Effective charge separation in the rutile TiO2 nanorod-coupled α-Fe2O3 with exceptionally high visible activities

Do Fe2O3/TiO2 heterojunctions improve the wastewater disinfection process?

This work examines the photocatalytic capacity of Fe2O3-TiO2 catalysts for inactivating Enterococcus faecalis in water and compares it to a peroxide-assisted process. The influence of H2O2, PMS, pH, and temperature is assessed. Material stability and free radical species involved in disinfection are also evaluated. The main findings indicate that Fe2O3-TiO2 photocatalysts do not improve disinfection results compared to mesoporous TiO2, achieving total disinfection after 90 min. Using PMS and H2O2 as oxidants in Catalytic Wet Peroxide Oxidation, system 0.15 mM PMS/0.5 g/L mTiO2 under solar radiation reduced the required time to 10 min for total bacterial inactivation (extended to 30 min with diclofenac present due to competition for radicals), whereas H2O2 took approximately 70 min. The Fe2O3-TiO2 heterojunction catalysts (Cat2 - Cat5) showed no improvement, likely due to bacteria-photocatalyst interactions preventing oxidants from reacting with Fe on the catalyst surface. EPR analyses revealed hydroxyl radicals as the predominant oxidizing species (over 90% abundance). Additionally, higher pH values (>6) decreased inactivation kinetics, while increasing the temperature to 40 °C improved it by up to 120%. The photocatalyst showed low stability from the fourth use, with a 40% decrease in bacterial inactivation kinetics.

Solvent-Assisted Crystallization of an α-Fe2O3 Electron Transport Layer for Efficient and Stable Perovskite Solar Cells Featuring Negligible Hysteresis

Inorganic-organic metal halide perovskite solar cells (PSCs) show power conversion efficiency values approaching those of state-of-the-art silicon solar cells. In a quest to find suitable charge transport materials in PSCs, hematite (α-Fe₂O₃) has emerged as a potential electron transport layer (ETL) in n-i-p planar PSCs due to its low cost, UV light stability, and nontoxicity. Yet, the performance of α-Fe₂O₃-based PSCs is far lower than that of state-of-the-art PSCs owing to the poor quality of the α-Fe₂O₃ ETL. In this work, solvent-assisted crystallization of α-Fe₂O₃ ETLs was carried out to examine the impact of solvents on the optoelectronic properties of α-Fe₂O₃ thin films. Among the various solvents used in this study (deionized water, ethanol, iso-propanol, and iso-butanol), optimized ethanol-based α-Fe₂O₃ ETLs lead to champion device performance with a power conversion efficiency of 13% with a reduced hysteresis index of 0.04 in an n-i-p-configured PSC. The PSC also exhibited superior long-term inert and ambient stabilities compared to a reference device made using a SnO₂ ETL. Through a series of experiments spanning structural, morphological, and optoelectronic properties of the various α-Fe₂O₃ thin films and their devices, we provide insights into the reasons for the improved photovoltaic performance. It is noted that the formation of a pinhole-free compact morphology of ETLs facilitates crack-free surface coverage of the perovskite film atop an α-Fe₂O₃ ETL, reduces interfacial recombination, and enhances charge transfer efficiency. This work opens up the route toward novel ETLs for the development of efficient and photo-stable PSCs.

Fe-Ce/Layered Double Hydroxide Heterostructures and Their Derived Oxides: Electrochemical Characterization and Light-Driven Catalysis for the Degradation of Phenol from Water

Fe-Ce/layered double hydroxides (LDHs) were synthesized via a facile route by exploiting the "structural memory" of the LDH when the calcined MgAlLDH and ZnAlLDH were reconstructed in the aqueous solutions of FeSO₄/Ce(SO₄)₂. XRD analysis shows the formation of heterostructured catalysts that entangle the structural characteristics of the LDHs with those of Fe₂O₃ and CeO₂. Furthermore, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, TG/DTG, SEM/EDX and TEM results reveal a complex morphology defined by the large nano/microplates of the reconstructed LDHs that are tightly covered with nanoparticles of Fe₂O₃ and CeO₂. Calcination at 850 °C promoted the formation of highly crystallized mixed oxides of Fe₂O₃/CeO₂/ZnO and spinels. The photo-electrochemical behavior of Fe-Ce/LDHs and their derived oxides was studied in a three-electrode photo-electrochemical cell, using linear sweep voltammetry (LSV), Mott-Schottky (M-S) analysis and photo-electrochemical impedance spectroscopy (PEIS) measurements, in dark or under illumination. When tested as novel catalysts for the degradation of phenol from aqueous solutions, the light-driven catalytic heterojunctions of Fe-Ce/LDH and their derived oxides reveal their capabilities to efficiently remove phenol from water, under both UV and solar irradiation.

Synthesis of Fe2O3/Mn2O3 Nanocomposites and Impregnated Porous Silicates for Dye Removal: Insights into Treatment Mechanisms

Fe2O3/Mn2O3 nanocomposites and impregnated porous silicates (Fe2O3/Mn2O3@SiO2 [FMS]) were prepared and investigated as catalytic adsorbents. The catalysts were applied for cationic and anionic dye pollutants in the adsorption, Fenton reaction, and photocatalysis processes at a pH of 7. Fe2O3/Mn2O3 nanoparticles (FM-NPs) were prepared using the co-precipitation method and were impregnated in SiO2 by the sol–gel process. The synthesized materials were characterized using various sophisticated techniques. Results indicated that the impregnation of bi-metallic NPs in SiO2 increased the surface area, and the function of the adsorbent also improved. FMS showed a significant adsorption effect, with 79.2% rhodamine B removal within 15 min. Fenton and photocatalyst reaction showed removal rates of 85.3% and 97.9%, respectively, indicating that negatively charged porous silicate attracts cationic pollutants. In the case of the anionic pollutant, Congo red, the adsorption reaction of FMS did not occur, and the removal rate of the photocatalyst reaction was 79%, indicating the repulsive force between the negatively charged silica and the anionic dye. Simultaneously, bi-metal-bonded FM-NPs facilitated the photocatalytic reaction, reducing the recombination of electron-hole pairs. This study provides new insights into the synthesis of FM-NPs and FMS as photocatalytic adsorbents and their photocatalytic mechanisms based on reaction conditions and contaminant characteristics. The developed materials have potential applications for environmental mitigation.

Systematic Investigation of Structural, Morphological, Thermal, Optoelectronic, and Magnetic Properties of High-Purity Hematite/Magnetite Nanoparticles for Optoelectronics

Iron oxide nanoparticles, especially hematite (α-Fe2O3) and magnetite (Fe3O4) have attained substantial research interest in various applications of green and sustainable energy harnessing owing to their exceptional opto-magneto-electrical characteristics and non-toxicity. In this study, we synthesized high-purity hematite and magnetite nanoparticles from a facile top-down approach by employing a high-energy ball mill followed by ultrasonication. A systematic investigation was then carried out to explore the structural, morphological, thermal, optoelectrical, and magnetic properties of the synthesized samples. The experimental results from scanning electron microscopy and X-ray diffraction corroborated the formation of highly crystalline hematite and magnetite nanoparticles with average sizes of ~80 nm and ~50 nm, respectively. Thermogravimetric analysis revealed remarkable results on the thermal stability of the newly synthesized samples. The optical studies confirmed the formation of a single-phase compound with the bandgaps dependent on the size of the nanoparticles. The electrochemical studies that utilized cyclic voltammetry and electrochemical impedance spectroscopy techniques verified these iron oxide nanoparticles as electroactive species which can enhance the charge transfer process with high mobility. The hysteresis curves of the samples revealed the paramagnetic behavior of the samples with high values of coercivity. Thus, these optimized materials can be recommended for use in future optoelectronic devices and can prove to be potential candidates in the advanced research of new optoelectronic materials for improved energy devices.

Solvent Etching Process for Graphitic Carbon Nitride Photocatalysts Containing Platinum Cocatalyst: Effects of Water Hydrolysis on Photocatalytic Properties and Hydrogen Evolution Behaviors

In this study, we synthesized Pt/g-C₃N₄ photocatalysts modified by a solvent etching process where ethanol (Pt/CN0), water (Pt/CN100), and a 50:50 mixture (Pt/CN50) were used as a solvent, and investigated the optimal properties of g-C₃N₄ to prepare the best Pt/g-C₃N₄ for photocatalytic hydrogen evolution. From diverse characterizations, water was proven to be a stronger solvent agent, resulting in not only the introduction of more O-functional groups onto the g-C₃N₄ surface, but also the degradation of a regular array of tri-s-triazine units in the g-C₃N₄ structure. While the addition of O-functional groups positively influenced the oxidation state of the Pt cocatalyst and the hydrogen production rate, the changes to g-C₃N₄ structure retarded charge transfer on its surface, inducing negative effects such as fast recombination and less oxidized Pt species. Pt/CN50 that was synthesized with the 50:50 solvent mixture exhibited the highest hydrogen production rate of 590.9 µmol g⁻¹h⁻¹, while the hydrogen production rates of Pt/CN0 (with pure ethanol solvent) and Pt/CN100 (with pure water solvent) were 462.7, and 367.3 µmol g⁻¹h⁻¹, respectively.

Heterojunction Nanomedicine

Exogenous stimulation catalytic therapy has received enormous attention as it holds great promise to address global medical issues. However, the therapeutic effect of catalytic therapy is seriously restricted by the fast charge recombination and the limited utilization of exogenous stimulation by catalysts. In the past few decades, many strategies have been developed to overcome the above serious drawbacks, among which heterojunctions are the most widely used and promising strategy. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction nanomedicine, such as semiconductor-semiconductor heterojunctions (including type I, type II, type III, PN, and Z-scheme junctions) and semiconductor-metal heterojunctions (including Schottky, Ohmic, and localized surface plasmon resonance-mediated junctions). The catalytic mechanisms and properties of the above junction systems are also discussed in relation to biomedical applications, especially cancer treatment and sterilization. This review concludes with a summary of the challenges and some perspectives on future directions in this exciting and still evolving field of research.

Synthesis of Magnetic α-Fe2O3/Rutile TiO2 Hollow Spheres for Visible-Light Photocatalytic Activity

The high recombination rate of the electron-hole pair on the surface of rutile TiO2 (RT) reduces its photocatalytic performance, although it has high thermodynamic stability and few internal grain defects. Therefore, it is necessary for RT to develop effective methods to reduce electron-hole pair recombination. In this study, magnetic α-Fe2O3/Rutile TiO2 self-assembled hollow spheres were fabricated via a facile hydrothermal reaction and template-free method. Based on the experimental result, phosphate concentration was found to play a crucial role in controlling the shape of these hollow α-Fe2O3/RT nanospheres, and the optimal concentration is 0.025 mM. Due to a heterojunction between α-Fe2O3 and RT, the electron-hole pair recombination rate was reduced, the as-synthesized hollow α-Fe2O3/RT nanospheres exhibited excellent photocatalysis in rhodamine B (RhB) photodegradation compared to α-Fe2O3 and RT under visible-light irradiation, and the degradation rate was about 16% (RT), 60% (α-Fe2O3), and 93% (α-Fe2O3/RT) after 100 min. Moreover, α-Fe2O3/RT showed paramagnetism and can be recycled to avoid secondary environmental pollution.

Synthesis and Characterization of p-n Junction Ternary Mixed Oxides for Photocatalytic Coprocessing of CO2 and H2O

In the present paper, we report the synthesis and characterization of both binary (Cu2O, Fe2O3, and In2O3) and ternary (Cu2O-Fe2O3 and Cu2O-In2O3) transition metal mixed-oxides that may find application as photocatalysts for solar driven CO2 conversion into energy rich species. Two different preparation techniques (High Energy Milling (HEM) and Co-Precipitation (CP)) are compared and materials properties are studied by means of a variety of characterization and analytical techniques UV-Visible Diffuse Reflectance Spectroscopy (UV-VIS DRS), X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Energy Dispersive X-Ray spectrometry (EDX). Appropriate data elaboration methods are used to extract materials bandgap for Cu2O@Fe2O3 and Cu2O@In2O3 prepared by HEM and CP, and foresee whether the newly prepared semiconductor mixed oxides pairs are useful for application in CO2-H2O coprocessing. The experimental results show that the synthetic technique influences the photoactivity of the materials that can correctly be foreseen on the basis of bandgap experimentally derived. Of the mixed oxides prepared and described in this work, only Cu2O@In2O3 shows positive results in CO2-H2O photo-co-processing. Preliminary results show that the composition and synthetic methodologies of mixed-oxides, the reactor geometry, the way of dispersing the photocatalyst sample, play a key role in the light driven reaction of CO2–H2O. This work is a rare case of full characterization of photo-materials, using UV-Visible DRS, XPS, XRD, TEM, EDX for the surface and bulk analytical characterization. Surface composition may not be the same of the bulk composition and plays a key role in photocatalysts behavior. We show that a full material knowledge is necessary for the correct forecast of their photocatalytic behavior, inferred from experimentally determined bandgaps.

Enhanced photocatalytic water splitting of a SILAR deposited α-Fe2O3 film on TiO2 nanoparticles

We have investigated the effect of deposition of a α-Fe2O3 thin layer on a substrate of TiO2 nanoparticles for photoelectrochemical (PEC) water splitting. The TiO2 layer was coated on an FTO substrate using the paste of TiO2 nanoparticles. The α-Fe2O3 layer was deposited on the TiO2 thin film, using the method of Successive Ionic Layer Adsorption and Reaction (SILAR) with different cycles. Various characterizations including XRD, EDX and FE-SEM confirm the formation of α-Fe2O3 and TiO2 nanoparticles on the electrode. The UV-visible absorption spectrum confirms a remarkable enhancement of the absorption of the α-Fe2O3/TiO2/FTO composite relative to the bare TiO2/FTO. In addition, the photocurrents of the composite samples are remarkably higher than the bare TiO2/FTO. This is mainly due to the low band gap of α-Fe2O3, which extends the absorption spectrum of the α-Fe2O3/TiO2 composite toward the visible region. In addition, the impedance spectroscopy analysis shows that the recombination rate of the charge carriers in the α-Fe2O3/TiO2 is lower than that for the bare TiO2. The best PEC performance of the α-Fe2O3/TiO2 sample was achieved by the sample of 70 cycles of α-Fe2O3 deposition with about 7.5 times higher photocurrent relative to the bare TiO2.

Evaluation of photoassisted treatments for norfloxacin removal in water using mesoporous Fe2O3-TiO2 materials

We report the synthesis of mesoporous TiO₂ and mesoporous Fe₂O₃-TiO₂ catalysts by using a structure-directing-surfactant method, their characterization and their employment as photocatalysts for norfloxacin degradation in aqueous solution. The main findings show that in the presence of both O₂ and H₂O₂, Fe-containing mesoporous titania (Fe₂O₃-TiO₂), with iron percentages between 1 and 3 wt%, exhibited norfloxacin degradation rates more than 60% greater than otherwise identical mesoporous titania without iron. Furthermore, the activity of the mesoporous composite catalysts also exceeds that of titania when illuminated with 405 nm light-emitting diodes. Iron loading improved the photocatalytic activity for norfloxacin degradation with values of apparent reaction rate constants of 0.037 min^-1 and 0.076 min^-1 with 1 and 3 surface wt.% of iron, respectively. An optimum of activity was found with the 3 wt% Fe₂O₃-TiO₂ catalyst. Under these conditions, 10 mg/L of norfloxacin is reacted essentially to completion and 90% of total organic carbon conversion was obtained within 120 min of reaction. This higher organic carbon conversion degree was reached due to the photo-oxidation of short-chain organic acids. The high activity of the as-synthesized mesoporous composites is attributed to the additional iron phase which led to the different reactions for H₂O₂ decomposition, but also due to the improvement in light absorbance. Finally, the activity of the most active catalyst was found to be stable over multiple sequential runs, which was related to a negligible amount of iron leaching (<0.1%) from these materials.

Bismuth Vanadate with Electrostatically Anchored 3D Carbon Nitride Nano-networks as Efficient Photoanodes for Water Oxidation

In this study, we report a photoanode consisting of a polymeric/inorganic nanojunction between novel nanostructured 3D C₃ N₄ nano-networks and BiVO₄ substrate. This nanojunction is formed such that 3D C₃ N₄ nano-networks with a positively charged surface are efficiently anchored on the BiVO₄ photoanode with a negatively charged surface. This electrostatic self-assembly can initiate and contribute to an intimate contact at the interfaces, leading to an enhanced photoelectrochemical activity and stability compared with that fabricated by non-electrostatic assembly. The C₃ N₄ nano-network/BiVO₄ photoanode achieved a remarkable photocurrent density of 4.87 mA cm^-2 for water oxidation at 1.23 V (vs. reversible hydrogen electrode) after depositing FeOOH/NiOOH as oxygen-evolution co-catalyst, which is among the highest photocurrent densities reported so far for BiVO₄ -based photoanodes.

Synthesis of a single-crystal Fe2O3 nanowire array based on stress-induced atomic diffusion used for solar water splitting

In this study, we successfully fabricated a single-crystal Fe₂O₃ nanowire array based on stress-induced atomic diffusion and used this array as the photoelectrode for solar water splitting. With the surface polishing treatment on the sample surface, the density of the Fe₂O₃ nanowire array reached up to 28.75 wire µm^-2 when heated for 90 min at 600°C. The photocurrent density of the optimized sample was 0.9 mA cm^-2 at 1.23 V versus a reversible hydrogen electrode in a three-electrode system under AM 1.5 G illumination. The incident photon-to-electron conversion efficiency was 6.8% at 400 nm.

Shape Controlled Synthesis of Copper Vanadate Platelet Nanostructures, Their Optical Band Edges, and Solar-Driven Water Splitting Properties

We report the morphological and size tailored rational and facile synthesis of copper vanadate nanostructures via sonication assisted sol gel method. Field emission scanning electron microscopy (FESEM), indicated irregular and nanoflakes morphologies for the as synthesized copper vanadate (CV-120) and copper vanadate calcined at 250 °C (CV-250). The semispherical platelets shaped morphology revealed for the copper vanadate calcined at 550 °C (CV-500). The XRD patterns confirm the monoclinic and triclinic crystal phases for CV-250 and CV-500, respectively. The optical properties of CV-250 and CV-500 via UV-DRS showed significant absorption in the visible regime at λ = 565 nm and 670 nm with band gap 2.2 eV and 1.84 eV, respectively as calculated from Kubelka-Munk (KM) equation via Tauc’s plot. The values of band edge positions of CV-250 and CV-550 straddle with the hydrogen (HER) and oxygen evolution reaction (OER) potentials. The photoelectrodes of CV-250 and CV-500 fabricated by adsorption desorption method to test their photoelectrochemical (PEC) water splitting performance in the three-electrode cell. The onset photocurrent potential is observed at ~0.42 V, which reached to saturation at 1.05 V. The photocurrent density at saturation is ~0.65 mA/cm² for CV-250 and CV-500, respectively.

Enhanced Photocatalytic Fuel Denitrification over TiO2/α-Fe2O3 Nanocomposites under Visible Light Irradiation

With increasingly stringent environmental regulations, the removal of nitrogen-containing compounds (NCCs) from gasoline fuel has become a more and more important research subject. In this work, we have successfully synthesized TiO₂/α-Fe₂O₃ heterogeneous photocatalysts with different mass ratios of TiO₂ vs. α-Fe₂O₃. Taking photocatalytic denitrification of typical alkali NCCs, pyridine, in gasoline fuel under visible light irradiation (λ ≥ 420 nm) as the model reaction, the TiO₂/α-Fe₂O₃ hybrids have exhibited enhanced photocatalytic activity compared with pure TiO₂ and α-Fe₂O₃, giving a pyridine removal ratio of ∼100% after irradiation for 240 min. The improved photocatalytic performance can be attributed to the integrative effect of the enhanced light absorption intensity and more efficient separation of photogenerated electron-hole pairs. Importantly, this type of heterogeneous photocatalysts can be easily separate in the reaction medium by an external magnetic field that is very important for industrial purpose. In addition, major reaction intermediates have been identified by the liquid chromatograph-mass spectrometer (HPLC-MS) and a tentative photocatalytic denitrification mechanism has been proposed.

Using hematite for photoelectrochemical water splitting: a review of current progress and challenges

Photoelectrochemical (PEC) water splitting is a promising technology for solar hydrogen production to build a sustainable, renewable and clean energy economy. Hematite (α-Fe₂O₃) based photoanodes offer promise for such applications, due to their high chemical stability, great abundance and low cost. Despite these promising properties, progress towards the manufacture of practical water splitting devices has been limited. This review is intended to highlight recent advancements and the limitations that still hamper the full utilization of hematite electrodes in PEC water splitting systems. We review recent progress in manipulating hematite for PEC water splitting through various approaches, focused on e.g. enhancing light absorption, water oxidation kinetics, and charge carrier collection efficiency. As the morphology affects various properties, progress in morphological characterization from thicker planar films to recent ultrathin nanophotonic morphologies is also examined. Special emphasis has been given to various ultrathin films and nanophotonic structures which have not been given much attention in previous review articles.

Fabrication of Fe2TiO5/TiO2 nanoheterostructures with enhanced visible-light photocatalytic activity

In this work, we have fabricated Fe₂TiO₅/TiO₂ heterostructures hollow nanospheres with 10 nm scale shell thickness, 220 m² g⁻¹ surface area and uniform distribution. Their visible photocatalytic activities for degrading pollutant are greatly enhanced.

Efficiently enhancing the photocatalytic activity of faceted TiO2nanocrystals by selectively loading α-Fe2O3and Pt co-catalysts

The photocatalytic activity of faceted TiO₂nanocrystals was efficiently enhanced by selectively loading α-Fe₂O₃and Pt co-catalysts onto specific facets.

Dendritic α-Fe2O3/TiO2 nanocomposites with improved visible light photocatalytic activity

A branch-like α-Fe₂O₃/TiO₂ heterostructure has been synthesized controllably through an electrospinning method combined with a hydrothermal approach.

Constructing Fe2O3/TiO2 core-shell photoelectrodes for efficient photoelectrochemical water splitting

In this study, plasma enhanced chemical vapor deposition (PECVD) was utilized to co-axially modify hydrothermally grown Fe2O3 nanorod arrays by depositing a TiO2 overlayer to create Fe2O3/TiO2 core-shell photoelectrodes. Comprehensive structural (XRD, SEM, TEM) and compositional (XPS) analyses were performed to understand the effects of the TiO2 shell on the PEC activities of the Fe2O3 core. It was revealed that the heterojunction structure formed between TiO2 and Fe2O3, significantly improved the separation efficiency of photo-induced charge carriers and the oxygen evolution kinetics. A maximum photocurrent density of ∼900 μA cm(-2) at 0.6 V vs. saturated calomel electrode (SCE) was obtained for the Fe2O3/TiO2 photoelectrodes, which was 5 and 18 times higher when compared to that of hydrothermally synthesized Fe2O3 and PECVD synthesized TiO2 electrodes, respectively. Moreover, the Fe2O3/TiO2 core-shell nanorod arrays displayed superior stability for PEC water splitting. During 5000 s PEC measurements, a steady decrease of the photocurrent was observed, mainly attributed to the evolution of oxygen bubbles adsorbed on the working electrodes. This observation was verified by the complete recovery of the PEC performance demonstrated for a second 5000 s PEC measurement carried out after a brief time interval (10 min) that allowed the electrode surface to regenerate.

Plasmonic silver quantum dots coupled with hierarchical TiO2 nanotube arrays photoelectrodes for efficient visible-light photoelectrocatalytic hydrogen evolution

A plasmonic Ag/TiO₂ photocatalytic composite was designed by selecting Ag quantum dots (Ag QDs) to act as a surface plasmon resonance (SPR) photosensitizer for driving the visible-light driven photoelectrocatalytic hydrogen evolution. Vertically oriented hierarchical TiO₂ nanotube arrays (H-TiO₂-NTAs) with macroporous structure were prepared through a two-step method based on electrochemical anodization. Subsequently, Ag QDs, with tunable size (1.3-21.0 nm), could be uniformly deposited on the H-TiO₂ NTAs by current pulsing approach. The unique structure of the as-obtained photoelectrodes greatly improved the photoelectric conversion efficiency. The as-obtained Ag/H-TiO₂-NTAs exhibited strong visible-light absorption capability, high photocurrent density, and enhanced photoelectrocatalytic (PEC) activity toward photoelectrocatalytic hydrogen evolution under visible-light irradiation (λ > 420 nm). The enhancement in the photoelectric conversion efficiency and activity was ascribed to the synergistic effects of silver and the unique hierarchical structures of TiO₂ nanotube arrays, strong SPR effect, and anti-shielding effect of ultrafine Ag QDs.

ZnO-dotted porous ZnS cluster microspheres for high efficient, Pt-free photocatalytic hydrogen evolution

The Pt-free photocatalytic hydrogen evolution (PHE) has been the focus in the photocatalysis field. Here, the ZnO-dotted porous ZnS cluster microsphere (PCMS) is designed for high efficient, Pt-free PHE. The PCMS is designed through an easy "controlling competitive reaction" strategy by selecting the thiourea as S(2-) source and Zn(Ac)₂·2H₂O as Zn source in ethylene glycol medium. Under suitable conditions, one of the PCMS, named PCMS-1, with high SBET specific area of 194 m(2)g(-1), microsphere size of 100 nm and grain size of 3 nm can be obtained. The formation of PCMS is verified by TEM, XAES, XPS, Raman and IR methods. Importantly, a series of the experiments and theoretical calculation demonstrate that the dotting of ZnO not only makes the photo-generated electrons/hole separate efficiently, but also results in the formation of the active catalytic sites for PHE. As a result, the PCMS-1 shows the promising activity up to 367 μmol h(-1) under Pt-free condition. The PHE activity has no obvious change after addition 1 wt.% Pt, implying the presence of active catalytic sites for hydrogen evolution in the PCMS-1. The easy synthesis process, low preparation cost of the PCMS makes their large potential for Pt-free PHE.

Synthesis of GO supported Fe2O3–TiO2 nanocomposites for enhanced visible-light photocatalytic applications

This article reports novel ternary composites consisting of Fe₂O₃ nanorods, TiO₂ nanoparticles, and graphene oxide (GO) flakes that provide enhanced photocatalytic performance and stability.

Modification of a thin layer of α-Fe2O3 onto a largely voided TiO2 nanorod array as a photoanode to significantly improve the photoelectrochemical performance toward water oxidation

A largely voided TiO₂ nanorod array was modified with Fe₂O₃ thin layers to deliver ∼3.3 times higher the applied bias photon-to-current efficiency than that of a plain TiO₂ nanorod array.

Photo-synergistic promoted in situ generation of Bi0–BiSbO4 nanostructures as an efficient catalyst for nitrobenzene reduction

This work reports on the construction of Bi⁰–BiSbO₄ nanostructures to show photo-synergistic and efficient catalytic activity toward nitrobenzenes reduction.

Improved photoactivity of TiO2–Fe2O3 nanocomposites for visible-light water splitting after phosphate bridging and its mechanism

The phosphate bridges built are favorable for charge transfer and separation, leading to a greatly-enhanced photoactivity for water splitting.