Search Results (1,288)

Photocatalytic composite materials (TiO₂/SiO₂/BFSF) were first fabricated using the sol–gel method of loading SiO₂ and TiO₂ on blast furnace slag fibers (BFSFs) in sequence and using them as a new carrier. Then, TG-DTA, XRD, BET, SEM-EDS, and UV-Vis absorption spectra, as well as spectrophotometric measurements, were employed to analyze the physicochemical properties of TiO₂. The influence of SiO₂ coating, the number of impregnations in TiO₂ sol, the calcination temperature, and the number of repeated usages on the activity of TiO₂/SiO₂/BFSF was researched by analyzing the degradation of methylene blue (MB) aqueous solution. The results show that SiO₂ could increase the load of TiO₂, impede the growth of TiO₂ grains, and inhibit the recombination of electron–hole pairs, ultimately enhancing the photocatalytic activity of samples. The activity of TiO₂/SiO₂/BFSF first quickly increased and then slowly decreased with an increase in the loading times of TiO₂ sol and calcination temperature. After three impregnations in TiO₂ sol and calcining at 450 °C for 2.5 h, a uniform and compact anatase TiO₂ thin film was deposited on the surface of TiO₂/SiO₂/BFSF, showing the strongest activity. When this sample was used to degrade MB aqueous solution for 180 min under ultraviolet light irradiation, the degradation proportion reached a maximum of 96%. After four reuses, the degradation ratio could still reach 67%. In addition, three potential photocatalytic mechanisms were proposed. Finally, the high-value-added application of blast furnace slag for preparing photocatalytic composite materials was achieved, successfully turning solid waste into “treasure”. Full article

Persistent reactive azo dyes released from textile finishing are a serious threat to water systems, but effective methods using sunlight to break them down are still limited. Everzol Yellow 3RS (EY-3RS) is particularly recalcitrant: past studies have relied almost exclusively on physical adsorption onto natural or modified clays and zeolites, and no photocatalytic pathway employing engineered nanomaterials has been documented to date. This study reports the synthesis, characterization, and performance of a visible-active ternary nanocomposite, Cu₄O₃/ZrO₂/TiO₂, prepared hydrothermally alongside its binary (Cu₄O₃/ZrO₂) and rutile TiO₂ counterparts. XRD, FT-IR, SEM-EDX, UV-Vis, and PL analyses confirm a heterostructured architecture with a narrowed optical bandgap of 2.91 eV, efficient charge separation, and a mesoporous nanosphere-in-matrix morphology. Photocatalytic tests conducted under midsummer sunlight reveal that the ternary catalyst removes 91.41% of 40 ppm EY-3RS within 100 min, markedly surpassing the binary catalyst (86.65%) and TiO₂ (81.48%). Activity trends persist across a wide range of operational variables, including dye concentrations (20–100 ppm), catalyst dosages (10–40 mg), pH levels (3–11), and irradiation times (up to 100 min). The material retains ≈ 93% of its initial efficiency after four consecutive cycles, evidencing good reusability. This work introduces the first nanophotocatalytic strategy for EY-3RS degradation and underscores the promise of multi-oxide heterojunctions for solar-driven remediation of colored effluents. Full article

The photocatalytic performance of heterojunctions is often restricted by inferior contact interface and low charge transfer efficiency. In this work, Ti₃C₂O MXene was crafted with AgI/MoS₂ to produce a Z-scheme heterojunction (AgI/MoS₂/Ti₃C₂O). Interfacial electric fields and chemical bonds were proven to exist in the heterojunction. The interfacial electric fields supplied a powerful driving force, and the interfacial Ti-O-Mo bonds served as an atomic-level channel for synergistically expediting the vectorial transfer of photogenerated carriers. As a result, AgI/MoS₂/Ti₃C₂O exhibited significantly improved photocatalytic activity, demonstrating a high H₂O₂ production rate of 700 μmol·g⁻¹·h⁻¹ and a rapid degradation of organic pollutants. Full article

Photocatalytic redox processes significantly contribute to shaping Earth’s surface environment. Semiconductor minerals exhibiting favorable photocatalytic properties are ubiquitous on rock and soil surfaces. However, the sunlight-responsive characteristics and functions of TiO₂, an excellent photocatalytic material, within natural systems remain incompletely understood, largely due to its wide bandgap limiting solar radiation absorption. This study analyzed surface coating samples, determining their elemental composition, distribution, and mineralogy. The analysis revealed enrichment of anatase TiO₂ and β-carotene. Informed by these observations, laboratory simulations were designed to investigate the synergistic effect of β-carotene on the sunlight-responsive behavior of anatase. Results demonstrate that β-carotene-sensitized anatase exhibited a 64.4% to 66.1% increase in photocurrent compared to pure anatase. β-carotene sensitization significantly enhanced anatase’s electrochemical activity, promoting rapid electron transfer. Furthermore, it improved interfacial properties and acted as a photosensitizer, boosting photo-response characteristics. The sensitized anatase displayed a distinct absorption peak within the 425–550 nm range, with visible light absorption increasing by approximately 17.75%. This study elucidates the synergistic mechanism enhancing the sunlight response between anatase and β-carotene in natural systems and its broader environmental implications, providing new insights for research on photocatalytic redox processes within Earth’s critical zone. Full article

The contamination of water bodies by industrial dyes poses a significant environmental challenge on a global scale. Conventional wastewater treatment methods often suffer from limitations related to high cost, limited efficiency, and potential secondary environmental impacts. Recent advances in photocatalytic technologies have highlighted the potential of metal sulfide-based photocatalysts, particularly those synthesized through environmentally friendly, plant-mediated approaches, as promising alternatives for efficient and sustainable dye degradation. However, despite their promising potential, metal sulfide photocatalysts often suffer from limitations such as photocorrosion, low stability under irradiation, and rapid recombination of charge carriers, which restrict their long-term applicability. In light of these challenges, this review provides a comprehensive examination of the physicochemical characteristics, synthetic strategies, and photocatalytic applications of metal sulfides. Particular emphasis is placed on green synthesis routes employing plant-derived extracts, which offer environmentally benign and sustainable alternatives to conventional methods. Moreover, the review elucidates various modification approaches, most notably, the formation of heterostructures, as viable strategies to enhance photocatalytic efficiency and mitigate the aforementioned drawbacks. The green synthesis of metal sulfides, aligned with the principles of green chemistry, offers a promising route toward the development of sustainable and environmentally friendly water treatment technologies. Full article

The oxygen evolution reaction (OER) plays a central role as an anode in electrocatalytic processes such as energy conversion and storage and the generation of molecular oxygen from the electrolysis of water. Currently, precious metal oxides such as IrO₂ and RuO₂ are recognized as reference OER electrocatalysts with reasonably high activity; however, their widespread use in practical devices has been severely hindered by their high cost and scarcity. It is essential to design alternative OER electrocatalysts made of low-cost and abundant earth elements with significant activity and robustness. We report four new nanocellulose-derived Fe–zeolite nanocomposites, namely Fe/Zeolite@CCNC (1), Fe/Zeolite@CCNF (2), Fe/Zeolite/CNT@CCNC (3), and Fe/Zeolite/CNT@CCNF (4). Two different types of nanocellulose were investigated: nanocellulose nanofibrils and nanocellulose nanocrystals. Characterization with TEM, SEM-EDS, PXRD, and XPS is reported. The nanocomposites exhibited electrocatalytic activity for OER that varies based on the origin of biocarbon and the composition content. The effect of adding carbon nanotubes to the nanocomposites was studied, and an improvement in OER catalysis was observed. The electrochemical double-layer capacitance and electrochemical impedance spectroscopy of the nanocomposites are reported. The nanocomposite 3 exhibited the highest performance, with an onset potential value of 1.654 V and an overpotential of 551 mV, which exceeds the activity of RuO₂ for OER catalysis at 10 mA/cm² in the glassy carbon electrode. A 24 h chronoamperometry study revealed that the catalyst is active for ~2 h under continuous operating conditions. BET surface analysis showed that the crystalline nanocellulose-derived composite exhibited 301.47 m²/g, and the fibril nanocellulose-derived composite exhibited 120.39 m²/g, indicating that the increased nanoporosity of the former contributes to the increase in OER catalysis. Full article

Over efficient photocatalysts, CO₂ photoreduction typically converts CO₂ into low-carbon chemicals, which serve as raw materials for downstream synthesis processes. Here, an efficient composite photocatalyst heterojunction (Cu₂O-u/g-C₃N₄) has been fabricated to reduce CO₂. Graphitic carbon nitride (g-C₃N₄) was synthesized via thermal polymerization of urea at 550 °C, while pre-dispersed Cu₂O derived from urea pyrolysis (Cu₂O-u) was prepared by thermal reduction of urea and CuCl₂·2H₂O at 180 °C. The heterojunction Cu₂O-u/g-C₃N₄ was subsequently constructed through hydrothermal treatment at 180 °C. This heterojunction exhibited a bandgap of 2.10 eV, with dual optical absorption edges at 485 nm and above 800 nm, enabling efficient harvesting of solar light. Under 175 W mercury lamp irradiation, the heterojunction catalyzed liquid-phase CO₂ photoreduction to formic acid, acetic acid, and methanol. Its formic acid production activity surpassed that of pristine g-C₃N₄ by 3.14-fold and TiO₂ by 8.72-fold. Reaction media, hole scavengers, and reaction duration modulated product selectivity. In acetonitrile/isopropanol systems, formic acid and acetic acid production reached 579.4 and 582.8 μmol·h⁻¹·g_cat⁻¹. Conversely, in water/triethanolamine systems, methanol production reached 3061.6 μmol·h⁻¹·g_cat⁻¹, with 94.79% of the initial conversion retained after three cycles. Finally, this work ends with the conclusions of the CO₂ photocatalytic reduction to formic acid, acetic acid, and methanol, and recommends prospects for future research. Full article

The controllable loading of a cocatalyst on a semiconductor is the key to further improving the efficiency and stability of visible-light photocatalytic hydrogen production. It is of great practical significance to load a cocatalyst onto a semiconductor spatially separated to realize space charge separation for efficient photocatalytic hydrogen evolution. The inherent anisotropic morphology of one-dimensional nanorods can provide two spatially separated locations at the tip and side surfaces of the nanorods. In this review, we systematically summarize non-centrosymmetric and centrosymmetric cocatalyst-tipped one-dimensional (1D) photocatalysts, including their preparation method, catalytic hydrogen production performance, and catalytic mechanism. This review will bring new vitality to the design, preparation, and application of cocatalyst-tipped one-dimensional nanorods. Full article

Au-Ag alloy nanoshells (ANSs) were synthesized via chemical reduction, exhibiting superior plasmonic photocatalytic performance. TEM revealed uniform hollow structures (~80 nm), while EDS mapping confirmed homogeneous Au-Ag distribution throughout the shell. According to EDX analysis, the alloy contained 71.40% Ag by weight. XRD verified the formation of a substitutional solid solution without phase separation. The photocatalytic activity was evaluated using p-nitrothiophenol (PNTP) to 4,4′-dimercapto-azobenzene (DMAB) conversion monitored by SERS. UV-Vis spectroscopy showed LSPR peaks of ANSs between Au and Ag NPs, confirming effective alloying. Kinetic studies revealed that ANSs exhibited reaction rates 250–351 times higher than those of Au NPs and 5–10 times higher than those of Ag NPs. This resulted from the synergistic catalysis of Au-Ag and enhanced electromagnetic fields. ANSs demonstrated dual functionality as SERS substrates and photocatalysts, providing a foundation for developing multifunctional nanocatalytic materials. Full article

100 nm thick TiO₂/TiN bilayers with varying thickness ratios were deposited via reactive sputtering of a Ti target in controlled oxygen and nitrogen atmospheres. Post-deposition annealing in air at 600 °C was performed to induce nitrogen diffusion through the oxygen-deficient TiO₂ layer. The resulting changes in morphology and chemical environment were investigated in detail using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. Detailed TEM and XPS analyses have confirmed nitrogen diffusion across the TiO₂ layer, with surface nitrogen concentration and the ratio of interstitial to substitutional nitrogen dependent on the TiO₂/TiN mass ratio. Optical studies demonstrated modifications in optical constants and a reduction of the effective bandgap from 3.2 eV to 2.6 eV due to new energy states introduced by nitrogen doping. Changes in surface free energy induced by nitrogen incorporation showed a correlation to nitrogen doping sites on the surface, which had positive effects on overall photocatalytic activity. Photocatalytic activity, assessed through methylene blue degradation, showed enhancement attributed to nitrogen doping. Additionally, deposition of a 5 nm gold layer on the annealed sample enabled investigation of synergistic effects between nitrogen doping and gold incorporation, resulting in further improved photocatalytic performance. These findings establish the TiO₂/TiN bilayer as a versatile platform for supporting thin gold films with enhanced photocatalytic properties. Full article

TiO₂ was synthesized via the sol–gel method and employed as a support material for the deposition of CdS nanofibers using two novel techniques: impregnation and photodeposition. XRD characterization shows that crystallite size decreases when CdS is incorporated into TiO₂. UV-Vis spectroscopy showed that the bandgap of the CdS/TiO₂ heterostructured nanocomposites decreases compared to the raw TiO₂ support, making them very appropriate for photocatalytic applications in the visible region. The photocatalysts were tested for hydrogen production in methanol–water solutions under visible light conditions. It was observed that the TiC20 photocatalyst prepared by the impregnation method improved the photocatalytic activity compared with photodeposition technique (TiC20FD), achieving a maximum hydrogen production of 570.5 µmol H₂ ${\mathrm{g}}_{\mathrm{c}\mathrm{a}\mathrm{t}}^{-1}$ h⁻¹, while the latter attained 383.4 µmol H₂ ${\mathrm{g}}_{\mathrm{c}\mathrm{a}\mathrm{t}}^{-1}$ h⁻¹. Full article

Reverse osmosis (RO) concentrated water can be effectively treated with catalytic ozone oxidation technology, an effective advanced oxidation process. In order to provide a thorough reference for the safe treatment and reuse of RO concentrated water, this paper examines the properties of RO concentrated water, such as its high salt content, high levels of organic pollutants, and low biochemistry. It also examines the mechanism of its role in treating RO concentrated water and combs through its applications in municipal, petrochemical, coal chemical, industrial parks, and other industries. The study demonstrates that ozone oxidation technology can efficiently eliminate the organic matter that is difficult to break down in RO concentrated water and lower treatment energy consumption; however, issues with free radical inhibitor interference, catalyst recovery, and stability still affect its use. Future research into multi-technology synergistic processes, the development of stable and effective non-homogeneous catalysts, and the promotion of their use at the “zero discharge” scale for industrial wastewater are all imperative. Full article

The conversion of CO₂ into CH₄ through the Sabatier reaction is one of the key processes that can reduce CO₂ emissions into the atmosphere. This work aims to develop Ni-Al aerogel-based thermo-photocatalysts with large specific surface areas prepared using a sol–gel method and subsequent supercritical drying in CO₂. Different Al/Ni molar ratios were selected for the development of the catalysts, characterized using ICP-OES, N₂ adsorption–desorption isotherms, XRD, H₂-TPR, TEM, UV-Vis DRS, and XPS techniques. Thermo-photocatalytic activity tests were performed in a photoreactor with two different light sources (λ = 365 nm, λ = 470 nm) at a temperature range from 300 °C to 450 °C and a pressure of 10 bar. The catalyst with the highest Ni loading (AG 1/3) produced the best catalytic results, reaching CO₂ conversion and CH₄ selectivity levels of 82% and 100%, respectively, under visible light at 450 °C. In contrast, the catalysts with the lowest nickel loading produced the lowest results, most likely due to their low amounts of active Ni. These results suggest that supercritical drying is an efficient method for developing active thermo-photocatalysts with high Ni dispersion, suitable for Sabatier reactions under mild reaction conditions. Full article

The development of cost-effective and scalable air/oxygen electrode materials is crucial for the advancement of Zn–air batteries (ZABs). Porous carbon materials doped with heteroatoms have attracted considerable attention in energy and environmental fields because of their tunable nanoporosity and high electrical conductivity. In this work, we report the synthesis of a three-dimensional (3D) N and P co-doped porous carbon (PA@pDC-1000), derived from a conjugated polyaniline–phytic acid polymer. The cross-linked, rigid conjugated polymeric framework plays a crucial role in maintaining the integrity of micro- and mesoporous structures and promoting graphitization during carbonization. As a result, the material exhibits a hierarchical pore structure, a high specific surface area (1045 m² g⁻¹), and a large pore volume (1.02 cm³ g⁻¹). The 3D N, P co-doped PA@pDC-1000 catalyst delivers a half-wave potential of 0.80 V (vs. RHE) and demonstrates a higher current density compared to commercial Pt/C. A primary ZAB utilizing this material achieves an open-circuit voltage of 1.51 V and a peak power density of 217 mW cm⁻². This metal-free, self-templating presents a scalable route for the generating and producing of high-performance oxygen reduction reaction catalysts for ZABs. Full article

As renewable energy technologies advance, identifying efficient photocatalytic materials for water splitting to produce hydrogen has become an important research focus in materials science. This study presents a multi-task regression model (MTRM) designed to predict the conduction band minimum (CBM), valence band maximum (VBM), and solar-to-hydrogen efficiency (STH) of inorganic materials. Utilizing crystallographic and band gap data from over 15,000 materials in the SNUMAT database, machine-learning methods are applied to predict CBM and VBM, which are subsequently used as additional features to estimate STH. A deep neural network framework with a multi-branch, multi-task regression structure is employed to address the issue of error propagation in traditional cascading models by enabling feature sharing and joint optimization of the tasks. The calculated results show that, while traditional tree-based models perform well in single-task predictions, MTRM achieves superior performance in the multi-task setting, particularly for STH prediction, with an MSE of 0.0001 and an R² of 0.8265, significantly outperforming cascading approaches. This research provides a new approach to predicting photocatalytic material performance and demonstrates the potential of multi-task learning in materials science. Full article