Visible Irradiation Research Articles

Visible Light‐Driven Eosin Y‐Catalyzed Suzuki‐Type Sulfonylation

AbstractA strategy for sulfonylation of boronic acids with sulfonyl chlorides has been established via Suzuki‐type radical cross‐coupling. This approach allows for the synthesis of more than 50 sulfone examples enabled by photoredox catalysis under visible light radiation. Moreover, the title reaction is applied in late‐stage functionalization of bioactive molecules, and further transformation of the resulting sulfones into 2‐functionalized sulfones, borates, triphenylphosphine oxide and N‐arylcarbazole can be also achieved.

Effect of substituents on the performance of N-carbazolyl double benzylidene ketones in visible/NIR light one/two-photon polymerization

Developing high-performance photoinitiation systems with high sensitivity is of great significance in one/two-photon polymerization. Especially, photoinitiators with rapid photobleaching effects, deep curing abilities and potential for two-photon lithography have great commercial prospects. However, such photoinitiators often require complex organic synthesis, thus having relatively limited varieties. Double benzylidene ketone is widely used as a high-performance dye and can be constructed through a one-step classical aldol condensation reaction. The optimization of its structure often involves introducing extended conjugated structures or different terminal substituents. However, the synergistic impacts of side substituents with different electron effects are rarely studied. Here, six novel carbazolyl double benzylidene ketones with tert-butyl on the terminal position and F atom or N, N-dimethylamino groups substituted at the side position on conjugated structures are designed and prepared to explore the structure–activity relationships. Notably, results show that introducing electron-donating groups at both positions can effectively induce a redshift in the absorption spectra of molecules, and the introduction of an electron-withdrawing F atom on the side position induces impressive photobleaching during photopolymerization under visible LED irradiation. Moreover, CZs/MDEA with PETA exhibit fast writing speed and excellent nano-patterning capability under 780 nm laser in two-photon polymerization (TPP) and have potential applications in 3D microfabrication technologies.

Direct photodegradation of internally mixed sodium chloride and malonic acid single aerosols: Impact of the photoproducts on the hygroscopic properties of the particles

Sea-salt aerosols (SSA) are one of the key natural aerosols in our atmosphere, consisting predominantly of sodium chloride (NaCl). Throughout their atmospheric transport, these aerosols undergo complex internal mixing, giving rise to a rich variety of inorganic and organic species, including dicarboxylic acids. This study investigates firstly the composition and deliquescence properties of coarse particles containing pure malonic acid (MA2, CH2(COOH)2) and internally mixed NaCl and MA2, by means of an acoustic levitation system coupled with a Raman microspectrometer. Secondly, we report here the first experimental observation and characterization of the products arising from photochemical reactions under UV–Visible irradiation (338 ≤ λ ≤ 414 nm) in the absence of an oxidant under acoustic levitation conditions in MA2 and NaCl/MA2 aerosols. Furthermore, the impact of photodegradation on the hygroscopic properties of these particles is examined. We confirmed the irreversible formation of monosodium malonate (NaMA, HOOCCH2COONa), which coexists with NaCl or MA2 on non-irradiated particles. We also demonstrated the formation of oxalic acid (OA2, HOOC–COOH) within irradiated MA2 droplets and the appearance of glyoxylic acid (GlyA, HCOCOOH) in NaCl containing droplets. The photolysis process exerts a marked effect on the hygroscopic properties of the particles, resulting in a shift in deliquescence transitions toward higher relative humidity (RH) values. This study contributes to the understanding of the intricate physicochemical processes involved in SSA during their atmospheric transport. Likewise, this work sheds light on the impacts of these types of aerosols on cloud formation and climate change.

Stability of monomeric indigo in the electronic ground state: An experimental matrix isolation infrared and theoretical study

Monomers of indigo were investigated using experimental (matrix-isolation) and theoretical methods. For the first time, the infrared spectrum of indigo molecules isolated in low-temperature Ar matrices was recorded and subjected to a detailed theoretical analysis. An excellent agreement between the experimental spectrum of indigo monomers and the spectrum theoretically predicted for the highly-symmetric (C2h) most stable dioxo form of the compound allowed a very reliable assignment of the observed infrared absorption bands. Matrix-isolated monomers of indigo were exposed to UV–vis radiation of different wavelengths. The conducted experiments demonstrated that molecules of indigo do not undergo any structural changes, even under irradiation with short-wavelength UV (λ > 200 nm) light. Theoretical calculations concerning the stability of photoproducts that could be potentially generated from indigo were conducted. The calculations carried out for the species generated by hydrogen-atom transfer from N1′ to O atom attached to the opposite ring revealed that both the oxo-hydroxy and dihydroxy tautomers of indigo should be unstable in the ground electronic state. The calculations carried out for the C2H tautomer (which may be generated by a hydrogen atom shift from N1′ to C2 of the opposite ring) led to optimization of the structure that is potentially stable, but very much distorted from planarity.

Electrochemical analysis of thermally treated two dimensional zinc sulphide hexagonal nano-sheets with reduced band gap

Significantly reduced band gap (2.0 eV) zinc sulphide (ZnS) nanoparticles are synthesized using microwave/ultraviolet/ultrasonic assisted hydrothermal route in a two step process. Initially, ZnS nanospheres are synthesized, showing a cubic structural phase with a band gap of 3.2 eV, which is further annealed at 1000 °C to get the final product. Following annealing, the cubic ZnS undergoes a phase change to wurtzite ZnS, in the form of hexagonal nanosheets showing polymorphism phenomena, along with a reduced band gap of 2 eV. The optical analysis reveals a red shift in the absorbance region, transitioning from the absorption of UV radiations in cubic ZnS to visible radiations in wurtzite ZnS. Thermogravimetric (TGA) measurements and its analysis also revealed the phase change of ZnS (cubic) to ZnS (Wurtzite) when heated at 1000 °C. Microstructural analysis reveals the formation of sheets oriented along (100) plane, which is evidenced by the interplanar spacing and lattice fringes. The photoluminscence spectra highlights quantum energy states present between the highest occupied molecular orbital (HOMO), which is 2.36 eV for cubic phase and 1.76 eV for the hexagonal phase, and the lowest unoccupied molecular orbital (LUMO), with values of −0.84 eV for cubic while −0.24 for hexagonal ZnS. The CIE coordinates for wurtzite ZnS, at X= 0.55 and Y= 0.23, corresponds to red light emission. The suitability of wurtzite phase ZnS for solar cell applications has been demonstrated through electrochemical studies using Nyquist plot and cyclic voltrammetry (CV) techniques. CV demonstrates the presence of redox peaks and reversibility of the material during the redox process. The diffusive behaviour is also confirmed by observing the variation of peak current with scan rate, following Rendle Sevick equation. The presence of Warburg diffusion in Nyquist plot indicates the efficient charge transfer dynamics of the material, suggesting a high potential for exciton formation in energy production. Consequently, this material stands as a promising candidate for efficient solar cells.

Photochromic ceramics for multimode detection of UV-VIS radiation dose

Electromagnetic radiation in the ultraviolet-to-visible (UV-VIS) band is closely related to human life, and therefore, accurate measurement of UV-VIS radiation dose is essential. However, there are disadvantages to existing radiation dose equipment: it is cumbersome to operate, takes time to analyze, and lacks multimodal measurements. In this study, a photochromic ceramic with rare earth ions Ho3+ and Yb3+ co-doped Ca2SnO4 host was developed. It produces rapid color switching between light yellow and black under UV and VIS radiation. The XPS and EPR results indicate that oxygen vacancies are important in coloring. Based on the photochromic effect, the intensity of down and up-conversion luminescence can be regulated. The maximum regulation rate is 95 %, higher than most photochromic materials of the same type. A multimode UV-VIS radiation detection method is proposed based on photochromism, down-conversion, and up-conversion luminescence light intensity modulation. The results show that the ceramics respond to a wide spectral range of electromagnetic radiation from UV-VIS with varying degrees, and the best response is to UVB (Ultraviolet Radiation B). A convenient scheme for on-site radiation dosimetry by colorimetry and changes in luminescence intensity was designed to verify the method's reliability. Stability tests have shown that these ceramics have good cyclic stability, making them an ideal detection material for accurate UV-VIS radiation dose detection.

Hybrid CdSe/ZnS Quantum Dot-Gold Nanoparticle Composites Assembled by Click Chemistry: Toward Affordable and Efficient Redox Photocatalysts Working with Visible Light.

A new modular, easy-to-synthesize photocatalyst was prepared by assembling colloidal CdSe/ZnS quantum dots (QD) and gold nanoparticles (AuNP) via their ligands thanks to copper-catalyzed azide to alkyne cycloaddition (CuAAC) click chemistry. The resulting composite (QD-AuNP) photocatalyst was tested with a benchmark photoredox system previously reported by our group, for which QD alone acted as a photocatalyst but with a modest quantum yield (QY = 0.06%) and turnover number (TON = 350 in 3 h) due to poor charge separation. After optimization, the QD-AuNP composites exhibited much improved photocatalytic performances: up to five times higher TON (2600 in 3 h) and up to 24 times faster reaction in the first 10 min of visible irradiation. Such an improvement is attributed to an efficient electron transfer from QD to AuNP in the photoexcited QD-AuNP composites, which ensures a much better charge separation than that in QD alone. This was confirmed by studying both (i) the quenching of the QD photoluminescence during the synthesis of the QD-AuNP composites and (ii) the blue shift of the AuNP plasmon absorption band due to the accumulation of up to 7400 electrons per AuNP in QD-AuNP composites under visible light irradiation in the presence of electron donors.

Growth of Ag2S-sensitizer on MoS2/ZnO nanocable arrays for improved solar driven photoelectrochemical water splitting

The demonstration of an efficient nanostructure that provides acceptable photoelectrochemical water splitting properties using the sun visible radiation is an appealing issue. In this connection, a new ternary nanocomposite of Ag2S/MoS2/ZnO photoanode is subsequently fabricated via hydrothermal, solvothermal and SILAR methods. Different properties of the nanocomposite are characterized by XRD, SEM, EDX, XPS, UV–Vis-IR spectroscopy and electrochemical techniques. The post-grown annealed 8-Ag2S/MoS2/ZnO photoanode exhibits a good performance with a photocurrent density of 2 mA/cm2 at a bias potential 1.23 V vs. RHE. The photocurrent of the post-grown annealed 8-Ag2S/MoS2/ZnO photoanode is 71.42 times, 40 times and 2 times higher compares to the pure ZnO, post-grown annealed MoS2/ZnO, and post-grown annealed 8-Ag2S/ZnO photoanodes, respectively. The enhanced PEC performance may originate from the combination of different effects such as the expansion of light absorption and energy band alignment (type II heterostructures), [SO4] acted as a charge-transfer medium, and electrode-electrolyte interface kinetic reactions.

The comparative effects of visible light and UV-A radiation on the combined toxicity of P25 TiO2 nanoparticles and polystyrene microplastics on Chlorella sp.

The ubiquitous presence of TiO2 nanoparticles (nTiO2) and microplastics (MPs) in marine ecosystems has raised serious concerns about their combined impact on marine biota. This study investigated the combined toxic effect of nTiO2 (1 mg/L) and NH2 and COOH surface functionalized polystyrene MPs (PSMPs) (2.5 and 10 mg/L) on Chlorella sp. All the experiments were carried out under both visible light and UV-A radiation conditions to elucidate the impact of light on the combined toxicity of these pollutants. Growth inhibition results indicated that pristine nTiO2 exhibited a more toxic effect (38%) under UV-A radiation when compared to visible light conditions (27%). However, no significant change in the growth inhibitory effects of pristine PSMPs was observed between visible light and UVA radiation conditions. The combined pollutants (nTiO2 + 10 mg/L PSMPs) under UV-A radiation exhibited more growth inhibition (nTiO2 + NH2 PSMPs 66%; nTiO2 + COOH PSMPs 50%) than under visible light conditions (nTiO2 + NH2 PSMPs 55%; TiO2 + COOH PSMPs 44%). Independent action modeling indicated that the mixture of nTiO2 with PSMPs (10 mg/L) exhibited an additive effect on the algal growth inhibition under both the light conditions. The photoactive nTiO2 promoted increased production of reactive oxygen species under UV-A exposure, resulting in cellular damage, lipid peroxidation, and impaired photosynthesis. The effects were more pronounced in case of the mixtures where PSMPs added to the oxidative stress. The toxic effects of the binary mixtures of nTiO2 and PSMPs were further confirmed through the field emission electron microscopy, revealing specific morphological abnormalities. This study provides valuable insights into the potential risks associated with the combination of nTiO2 and MPs in marine environments, considering the influence of environmentally relevant light conditions and the test medium.

Superior functionality of niobium pentoxide nano-rod/tripod photocatalyst synthesized using polyethyleneimine as a soft template for the abatement of methylene blue under UV and visible irradiation.

Polyethyleneimine (PEI) capping agent-cum-template-mediated synthesis of niobium oxide nanoparticles is reported to explore its impact on the resultant morphology, porosity, crystallinity, phase complexation, and thus on the photocatalytic activity. The resultant niobium oxides calcined at 800°C and 1000°C crystallized into highly ordered nano-rod/tripod nanostructure with inter-rod angle <120° having orthorhombic phase and heavily agglomerated rod-like nanostructures having monoclinic crystal phase, respectively. Contrary to the expectations, the nano-rod/tripods showed superior photocatalytic degradation kinetics and high adsorption of methylene blue dye in the hydrocolloid than formerly reported monoclinic nanoparticles. The best adsorption capability and photocatalytic activity are observed for the sample calcined at 800°C, resulting in a combined degradation efficiency of 98.8% of methylene blue dye. The adsorption characteristics, stability of the hydrocolloid system, the existence of oxygen vacancies, and the distinct morphology of the photocatalytic nano-rod/tripods are mainly responsible for this behavior. The process and the performance of unique nanostructure over others presents a superior alternative.

Engineering the nanostructure of iron-doped ZnO for the construction of Fe-ZnO/SGCN nanocomposites to enhance the spatial charge separation and their potential applications

In this study, it is targeted to manufacture iron doped zinc oxide (Fe-ZnO) composite with sulphur doped graphitic carbon nitride (SGCN) in two steps using the sol–gel methodology. Initially, Fe (0.5, 1, 2, 4, 6, 8, and 10 wt%) was incorporated into ZnO nanostructure and its photocatalytic characteristics were examined against contaminant dye (methylene blue). 2% Fe-ZnO nanoparticles (NPs) showcased the best photocatalytic activity by degrading methylene blue (MB) dye completely under visible radiation, therefore it was opted for designing composites with SGCN. In the 1st step, SGCN was synthesized through thermal degradation of thiourea. In the 2nd step, 2% Fe-ZnO /SGCN heterostructure composite photocatalysts were prepared by incorporating 2% Fe-ZnO NPs with variable SGCN contents (i.e., 25, 50 & 75 wt%). The fabricated 2% Fe-ZnO/50% SGCN nanocomposite outperforms ZnOand other 2% Fe-ZnO/SGCN (25 & 75 wt%) nanocomposites (NCs) with respect to photocatalytic performance.

Design, analysis and validation of Customised Homocentric Fresnel Collector based on longest wavelength of visible spectrum

The paper presents the design of a Customised Homocentric Fresnel Collector (CHFC) based on the principle of superposition and the longest wavelength of the visible spectrum. A bottom-to-top approach is proposed that uses an individually designed homocentric prism based on visible light at a wavelength of 740 nm. The homocentric prism of the CHFC follows a uniform height method with varying pitch. An area focus is achieved on the plastic optical fibre (POF) bundle inlet without employing any secondary optical element. The CHFC achieves a uniform distribution of concentrated visible spectrum radiation from the Sun with a significant reduction in the hotspot problem. Comparison of the CHFC versus a mid-wavelength-based Fresnel lens shows that the CHFC delivers 9.24% more visible spectrum radiation on the POF bundle inlet. The simulated optical efficiency of the CHFC is 90.6%. Numerical analysis of a CHFC-based daylighting system shows that 331 lm (efficiency of 39.4%) can be delivered via a 10 m long fibre bundle made up of 32 POF each of 1 mm diameter. Experimental observations demonstrated that the maximum temperature recorded on the POF bundle entrance is 56.8°C during peak direct normal illuminance conditions. Note that the spectral distribution of the radiation emerging from the POF differs from the incident sunlight spectrum because of the transmission characteristics of the optical components used in the CHFC testbed.

Synthesis of malonic acid-VTiO2 photocatalysts for the photodegradation of micropollutant

Herein, a novel malonic acid-vanadium doped TiO2 (m-VTiO2) photocatalysts with different V ratios were synthesized via crosslinking and hydrothermal treatment. Malonic acid was employed as the cross-linking agent to chemically bind TiO2 and vanadium via its dicarboxylic functional group. The synthesized m-VTiO2 photocatalyst presents a large surface area with sheet-like morphology. XPS results revealed the existence of vanadium in the V5+ and V4+ states, and the binding energies of Ti-O bonds were changed significantly with the introduction of vanadium. The photocatalytic activity increased gradually with the vanadium content and decreased when it attained the maximum value at 7.5% m-VTiO2 for sulfamethoxazole (SMX). The optimal photocatalyst (m-TV3) presents the best photocatalytic activity for SMX owing to its improved surface area. The reaction rate of 7.5 % m-VTiO2 was 4.86-fold higher than that of the un-doped TiO2 particle under visible irradiation. The photodegradation efficiency of SMX was still up to 86.07 % after six cycling runs, indicating the good reusability of the photocatalyst. More importantly, the photocatalysts also show high photocatalytic activity for RHB dye. In addition, a potential mechanism for enhancing the photocatalytic activity under visible irradiation was put forth.

Construction of Novel Z-scheme Heterojunction in ZnFe2O4/P25 @ MOF-5 Nanocomposite from Plastic Waste for Efficient Photodegradation of Aqueous BTX Under Visible Light

AbstractAn innovative strategy to reduce water pollution is adsorption-assisted photocatalysis. A novel mesoporous heterogeneous adsorbent MOF-5-based photocatalysts were successfully synthesized by a green method from plastic waste through a one-step solvothermal process. Additionally, ZnFe2O4 nanocrystals were physically ground with commercial Degussa P25 at room temperature to prepare ZF/P nanocomposite catalysts. These catalysts demonstrated significant photocatalytic activity for the removal of BTX from wastewater. BTX was successfully degraded in an aqueous solution utilizing integrated adsorption and photocatalytic degradation using the newly developed ZF/P@MOF-5 samples with 0.01% of ZF/P. The in-depth characterization of the ZF/P@MOF-5 confirmed its positive physicochemical properties, such as porous nature, stability, high surface area, beneficial functional groups on its surface, and photocatalytic activity. PL spectroscopy also shows that the ZF/P-incorporated MOF-5 nanocomposite has a lower electron-hole recombination rate. The as-prepared ZF/P@MOF-5 mesoporous heterogeneous adsorbent-photocatalyst presented high adsorption and maximum degradation of BTX under visible radiations after 180 min. The reusability results demonstrated that 20 P/ZF @MOF-5 composite can be used effectively for up to four cycles, which makes the process more economical. This experimental study demonstrates that the novel ZF/P-incorporated MOF-5 is a potential route to producing photocatalysts for dissociating BTX wastewater that is highly effective, stable, economical, and sustainable.

Keratinocytes Exposed to Blue or Red Light: Proteomic Characterization Showed Cytoplasmic Thioredoxin Reductase 1 and Aldo-Keto Reductase Family 1 Member C3 Triggered Expression.

Several cell-signaling mechanisms are activated by visible light radiation in human keratinocytes, but the key regulatory proteins involved in this specific cellular response have not yet been identified. Human keratinocytes (HaCaT cells) were exposed to blue or red light at low or high irradiance for 3 days in cycles of 12 h of light and 12 h of dark. The cell viability, apoptotic rate and cell cycle progression were analyzed in all experimental conditions. The proteomic profile, oxidative stress and mitochondrial morphology were additionally evaluated in the HaCaT cells following exposure to high-irradiance blue or red light. Low-irradiance blue or red light exposure did not show an alteration in the cell viability, cell death or cell cycle progression. High-irradiance blue or red light reduced the cell viability, induced cell death and cell cycle G2/M arrest, increased the reactive oxygen species (ROS) and altered the mitochondrial density and morphology. The proteomic profile revealed a pivotal role of Cytoplasmic thioredoxin reductase 1 (TXNRD1) and Aldo-keto reductase family 1 member C3 (AKR1C3) in the response of the HaCaT cells to high-irradiance blue or red light exposure. Blue or red light exposure affected the viability of keratinocytes, activating a specific oxidative stress response and inducing mitochondrial dysfunction. Our results can help to address the targets for the therapeutic use of light and to develop adequate preventive strategies for skin damage. This in vitro study supports further in vivo investigations of the biological effects of light on human keratinocytes.

Nanocrystalline Co/Ga substituted CuFe2O4 magnetic nanoferrites for green hydrogen generation

The research study on the design of cobalt and gallium substituted copper nanoferrites through sol-gel auto-combustion were testify to check the photocatalytic/electrocatalytic water splitting efficiency of prepared nanoferrites for hydrogen generation. XRD study confirms the formation tetragonal phase for all fabricated nanoferrites with no additional phases of impurities. The tetragonal shaped grains with definite grain boundaries were observed from the FESEM study. The magnetic measurements show large hysteresis loop area with high magnetization of 58.45 emu/g for undoped copper nanoferrite. The catalytic behaviors of the fabricated nanocatalysts for the photo-catalytic H2 production was determined by using 0.079 M Na2SO3 and 0.128 M Na2S as the sacrificial agents, that give electron donor site during photo-catalysis under UV–visible irradiation. As compared to other compositions, Cu0.99Co0.01Ga0.01Fe1.99O4 (x = y = 0.01) nano photocatalyst attained the highest photocatalytic activity of 18.11 mmol gcat−1. Also, the as-synthesized photocatalysts repeatability and stability were evaluated throughout repeated runs of 4 h reaction period conducted under identical circumstances. However, all electrocatalytic analysis for hydrogen evolution reaction (HER) activity were performed using three electrode arrangements (reference, counter, and working electrodes) in 0.5 M H2SO4 electrolyte mixture. There was a rise in overpotential at 10 mA/cm−2 cathode current density as concentrations of Co/Ga for the synthesized nanoferrites were increased. It has been showed that CuFe2O4 had a high electrocatalytic HER activity. In addition, the produced nanoferrites were also examined against different type of bacterial strains, where Cu0.99Co0.01Ga0.01Fe1.99O4 indicated maximum zone of inhibition (ZOI) against Bacillus subtilis (20 ± 0.55 mm), Salmonella typhi (12 ± 0.52 mm), Escherichia coli (16 ± 0.49 mm), and Staphylococcus aureus (12 ± 0.54 mm), respectively. Hence, with these efficient overall photocatalytic and electrocatalytic water splitting traits, the prepared nanoferrites are highly useful for the green hydrogen production applications.

Visible-Light-Active BiOI/TiO2 Heterojunction Photocatalysts for Remediation of Crude Oil-Contaminated Water.

In this study, BiOI-sensitized TiO2 (BiOI/TiO2) nanocomposites with different levels of BiOI deposited via sequential ionic layer adsorption and reaction (SILAR) have been explored for the degradation of methyl orange, 4-chlorophenol (4-CP), and crude oil in water under visible (>400 nm) irradiation with excellent degradation performance. The reaction progress for methyl orange and 4-chlorophenol was monitored by a UV-vis spectrophotometer, and the degradation of the crude oil hydrocarbons was determined by GC-MS. The BiOI/TiO2 heterojunction improves separation of photogenerated charges, which enhances the degradation efficiency. Evaluation of the visible-light photocatalytic performance of the synthesized catalysts against methyl orange degradation confirmed that four SILAR cycles are the optimal deposition condition for the best degradation efficiency. The efficiency was further confirmed by degrading 4-CP and crude oil, achieving 38.30 and 85.62% degradation, respectively, compared with 0.0% (4-CP) and 70.56% (crude oil) achieved by TiO2. The efficiency of TiO2 in degrading crude oil was mainly due to adsorption along with photolysis. This study provides a simple and cost-effective alternative to traditional remediation methods requiring high energy consumption for remediation of crude oil-polluted water and refinery wastewater using visible-light photocatalysis along with adsorption.

Visible light induced self‐cleaning performance of iron‐doped TiO2 nanoparticles for surface applications

AbstractThis study aimed to enhance the visible light photosensitivity of TiO2 nanoparticles for self‐cleaning applications by doping with Fe3+. Nanocrystalline undoped and Fe‐doped TiO2 (Ti1 − xFexO2, x = .01–.04) were synthesized via sol–gel method. The results demonstrated that Fe‐doped TiO2 nanoparticles exhibited visible light sensitivity and self‐cleaning properties. An increased Fe concentration resulted in a red shift in the absorption band edge. Fe0.03‐doped TiO2 with an average particle size of ∼21 nm, a crystallite size of ∼12 nm, and a band gap of ∼2.86 eV showed the highest photocatalytic activity (60% methylene blue degradation) and super‐hydrophilicity (water droplet contact angle 9°) under visible light radiation. These findings highlight the potential of Fe‐doped TiO2 nanoparticles as a promising material for self‐cleaning applications.

Room Temperature Exsolution of Cds Nanodots on A‐site Deficient Cotton‐Ball Like Titanate Perovskite Nanoparticles for H2 Production Under Visible Light

AbstractExsolution of nanoparticles followed by chemical treatment (“chemistry at a point”) is a very exciting approach to the smart design of functional materials such as visible light active photocatalysts. Unfortunately, the usually utilized thermal reduction approach is not feasible for low melting point metals and compounds such as Cd and CdO. Here a hydrothermal approach to prepare exsolved CdS nanodots on cotton ball‐like perovskite supports is described. The titanate‐based photocatalyst is synthesized using a hydrothermal process followed by room‐temperature sulfidation. The hydrothermal route directs A‐site doping of Cd2+ via hydroxyl group incorporation in the titanate lattice. Formation of CdS via exsolution provides a high H2 production mass activity of 3050 µmol g−1 h−1 under visible light with only 5 mol.% Cd doping of the titanate. Moreover, the strong CdS‐support interaction offers good cycling stability under UV–vis and visible light irradiation. This is the first report describing the exsolution of CdS nanodots at room temperature and shows its advantages for photocatalytic activity.

Unveiling the synergistic interplay of appropriate oxygen vacancies and S-scheme heterojunction structures in OVs-TiO2/g-C3N4 catalyst for efficient RhB photodegradation and H2 production

This study presents a facile synthesis for an efficient S-scheme OVs-TiO2/g-C3N4 heterojunction (OVs-TCN) enriched with oxygen vacancies, demonstrating exceptional performance in photocatalytic RhB degradation and H2 production. Controlled introduction of g-C3N4 into OVs-TiO2 modulates appropriate oxygen vacancies within the OVs-TCN10 heterojunction. Under visible irradiation, OVs-TCN10 achieves a remarkable 97.2 % degradation of RhB over 120 min with 5 cycles, with an apparent rate constant of 0.021 min−1. Impressively, OVs-TCN10 exhibits significant H2 production from RhB degradation, reaching a rate of 150 µmol h−1 under visible irradiation for 30 h, with a 15 % AQY at 420 nm. Experimental and DFT analyses of charge density difference, along with Mulliken analysis at the OVs-TiO2/g-C3N4 interface, confirm the existence of an intrinsic electric field flowing from g-C3N4 to OVs-TiO2. This internal electric field enhances photogenerated electron-hole separation and transfer, facilitating the redox process via the S-scheme mechanism in the heterojunction for photocatalytic RhB degradation and H2 production. This work offers new insights into the controlled defects and interfacial mechanisms in heterojunctions, propelling advanced photocatalytic applications.