Simulated Sunlight Irradiation Research Articles

Photoinduced oxidation of chromium picolinate to hexavalent chromium in the presence of ferric ions

The occurrence of chromium picolinate (Cr(pic)3) in environment has attracted raising concerns on its fate and the associated risks. Herein, the photoinduced oxidation of Cr(pic)3 in the presence of ferric ions (Fe(III)) under simulated sunlight and natural solar light irradiation were investigated. Cr(pic)3 was stable under dark or without Fe(III). 87.9 % of Cr(pic)3 (C0 = 1.0 μM) was degraded in the presence of 50 μM Fe(III) after 90 min simulated sunlight irradiation at initial pH of 4.0. •OH was the main cause for Cr(pic)3 oxidation, it attacked the chromium center to generate hexavalent chromium (Cr(VI)) and picolinic acid (k = 5.9 ×108 M−1·s−1). Picolinic acid could be further oxidized to NH4+ and small organics. Relative higher Fe(III) content (25 – 75 μM) and Cr(pic)3 concentration (0.5 – 2.0 μM) promoted both of Cr(pic)3 degradation and Cr(VI) accumulation. While, the degradation of Cr(pic)3 decreased with pH at the range of 3.0 – 8.0, more Cr(VI) was accumulated at pH 5.0 and 6.0. The co-existence of inorganic ions and dissolved organic matter (DOM) in river water inhibited Cr(pic)3 oxidation by scavenging the •OH formed and shielding the light. 8.0 – 16.7 μg/L of Cr(VI) was accumulated after 9.0 h simulated sunlight irradiation of Cr(pic)3 in river water matrix ([Fe(III)]0 = 50 – 100 μM). The generation of Cr(VI) under solar light was slower than that under simulated sunlight due to the weaker light intensity (43.2 – 85.0 mW/cm2 vs. 750 – 1300 mW/cm2). These results consistently suggest photoinduced oxidation of Cr(pic)3 in environment generates the toxic Cr(VI), which deserves significant attention.

Photocatalytic Degradation of Carbofuran in Water Using Laser-Treated TiO2: Parameters Influence Study, Cyto- and Phytotoxicity Assessment.

This study investigates the impact of changing parameters on the photocatalytic degradation of carbofuran (CBF) using laser-treated TiO2 nanotube arrays on a Ti mesh under simulated sunlight irradiation and assessing toxicity during photocatalytic degradation. Various parameters, including the stirring effect, light intensity, initial CBF concentration, and variation in the active surface area of laser-treated TiO2 photocatalysts, were examined to determine their impact on degradation efficiency. The photodegradation kinetics were monitored using ultra-performance liquid chromatography with a PDA detector (UPLC-PDA) and UV-Vis spectrophotometry, while mineralization was assessed by a total organic carbon (TOC) analyzer. The photocatalytic degradation of CBF is enhanced by an increase in the active surface area of the TiO2 photocatalyst, light intensity, and the introduction of stirring, but it decreases with an increase in the initial concentration of CBF. The toxicity assessments revealed that the cytotoxicity of CBF initially increased during the degradation process but decreased after further treatment, indicating the formation and subsequent breakdown of toxic intermediates. The phytotoxicity test showed that longer degradation times resulted in higher toxicity to plant growth. This study provides new insights into the photocatalytic degradation of CBF with TiO2, the importance of parameter optimization for more efficient treatment, and the use of toxicity tests to confirm the success of the photocatalytic process.

Enhanced photocatalytic degradation of polylactide (PLA) through TiO2-based up-conversion nanoparticles

As a degradable polymer material, the regulation of the degradation rate of polylactide (PLA) under an actual light exposure environment is of significant importance for realizing its multifaceted applications. This study aims to enhance the photodegradation of PLA under irradiation with lower-energy wavelengths by using TiO2-based up-conversion nanoparticles (UCNPs). Two modification methods were employed: doping TiO2 with Yb3+/Er3+/Tm3+ ions integrated within the TiO2 lattice, and creating a composite photocatalyst by adhering Y2O3: Yb3+/Er3+/Tm3+ to the exterior of TiO2 grains. The study investigated the impact of these two different TiO2-based UCNPs on the photocatalytic degradation rate and mechanism of PLA under simulated sunlight irradiation. Research has found that the doped TiO2, due to its narrower bandgap and higher photon utilization efficiency during the up-conversion process, exhibited superior catalytic efficiency in catalyzing the photodegradation reactions of PLA compared to unmodified TiO2 and composite TiO2. This work proposes a novel strategy for preparing PLA composites with enhanced photodegradation speed provided by modified TiO2, efficient light energy utilization offered by the up-conversion process, and potential applications in more advanced packaging and agricultural fields.

Fe/LiNO3/TiN co–modified MgO for enhanced thermochemical energy storage performance in MgO/Mg(OH)2 cycles

MgO/Mg(OH)2 thermochemical energy storage can convert solar energy and industrial waste heat into forms that are easier to store and transport by cyclic hydration/dehydration reactions. To achieve excellent energy storage performance, cyclic stability and optical absorption capability of MgO/Mg(OH)2, Fe/LiNO3/TiN co–modified MgO were synthesized for energy storage cycles by wet-mixing method. The energy storage performance, cyclic stability and dehydration kinetics of Fe/LiNO3/TiN co–modified MgO were studied in dual fixed–bed system and simultaneous thermal analyzer. The experimental results show that the Fe and LiNO3 in the composite not only increase the hydration conversion of MgO by 6.3 times at 30 min, but also reduce the dehydration temperature and dehydration activation energy of Mg(OH)2 by 99.4 °C and 64 %, respectively. TiN overcomes aggregation of MgO and sustains the excellent porous structure, which results in only a 9 % decrease in energy storage performance of Fe/LiNO3/TiN co–modified MgO after 15 energy storage cycles. Subsequently, TiN significantly strengthens the optical absorption performance of Mg(OH)2 and photothermal temperature under xenon-lamp simulated sunlight radiation. Furthermore, density functional theory calculation reveals that Fe and Li enhance the adsorption of H2O on MgO model and reduce energy barrier for hydration reactions by 62.76 %, while TiN effectively inhibits MgO clusters migration within the material and enhances the optical absorption coefficient. Hence, Fe/LiNO3/TiN co–modified MgO shows significant research value in MgO/Mg(OH)2 energy storage process.

Coupling Cu Coordination Polymers with CdS Forming an S-Scheme Heterojunction for Rapid Charge Separation and High Photocatalytic Activity.

Energy and the environment are significant impacting factors for the future development of humankind. In order to improve the corrosion resistance of CdS and decrease the recombination of photogenerated carriers, a novel Cu-CPs@CdS heterojunction with high efficiency mesopores was constructed by a simple hydrothermal method. The effective interfacial contact formation between nano-CdS and Cu-CPs promotes the transfer of photogenerated carriers while exhibiting a high spatial separation rate of charges. The photocatalytic performance of the heterojunction was evaluated by the photocatalytic degradation of organic pollutants and photocatalytic hydrogen generation. The photocatalytic degradation of ciprofloxacin (CIP) could reach 90.34%, and the hydrogen generation was high as 9227.82 μmol·g-1 under simulated sunlight irradiation. The boosted photocatalytic activity of Cu-CPs@CdS results from (i) the formation of coordination bonds, which not only enhanced the stability of heterojunctions but also provided a path for photogenerated carrier migration, (ii) integrating Cu-CPs, which provided more active sites, and (iii) the matched energy band structure between CdS and Cu-CPs that promoted speedy S-scheme interfacial charge-transfer pathways, culminating in efficient photogenerated charge separation and transfer. This research offered a fresh tactic to restrict photocorrosion and enhance the production of photocatalytic H2 over CdS-based catalysts.

Insights into the photoreactivity mechanisms of micro-sized rubber particles with different structure: The crucial role of reactive oxygen species and released dissolved organic matter

Micro-sized rubber particles (MRPs), as a significant component of tire wear particles (TWPs), increasingly garnered attention due to the potential ecological risks. However, the impact of photoaging of MRPs and the characteristics of the dissolved organic matter (DOM) derived from MRPs on the photoreactivity of co-existing pollutants is remain unclear. To bridge this knowledge gap, this study selected MRPs with different structure including butadiene rubber (BR), styrene butadiene rubber (SBR) and nitrile butadiene rubber (NBR) and took tetracycline (TC) as the target pollutant to firstly study potential effects of structural characteristics and active components of MRPs on TC photodegradation process under simulated sunlight irradiation. The results indicated that BR, NBR and SBR enhanced TC photodegradation to varying extents, with SBR having the most pronounced effect. This effect was attributed mainly to the high electron transport capacity and the generation of more triple excited DOM (3DOM*) of SBR, thereby producing more active species (•OH and 1O2) and significantly promoting TC photodegradation. Additionally, the unsaturated bonds and aromatic groups in MRPs-DOM was identified as another crucial factor influencing their photoreactivity. This study will provide a new perspective for understanding the potential ecological effects between MRPs and co-existing pollutants in the natural environment.

Synthesis of strongly interactive FeWO4/BiOCl heterostructures for efficient photoreduction of CO2 and piezo-photodegradation of bisphenol A

Development of multi-functional photocatalysts for CO2 reduction and pollutant elimination is practically significant for solving the environmental problems and energy shortages. In this study, we have immobilized FeWO4 (FWO) nanoparticles on the surface of (001)-facet-exposed BiOCl (BOC) nanosheets through their strong electrostatic interaction to form FWO/BOC heterojunctions. Experimental and theoretical studies corroborate that the FWO/BOC heterojunctions exhibit high-efficiency Z-scheme transfer and separation of photocarriers, and possess excellent photocatalysis for CO2 reduction and bisphenol A (BPA) degradation. Under simulated-sunlight irradiation, the 9 %FWO/BOC heterojunction exhibits a photoreduction performance with CH4/CO yield rates of 4.25/9.41 μmol g−1 h−1 (5 h reaction), which are 3.86/5.26 times higher than those for bare BOC; whereas its photodegradation performance (η(60 min) = 66.8 %, kapp = 0.01755 min−1) is enhanced by 4.3 and 2.7 times compared with that of bare FWO and BOC, respectively. Furthermore, when ultrasonic vibration is simultaneously employed during the simulated-sunlight illumination, the ultrasonic-induced piezoelectric polarization field in BOC nanosheets accelerates the bulk photocarrier separation, resulting in a further improvement in the BPA degradation, and the calculated SF = 1.79 quantifies the degree of enhancement achieved by piezo-photocatalysis collaboration. The introduction of a moderate amount of H2O2 or peroxymonosulfate (PMS) in the reaction solution plays a significant role in promoting the BPA degradation due to the generation of additional •OH and •SO4− reactive species. The mechanisms for photocatalytic CO2 reduction and piezo-photodegradation of BPA catalysis were deeply studied by combining experiments and theory.

Unveiling Mechanistic Insight into Accelerating Oxygen Molecule Activation by Oxygen Defects in Co3O4-x/g-C3N4 p-n Heterojunction for Efficient Photo-Assisted Uranium Extraction from Seawater.

Photo-assisted uranium extraction from seawater (UES) is regarded as an efficient technique for uranium resource recovery, yet it currently faces many challenges, such as issues like biofouling resistance, low charge separation efficiency, slow carrier transfer, and a lack of active sites. Based on addressing the above challenges, a novel oxygen-deficient Co3O4-x/g-C3N4 p-n heterojunction is developed for efficient photo-assisted uranium extraction from seawater. Relying on the defect-coupling heterojunction synergistic effect, the redistribution of molecular charge density formed the built-in electric field as revealed by DFT calculations, significantly enhancing the separation efficiency of carriers and accelerating their migration rate. Notably, oxygen vacancies served as capture sites for oxygen, effectively promoting the generation of reactive oxygen species (ROS), thereby significantly improving the photo-assisted uranium extraction performance and antibacterial activity. Thus, under simulated sunlight irradiation with no sacrificial reagent added, Co3O4-x/g-C3N4 extracted a high uranium extraction amount of 1.08mgg-1 from 25 L of natural seawater after 7 days, which is superior to most reported carbon nitride-based photocatalysts. This study elaborates on the important role of surface defects and inerface engineering strategies in enhancing photocatalytic performance, providing a new approach to the development and design of uranium extraction material from seawater.

Photochemical transformation altered coagulation behavior and treatability of dissolved organic matters in water

The photo-transformation of dissolved organic matter (DOM), which is ubiquitous in aquatic environments, significantly alters its molecular composition and interactions in surface water environment, affecting its fate in water treatment processes. However, the effect of photo-transformation on the coagulation behavior of DOM remains poorly understood. Herein, the photo-transformation pathways of DOM during simulated sunlight irradiation and its effect on coagulation behavior of DOM were investigated. Reactomics analysis demonstrated the polyphenols in DOM underwent dealkylation reactions, reactions of carboxylic acid, and oxygen addition reactions upon sunlight irradiation, generating molecules with low aromaticity and molecular weight, and low-oxygen-content fragments. Such alterations resulted in a reduction in the relative abundance of the dominant component being C&O-rich lignin-like compounds enriched in –CH2CO2, –2COOH, and –2OH groups, leading to the decrease of DOM removal efficiency. These alterations caused a variation in coagulation mechanisms for DOM removal, shifting from charge neutralization to adsorption bridging after 36 h of simulated sunlight irradiation. This study offers novel insights into the effects of photo-oxidation on the coagulation behaviour of DOM, contributing to the optimization of drinking water treatment and the safe supply of drinking water.

Dissecting the Photochemical Reactivity of Metal Ions during Atmospheric Nitrate Transformations on Photoactive Mineral Dust.

Dissecting the photochemical reactivity of metal ions is a significant contribution to understanding secondary pollutant formation, as they have a role to be reckoned with atmospheric chemistry. However, their photochemical reactivity has received limited attention within the active nitrogen cycle, particularly at the gas-solid interface. In this study, we delve into the contribution of magnesium ion (Mg2+) and ferric ion (Fe3+) to nitrate decomposition on the surface of photoactive mineral dust. Under simulated sunlight irradiation, the observed NOX production rate differs by an order of magnitude in the presence of Mg2+ (6.02 × 10-10 mol s-1) and Fe3+ (2.07 × 10-11 mol s-1). The markedly decreased fluorescence lifetime induced by Mg2+ and the change in the valence of Fe3+ revealed that Mg2+ and Fe3+ significantly affect the concentration of nitrate decomposition products by distinct photochemical reactivity with photogenerated electrons. Mg2+ promotes NOX production by accelerating charge transfer, while Fe3+ hinders nitrate decomposition by engaging in a redox cyclic reaction with Fe2+ to consume photogenerated carriers continuously. Furthermore, when Fe3+ coexists with other metal ions (e.g., Mg2+, Ca2+, Na+, and K+) and surpasses a proportion of approximately 12%, the photochemical reactivity of Fe3+ tends to be dominant in depleting photogenerated electrons and suppressing nitrate decomposition. Conversely, below this threshold, the released NOX concentration increases sharply as the proportion of Fe3+ decreases. This research offers valuable insights into the role of metal ions in nitrate transformation and the generation of reactive nitrogen species, contributing to a deep understanding of atmospheric photochemical reactions.

Photoelectrochemistry hydrogen production based on aggregation induced emission active 1,1,2,2-tetrakis(4-(9H-carbazol-9-yl)phenyl)ethene polymer, Au nanoparticles and ascorbic acid

Aggregation induced emission (AIE) active molecules have emerged as a kind of unique and important functional materials of wide scientific and technical interests, but the photoelectrochemistry (PEC) of AIE-active molecules is still little understood to date. Herein, we investigate the first-time use of AIE-active molecules for PEC hydrogen production. Au nanoparticles (AuNPs) were electrodeposited on an indium tin oxide (ITO) electrode and AIE-active 1,1,2,2-tetrakis(4-(9H-carbazol-9-yl)phenyl)ethene (TCPE) was then electropolymerized to obtain a PTCPE/AuNPs/ITO photoanode (PTCPE = poly(TCPE)). Under 100 mW cm−2 AM 1.5G simulated sunlight irradiation at a bias of 0 V vs RHE in 0.5 M aqueous Na2SO4 containing 0.1 M ascorbic acid (AA), the photocurrent density of this photoanode was 1.32 mA cm−2 (0.16 mA cm−2 if simply without AA), which is notably higher than those of PTCPE/ITO (0.43 mA cm−2) and AuNPs/ITO (0.62 μA cm−2) control photoanodes. The excellent PEC performance is explained by the broadened light absorption range of PTCPE versus the monomer, the quenching of PTCPE fluorescence via the efficient electron transfer from the lowest unoccupied molecular orbital of PTCPE to AuNPs, and the consumption of the photogenerated holes on the highest occupied molecular orbital of PTCPE by AA, because all these factors can improve the separation and transfer of photogenerated charges. This work may have provided a reference for exploring new applications of AIE-active molecules and developing new PEC and photocatalysis materials.

Full solar-spectrum available Z-scheme MOF-on-MOF heterostructure for highly efficient photocatalytic VSCs removal

The construction of efficient photocatalysts with strong response to sunlight is crucial for clean and sustainable pollutant degradation and environmental remediation. Herein, a novel MOF-on-MOF structural photocatalyst named HKU@MIL with Z-scheme heterojunction was successfully designed. The light response of the composites effectively extends to the whole solar spectrum through a simple activation process, addressing the issue of the low utilization of sunlight by photocatalysts. The photocatalytic degradation rate of methyl mercaptan by activated HKU@MIL is 2.2, 3.2, and 1.8 times higher than that of NH2-MIL-125, HKUST-1, and HKU/MIL-5 (physical mixtures), respectively. Under simulated sunlight irradiation, the rate constant increases to 0.507 min−1, which is 1.4 times higher than that under visible light. Additionally, the composites exhibit good photocatalytic performance when irradiated with near-infrared light alone. The heterojunction type of the photocatalyst was investigated according to in-depth analysis of X-ray photoelectron spectroscopy. Additionally, the interfacial charge transmission mode of the composites and the probable pathways for methyl mercaptan degradation were explored through band structure analysis, radical quenching tests and electron spin resonance analysis. The improved photocatalytic performance of activated HKU@MIL can be attributed to the full solar spectral response and the successful creation of the Z-scheme electron migration channel, which serves to reinforces the electron pump effect. It achieves this by improving the transmission of photogenerated carriers and ensuring the strongest redox potential. This work presents a new perspective on enhancing the utilization of sunlight by photocatalysts and improving the photocatalytic performance of heterojunction photocatalysts used in environmental remediation.

Improving the Water Resistance of Bi‐Based Perovskite‐Inspired Materials for Vapor‐Phase Photocatalytic Overall Water Splitting

Lead halide perovskites are well known for their exceptional photophysical and electronic properties, which have placed them at the forefront of challenging optoelectronic applications and solar‐to‐fuel conversion. However, their air/water instability, combined with their toxicity, is still a critical problem that has slowed down their commercialization. In this sense, bismuth‐based halide derivatives attract much interest as a potentially safer, air‐stable alternative. Herein, a novel Bi‐based perovskite‐inspired material, IEF‐19 (IEF stands for IMDEA Energy Framework), which contains a bulky aromatic cation (1,5‐diammonium naphthalene), is prepared. Additionally, an N‐alkylation strategy is successfully employed to achieve four water‐stable perovskite‐inspired materials, which contains diammonium naphthalene cations that are tetra‐alkylated by methyl, ethyl, propyl, and butyl groups. Moreover, computational studies are performed to gain a deeper understanding of the intrinsic structural stability and affinity of water molecules for Bi‐based perovskite‐inspired materials. Importantly, the air‐ and water‐stable IEF‐19‐Et (i.e., stable at least 12 months under ambient conditions and 3 weeks in contact with water) is found to be an active photocatalyst for vapor‐phase overall water splitting in the absence of any sacrificial agent under both ultraviolet–visible or simulated sunlight irradiation. This material exhibits an estimated apparent quantum yield of 0.08% at 400 nm, partially explained by its adequate energy band level diagram.

Photothermal-enabled metal-free polyfuran photocatalysts for efficient solar-to-hydrogen peroxide energy conversion from seawater

Solar-driven H2O2 photosynthesis from inexhaustible seawater is promising for alleviating increasingly-serious energy/environmental crises. Herein, a new metal-free photothermal-assisted photocatalyst containing strong π-stacked polyfuran D-A couples is synthesized by employing 5-hydroxymethylfurfural as precursor, which enables the highly-efficient H2O2 photosynthesis from seawater without any sacrificial agent. Its unique aromatic and quinoid furan alternating structure promotes the photogenerated charge transfer and the activation of oxygen molecules, thus remarkedly boosting H2O2 production rate. Furthermore, its localized photothermal and “electron bridge” effects can enhance the kinetic process of this reaction and accelerate the charge transfer, respectively, resulting in a high H2O2 yield of 1883.81 μmol g−1 h−1 with a high solar-to-chemical conversion efficiency of 0.48 % in seawater under simulated-sunlight irradiation. Impressively, it can achieve a high H2O2 concentration of 1867.81 μmol L−1 in natural seawater in one day under natural-sunlight irradiation, representing the first successful application of metal-free polyfuran photocatalysts for the photothermal-assisted H2O2 photosynthesis from natural seawater.

Research on the fabrication of nanorod-structured phorphyrin/g-C3N4 as photocatalyst materials for the removal of Cr6+ ions in an aqueous solution

Due to their potential to expand the photon energy harvesting zones and improve charge separation, two semiconductors together have been shown to be a promising technique to increase the photocatalytic activity of photocatalysts. Through the use of monomeric porphyrin molecules and g-C3N4 nanomaterials, self-assembly of the hybird g-C3N4@porrphyrin nanorod materials under CTAB surfactant-assited conditions was demonstrated in this study. SEM, EDS, FTIR, and UV-vis were used to characterize the generated hybrid material. Under simulated sunlight irradiation, the hybrid mateial’s photocatalytic behaviour was examined for the photoreduction of Cr6+ ions. After 100 minutes of reaction time under the simulated solar spectrum, the results showed that the hybrid material demonstrated high photocatalytic performance against, with clearance percentage of almost 100%. The prepared photocatalyst was also highly stable with the reduction of Cr6+ removal efficiency of less than 10% after 4 cycles of photocatalytic testing.

Fabrication of ZnO-carbon dots composite via microcrystalline cellulose for enhanced photocatalytic hydrogen production under simulated sunlight irradiation

The composite ZnO@CDs was prepared via the hydrothermal method. Microcrystalline cellulose (MCC) was used as the source of carbon dots (CDs). X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, and transmission electron microscopy analyses were used to characterize the structure and morphology of ZnO@CDs. The prepared ZnO showed a flake morphology with the exposed plane of (001). The X-ray photoelectron spectroscopy and photoluminescence spectroscopy (PL) characterization showed that CDs can be produced by decomposition of MCC and then attached on the surface of ZnO. The photocatalytic properties of ZnO@CDs were investigated under simulated sunlight irradiation. The hydrogen production reached 1240 µmol·g-1 in 30 min, which was much higher than the bare ZnO. The mechanism for the enhanced catalytic property of ZnO@CDs was studied. A high hydrogen production rate (2480 µmol·g-1·h-1) in the short term would enable ZnO@CDs to work as an emergency power supply by hydrogen production and use for restoring electricity and wireless communication in complicated situations.

Photocatalytic Reduction of Perrhenate and Pertechnetate in a Strongly Acidic Aqueous Solution.

Pertechnetate (99TcO4-), a physiologically toxic radioactive anion, is of great concern due to its high mobility in environmental contamination remediation. Although the soluble oxyanion can be photoreduced to sparingly soluble TcO2·nH2O, its effective removal from a strongly acidic aqueous solution remains a challenge. Here, we found that low-crystalline nitrogen-doped titanium oxide (N-TiO2, 0.6 g L-1) could effectively uptake perrhenate (ReO4-, 10 mg L-1, a nonradioactive surrogate for TcO4-) with 50.8% during 360 min under simulated sunlight irradiation at pH 1.0, but P25 and anatase could not. The nitrogen active center formed by trace nitrogen doping in N-TiO2 can promote the separation and transfer of photogenerated carriers. The positive valence band value of N-TiO2 is slightly higher than those of P25 and anatase, which means that the photogenerated holes have a stronger oxidizability. These holes are involved in the formation of strong reducing •CO2- radicals from formic acid oxidation. The active radicals convert ReO4- to Re(VI), which is subsequently disproportionated to Re(IV) and Re(VII). Effective photocatalytic reduction/removal of Re(VII)/Tc(VII) is performed on the material, which may be considered a potential and convenient strategy for technetium decontamination and extraction in a strongly acidic aqueous solution.

Retraction: "Water splitting system with a 13.1% solar to hydrogen conversion efficiency using 3-junction III-V solar cells with pulse plated Pt black catalyst"

Retraction The authors hereby retract the above article. This paper reports on a highly efficient system for water splitting using a three-junction solar cell with a platinum black catalyst under simulated sunlight. After this manuscript was accepted, it was found that there was an error in the conditions for electroplating the platinum black catalyst on the solar cell. Specifically, there was an error in the settings for the pulse power supply used when plating platinum black. Although the pulse current, pulse width, and cycle were set correctly, the base current value was the same as the pulse current, which was found in a separate experiment using the same equipment. The authors checked the current output under the conditions described in this manuscript using an oscilloscope, and it was confirmed that it was a direct current, not a pulsed current. The measurement results for hydrogen production under simulated sunlight irradiation presented in the paper were correct, and the conclusions regarding hydrogen production were also correct. However, there was an error in the plating conditions for platinum black described in the paper, and the title and content of the discussion also needed to be revised. Based on the above, the authors reached the consensus that the above paper should be retracted and that the authors will submit it again as a new paper with no mistakes in the Japanese Journal of Applied Physics.

Black Ultrathin Single-Crystalline Flakes of CuVP2S6 and CuCrP2S6 for Near-Infrared-Driven Photocatalytic Hydrogen Evolution.

The development of new near-infrared-responsive photocatalysts is a fascinating and challenging approach to acquire high photocatalytic hydrogen evolution (PHE) performance. Herein, near-infrared-responsive black CuVP2S6 and CuCrP2S6 flakes, as well as CuInP2S6 flakes, are designed and constructed for PHE. Atom-resolved scanning transmission electron microscopy images and X-ray absorption fine structure evidence the formation of ultrathin single-crystalline sheet-like structure of CuVP2S6 and CuCrP2S6. The synthetic CuVP2S6 and CuCrP2S6, with a narrow bandgap of ≈1.0eV, shows the high light-absorption edge exceeding 1100nm. Moreover, through the femtosecond-resolved transient absorption spectroscopy, CuCrP2S6 displays the efficient charge transfer and long charge lifetime (18318.1ps), which is nearly 3 and 29 times longer than that of CuVP2S6 and CuInP2S6, respectively. In addition, CuCrP2S6, with the appropriate d-band and p-band, is thermodynamically favorable for the H+ adsorption and H2 desorption by contrast with CuVP2S6 and CuInP2S6. As a result, CuCrP2S6 exhibits high PHE rates of 9.12 and 0.66mmol h-1 g-1 under simulated sunlight and near-infrared light irradiation, respectively, far exceeding other layered metal phospho-sulfides. This work offers a distinctive perspective for the development of new near-infrared-responsive photocatalysts.

Aqueous degradation of tioxazafen: Kinetics, products, pathways, and toxicity

Tioxazafen (TXF) is the first 1,2,4-oxadiazole nematicide. In the present study, the aqueous degradation of TXF was investigated in terms of hydrolysis and photolysis. Under the irradiation of simulated sunlight, TXF degraded very fast in ultrapure water and buffers with half-lives (t1/2s) <8.3 min. A sole photoproduct (PP) PP228a was isolated, and identified by spectroscopic means (UV, IR, HRMS, and 1H NMR) to be the thiophen-3-yl isomer converted from its thiophen-2-yl parent. Comparing with TXF, PP228a had quite extended t1/2s ranging from 6.9 to 7.9 d. The photolysis kinetics of TXF and PP228a showed no pH-dependence, and varied for each individual compound as affected by nitrate, fulvic acid, and humic acid. Besides, both compounds were hydrolytically stable. 6 PPs of PP228a were identified, with two of them being its isomers. The mechanisms involved in the process included the biradical photosensitization, photoinduced electron transfer, and ring contraction-ring expansion reactions. The 48 h-EC50 to Daphnia magna was 0.808 mg/L for PP228a comparing to >1.12 mg/L for TXF, while the results of Vibrio fischeri assays indicated that one or more PPs of PP228a might have higher toxicity.