthesis and performance of a SnS₂-TiO₂ heterojunction photocatalyst, designed to facilitate such reactions under solar and UV-A light. The composite was synthesized via the hydrothermal method and thoroughly characterized for its morphological, structural, surface, and semiconducting properties. The results confirmed the formation of a type-II heterojunction with improved visible-light absorption and suppressed charge recombination. Photoelectrochemical measurements indicated enhanced charge separation and favorable band-edge alignment for reductive processes. Photocatalytic experiments with amoxicillin (AMX) and perfluorooctanoic acid (PFOA) revealed distinct degradation behaviors: AMX was predominantly degraded via superoxide-mediated reductive pathways, whereas PFOA exhibited limited transformation, likely proceeding via a combination of oxidative and reductive mechanisms. While overall removal efficiencies were moderate, this study highlights the role of band structure engineering and heterojunction design in tailoring photocatalytic behavior. The SnS₂-TiO₂ system serves as a promising platform for further development of composite materials to address the challenge of CECs in water treatment. Full article

Photodegradation is a sustainable green technology that has been studied worldwide, especially for wastewater treatment. The calcination temperature has an important impact on the physicochemical properties of the prepared photocatalysts. In this study, a ternary photocatalyst of Cu₂O/WO₃/TiO₂ (CWT) was successfully synthesized using an ultrasonic-assisted hydrothermal technique, and the calcination temperature was varied from 500 to 800 °C. The characterization outcomes proved that the anatase phase titanium dioxide (TiO₂) in the CWT composite transformed to rutile phase TiO₂ when the calcination temperature reached 700 °C and 800 °C. The surface area of the CWT composite decreased from 35.77 to 8.09 m².g⁻¹ and the particle size of the CWT composite increased from 39.11 to 180.25 nm with an increasing calcination temperature from 500 to 800 °C. Photoelectrochemical (PEC) studies showed the charge-transfer resistance of 208.10 Ω, electron lifetime of 32.48 ms, current density of 1.40 mA.cm⁻², transient photovoltage of 0.53 V, and p-n heterojunction properties for CWT-500. Reactive Black 5 (RB5) was used as the model pollutant to examine the photodegradation performance. The photodegradation rate of CWT-500 was the highest (0.70 × 10⁻² min⁻¹) due to its large surface area, effective separation of photoexcited electron-hole pairs, and low photoexcited charge carrier recombination rate. Full article

This study presents the development and application of a batch-type photoelectrochemical reactor employing advanced oxidation processes (AOPs) with in situ generated TiO₂ particles for the efficient degradation of azo dyes. The reactor uses titanium sheets as electrodes, facilitating the electrochemical generation of TiO₂, which acts as a photocatalyst under UV light. This study specifically targets azo dyes frequently encountered in industrial wastewater, focusing on Brilliant Blue, Erythrosine, and Tartrazine, which together form the Navy Blue dye composition. The experimental methodology replicates real-world conditions, ensuring the results are representative of practical scenarios. Key findings demonstrate that the in situ production of TiO₂ enables effective heterogeneous photocatalysis, achieving significant dye degradation rates. This research highlights the novelty of combining in situ TiO₂ generation with a batch-type reactor, offering advantages in cost-effectiveness, scalability, and environmental impact. Comparative analysis with existing methods underscores the reactor’s potential for industrial applications, particularly in wastewater treatment. Furthermore, this study outlines the mechanistic insights into dye degradation and provides a foundation for optimizing photocatalytic processes to address environmental challenges. Full article

The application of membrane sensors for the detection and quantification of pharmaceutical environmental contaminants has become a significant goal in recent years. Due to the widespread application of levofloxacin hemihydrate (LEVO) in medicine, its occurrence in the environment, especially in surface water bodies like rivers, is quite likely. Extended exposure of river water to sunlight and the photo-degradability of LEVO may facilitate its photo-degradation. To measure LEVO in the presence of its principal photo-degradants, two sensitive and selective membrane electrodes were designed. A polyvinyl chloride electrode (PVCE) and a screen-printed electrode (SPE) were constructed for the selective analysis of the investigated drug. Phosphomolybdic acid was used to prepare a lipophilic ion pair with the studied drug. All test parameters were optimized to achieve the best electrochemical performance. The electrodes demonstrated a linear range from 1 × 10⁻⁶ M to 1 × 10⁻² M. The PVCE and SPE demonstrated slopes of 55.80 ± 0.70 mV/decade and 56.90 ± 0.50 mV/decade, respectively. The aforementioned sensors demonstrated satisfactory performance within a pH range of 3.0 to 5.0. The fabricated sensors were successfully utilized to accurately quantify LEVO in the presence of its primary photo-degradants. The membranes were effectively utilized to measure LEVO in river water samples without requiring pre-treatment processes. Full article

This study investigated a hybrid electrode based on titanium/titanium dioxide nanowires/reduced graphene oxide (Ti-TiO₂(NW)/rGO) that was developed in two stages. The Ti-TiO₂(NW)/rGO was obtained by hydrothermal treatment in a mixed solution of H₂O₂ and melamine for Ti-TiO₂ support, followed by a simple spin-coating deposition method and thermal oxidation in a controlled atmosphere of nitrogen gas (99%). The as-prepared structures of electrodes were characterized using ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). In addition, the electrochemical behavior was assessed by cyclic voltammetry (CV) in a 1M HNO₃-supporting electrolyte and in the presence of 4 mM K₄Fe(CN)₆ 3H₂O to determine the electroactive surface area and apparent diffusion coefficient of the hybrid electrode. The development of the Ti-TiO₂(NW)/rGO hybrid electrode provides a sensitive method for photo-electrooxidation of doxorubicin due to exploiting the synergistic and remarkable properties of the nanowires of TiO₂ and of reduced graphene oxide (rGO) layer on the electrode surface. Full article

Zinc oxide (ZnO) photocatalysts have emerged as a promising material for environmental and energy applications due to their exceptional photocatalytic properties. Initially recognized for their efficiency under ultraviolet (UV) light, recent advancements have focused on enhancing ZnO’s visible light activity (VLA) to address its inherent limitations. This review provides an overview of ZnO’s structure, electronic properties, and photocatalytic mechanisms. Various strategies for modifying ZnO to harness visible light, including metal and non-metal doping, dye sensitization, and semiconductor coupling, are discussed. Special emphasis is placed on the mechanisms behind visible light absorption and reactive oxygen species (ROS) generation, as deduced through physicochemical and photoelectrochemical analyses. The applications of ZnO in environmental remediation are comprehensively explored, particularly for water treatment, disinfection, and air purification. The photocatalytic degradation of pollutants, including persistent organic compounds, pharmaceuticals, dyes, and pesticides, using ZnO is reviewed and compared with conventional UV-activated ZnO materials. This review underscores the potential of ZnO as an efficient and sustainable solution for environmental purification. Full article

Tetracycline (TCs) is widely used in the treatment of human and animal infectious disease. TCs gives rise to a growing threat to the human health and environment protection due to its overuse. Therefore, it is important to remove TCs contaminants from waste effluents. In this work, MoS₂@Fe₃O₄ catalytic material was fabricated by the simple hydrothermal method, which was applied in the photo-Fenton system to degrade TCs. The crystal structure, surface morphology, elemental composition, chemical state, electrochemical properties, and separability of MoS₂@Fe₃O₄ catalytic materials were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and vibrating sample magnetometry (VSM). Furthermore, MoS₂@Fe₃O₄ could degrade 98.6% of TCs within 60 min under the optimum reaction conditions (the catalyst dosage of 3 g/L, H₂O₂ concentration of 5 mmol/L, the initial TCs concentration of 50 mg/L, and the initial pH of 5), which was a significant increase compared with pure Fe₃O₄. MoS₂ can accelerate the Fe³⁺/Fe²⁺ cycle through electron transfer from Mo⁴⁺ to Fe³⁺, resulting in the improvement in the degradation efficiency of TCs. The quenching and electron paramagnetic resonance (EPR) results showed that OH^• and photogenic hole h+ was the main active species in the photo-Fenton system. What is more, MoS₂@Fe₃O₄ catalytic materials had remarkable stability and reusability, and can be handily regained via magnetic separation technology in a real scenario. Full article

Considering the poor conductivity of Fe₂O₃ and the weak oxygen evolution reaction associated with it, surface hole accumulation leads to electron hole pair recombination, which inhibits the photoelectrochemical (PEC) performance of the Fe₂O₃ photoanode. Therefore, the key to improving the PEC water oxidation performance of the Fe₂O₃ photoanode is to take measures to improve the conductivity of Fe₂O₃ and accelerate the reaction kinetics of surface oxidation. In this work, the PEC performances of Fe₂O₃ photoanodes are synergistically improved by combining loaded an FeOOH cocatalyst and oxygen vacancy doping. Firstly, amorphous FeOOH layers are successfully prepared on Fe₂O₃ nanostructures through simple photoassisted electrodepositon. Then oxygen vacancies are introduced into FeOOH-Fe₂O₃ through plasma vacuum treatment, which reduces the content of Fe-O (O_L) and Fe-OH (-OH), jointly promoting the generation of oxygen vacancies. Oxygen vacancy can increase the concentration of most carriers in Fe₂O₃ and form photo-induced charge traps, promoting the separation of electron holes and enhancing the conductivity of Fe₂O₃. The other parts of -OH act as oxygen evolution catalysts to reduce the reaction obstacle of water oxidation and promote the transfer of holes to the electrode/electrolyte interface. The performance of FeOOH-Fe₂O₃ after plasma vacuum treatment has been greatly improved, and the photocurrent density is about 1.9 times higher than that of the Fe₂O₃ photoanode. The improvement in the water oxidation performance of PEC is considered to be the synergistic effect of the cocatalyst and oxygen vacancy. All outstanding PEC response characteristics show that the modification of the cocatalyst and oxygen vacancy doping represent a favorable strategy for synergistically improving Fe₂O₃ photoanode performance. Full article

The elimination of pollutants in real water and wastewater is a challenge for the successful application of electrooxidation processes (EOPs). The presence of inorganic salts in the reaction medium is of great relevance during EOPs, with active participation in the electrochemical reactions. A revision of the reported devices used in the decontamination and disinfection of real wastewater demonstrated the main drawbacks of efficiently removing pollutants. However, the combination of photocatalytic processes with electrochemical technologies has been explored to improve overall efficiency and reduce energy consumption. A wide variety of materials, mainly metals, polymers, carbon and graphite derivatives, oxides, and MOFs, as well as their combinations, have been applied to electrodes and photoactive coatings. The deposition of the active layer has been enriched with novel designs, including porous hierarchical growth and 3D printing. The use of powerful characterization techniques allows for the study of the composition, structure, surface, and photo- and electrochemical performance of the fabricated electrodes. The simultaneous optimization of the operating conditions, parameters, and reactors must be specifically defined according to each water matrix. This approach will increase the efficiency of the whole process and contribute to cost savings. Economic contributions have been revised to calculate the cost of wastewater treatment. Full article

A series of flexible polyacrylonitrile/TiO₂ (PAN/P25) multi-porous nanotubular membranes were successfully constructed by facile electrospinning combined with an ethylene glycol solvothermal induce strategy. The effects of P25 dosage and solvothermal time on the morphology of samples were systematically investigated, which were characterized in terms of surface morphology, microstructure, specific surface area, thermal analysis, wettability, photoelectrochemical and fluorescence spectra. Rhodamine B (RhB) and Escherichia coli (E. coli) were employed as simulated pollutants to evaluate photocatalytic degradation and antibacterial properties of the PAN/P25-3 multi-porous nanotubular membrane. The PAN/P25-3 membrane exhibited the highest photocatalytic degradation efficiency, with 96.1% degradation of RhB within 120 min under a xenon lamp light source and a photocatalytic inactivation rate of 95.8% for E. coli under 365 nm monochromatic light irradiation. The photocatalytic degradation mechanism of the PAN/P25-3 multi-porous nanotubular membrane for RhB was deduced from the results of 3D-EEM fluorescence and scavenger experiments of reactive species. Additionally, the cyclic photodegradation experiments demonstrated that the PAN/P25-3 membrane maintained excellent stability and photocatalytic performance after multiple degradation cycles, confirming its potential for sustainable wastewater treatment applications. Full article

The utilization of membrane sensors for the monitoring and determination of pharmaceutical environmental pollutants has emerged as a crucial objective in recent years. Given the extensive use of chlorpromazine hydrochloride (CPZ) in medicine, its presence in the environment, particularly in surface water such as rivers, is highly probable. Prolonged exposure of river water to sunlight and the photo-degradability of CPZ may enhance its photo-degradation. For the purpose of measuring CPZ in the presence of its primary photo-degradants, two sensitive and selective membrane electrodes were developed. These were synthesized utilizing two ion-pairing agents: sodium tetraphenylborate (TPB) and phosphotungstic acid (PTA). The electrodes exhibited a linear range that extended from 1 × 10⁻⁶ M to 1 × 10⁻² M. The membrane electrodes of CPZ-TPB and CPZ-PTA exhibited slopes of 59.90 ± 0.60 mV/decade and 58.90 ± 0.80 mV/decade, respectively. The sensors mentioned above showed acceptable performance in a pH range of 2.0 to 6.0. All test parameters were optimized to provide superior electrochemical performance. The fabricated membranes were effectively employed to sensitively quantify CPZ in the presence of its principal photodegradants. The developed sensors were successfully employed to quantify CPZ in river water samples without necessitating pre-treatment procedures. Full article

Bismuth-based compounds have been regarded as a kind of promising material due to their narrow bandgap, high carrier mobility, low toxicity, and strong oxidation ability, showing potential applications in the field of photoelectrochemical (PEC) activities. They can be applied in sustainable energy production, seawater desalination and treatment, optical detection and communication, and other fields. As a member of the broader family of bismuth-based materials, β-Bi₂O₃ exhibits significant advantages for applications in engineering, including high photoelectric response, stability in harsh environments, and excellent corrosion resistance. This paper presents the synthesis of β-Bi₂O₃ thin films utilizing the mist chemical vapor deposition (CVD) method at the optimal temperature of 400 °C. Based on the β-Bi₂O₃ thin film synthesized at optimal temperature, a PEC-type photodetector was constructed with the highest responsivity R of 2.84 mA/W and detectivity D of 6.01 × 10¹⁰ Jones, respectively. The photodetection performance was investigated from various points like illumination light wavelength, power density, and long-term stability. This study would broaden the horizontal and practical applications of β-Bi₂O₃. Full article