Min In Dark Research Articles

Round-the-clock efficient degradation and simultaneous hydrogen evolution over long afterglow light driven Z-scheme Cu|CuO/SrAl2O4:Eu2+,Dy3+ photocatalyst composite film

The dependence of photocatalytic technology on external irradiation light sources limits the round-the-clock utilization of photocatalysts. Meanwhile, CO2 and H2 generated on the photocatalysts are mixed together because traditional photocatalysts are mostly powdery, which requires further separation and purification of the generated gases. In this work, an immobilized Z-scheme Cu|CuO/SrAl2O4:Eu2+,Dy3+ composite film was successfully prepared for the first time as a photocatalyst, enabling round-the-clock degradation of ciprofloxacin and hydrogen evolution on both sides of copper foil. The efficiency of ciprofloxacin degradation and hydrogen evolution was systematically investigated to evaluate the performance of the prepared samples. The results showed that after 180 min of continuous simulated solar irradiation followed by 240 min in darkness, the degradation efficiency reached 84.78 % for ciprofloxacin and 672.29 μmol/g for hydrogen evolution. This work aims to contribute to round-the-clock photocatalytic degradation of organic pollutants and hydrogen evolution.

Efficient antibiotic degradation catalyzed by oxygen vacancy and Cu-Doped Cu-MOF under visible light

The widespread use of antibiotics in contemporary healthcare has led to their accumulation in natural water systems, contributing to a growing resistance among bacteria and posing a significant challenge to the sustainable development of human society. Photocatalysis has emerged as an effective technique to mitigate antibiotic pollution in water. This study focuses on developing and synthesizing a visible light responsive metal–organic framework (MOF), Cu-NTC, which employs copper as the metal node instead of the usual choice of molybdenum, and the rigid 1,4,5,8-naphthalene tetracarboxylic acid (H4NTC) as the organic ligand. A pivotal step in the synthesis involved the partial reduction of Cu2+, leading to the formation of Cu0/Cu+ doping. This doping, together with oxygen vacancies (OVs), introduces a localized state that functions as a doped energy level, thus prolonging carrier lifetime and enhancing the visible light photocatalytic activity of Cu-NTC. Remarkably, Cu-NTC achieved photocatalytic degradation efficiencies of 84.5 % for tetracycline (TC) and 96.1 % for norfloxacin (NFX) after 30 min in darkness followed by 120 min under visible light exposure. Moreover, Cu-NTC exhibited effective removal capabilities for other antibiotics within the quinolone and tetracycline groups, underscoring their potential for broader applications in water purification.

Endophytic Aspergillus hiratsukae mediated biosynthesis of silver nanoparticles and their antimicrobial and photocatalytic activities.

In the current study, endophytic Aspergillus hiratsukae was used for the biosynthesis of silver nanoparticles (Ag-NPs) for the first time. The characterizations were performed using X ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), and UV-Vis spectroscopy. The obtained results demonstrated the successful formation of crystalline, spherical Ag-NPs with particle diameters ranging from 16 to 31 nm. The FT-IR studied and displayed the various functional groups involved, which played a role in capping and reducing agents for Ag-NPs production. The SEM-EDX revealed that the main constituent of the AS-formed sample was primarily Ag, with a weight percentage of 64.2%. The mycosynthesized Ag-NPs were assessed for antimicrobial as well as photocatalytic activities. The antimicrobial results indicated that the synthesized Ag-NPs possess notable antibacterial efficacy against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli, with minimum inhibitory concentrations (MICs) of Ag-NPs ranging from 62.5 to 250 μg/mL. Moreover, the biosynthesized Ag-NPs demonstrated weak antifungal activity against Aspergillus brasiliensis and Candida albicans, with MICs of 500 and 1,000 μg/mL, respectively. In addition, the mycosynthesized Ag-NPs exhibited photocatalytic activity toward acid black 2 (nigrosine) dye under both light and dark stimulation. Notably, After 300 min exposure to light, the nigrosine dye was degraded by 93%. In contrast, 51% degradation was observed after 300 min in darkness. In conclusion, Ag-NPs were successfully biosynthesized using endophytic A. hiratsukae and also exhibited antimicrobial and photocatalytic activities that can be used in environmental applications.

Red pigment from isolated Serratia marcescens SEM: Structure, antimicrobial and antioxidant activity

Pigments from microbial sources are likely to be suitable alternatives to synthetic pigments. Not only do natural pigments have the potential to increase product marketability, but they also exhibit valuable biological activities as antioxidants and antimicrobial agents. Recently, microbial prodigiosin (PG) has received a lot of attention due to its many beneficial applications. PG is a natural red dye. It is an alkaloid secondary metabolite with a unique tertiary structure produced by Serratia marcescens. The purpose of our study was to isolate indigenous strains of S. marcescens and identify it, extraction the red pigment from culturable bacteria to confirm its structure, evaluate its antimicrobial activity against a series of pathogenic microbes (Staphylococcus aureus NRRL B-313 and Bacillus subtilus NRC, Escherichia coli NRC B-3703, Pseudomonas aeruginosa NRC B-32, Candida albicans ATCC1023 and Aspergillus niger NRC) by well diffusion assay and antioxidant activities by DPPH assay. The isolate was identified by morphological characteristics and 16S rRNA sequencing as S. marcescens SEM, with accession number OM757735.1. PG from S. marcescens was first confirmed its purity by UV absorption spectrum, FTIR and GC-MS spectrophotometer. PG possess effective antimicrobial activity against tested pathogens, with MIC 1.0 ± 0.15, 5.0 ± 0.25, 16.5 ± 0.87, 16.5 ± 0.92 and 3.3 ± 0.17 μg/mL against B. cereus, St. aureus, E. coli, P. aurgenosa, and C. albicans, respectively. Also, PG possess highly antioxidant activity 97.2% at the concentration of 400 μg/ml after 120 min in dark, this activity increased gradually with increasing concentrations and time of incubation in dark,with IC50 (250 μg/ml at 30 min; 225 μg/ml at 60 min; 200 μg/ml at 90 min; 125 μg/ml at 120 min).

Survival and thermal resistance of Salmonella in chocolate products with different water activities

Contamination of Salmonella in chocolate products has caused worldwide outbreaks and recalls. There is a lack of information on the impact of water activity (aw) on the stability of Salmonella in chocolate products during storage and thermal treatments. In this research, the survival and thermal resistance of a Salmonella cocktail (S. Enteritidis PT30, S. Tennessee K4643, S. Typhimurium S544) was examined in different chocolate products (dark chocolate, white chocolate, milk chocolate) at two aw levels (0.25, 0.50) over 12 months at 22 °C. A reduction of 4.19 log10 CFU/gof Salmonella was obtained in dark chocolate after 12 months (aw = 0.50, at 22 °C); less reductions were observed in white and milk chocolates. In all three products, more reductions were observed ataw = 0.50 than at aw = 0.25 over the 12-months storage. When treated at 80 °C, the D-values (time required to cause 1 log reduction) of the Salmonella cocktail in the chocolate samples with initial aw of 0.25 were 35.7, 25.2 and 11.6 min in dark, white and milk chocolate, respectively, before the storage. The D80°C -values of Salmonella cocktail in the samples with initial aw of 0.50 were 6.45, 7.46, and 3.98 min in dark, white and milk chocolate, respectively. After 12 months of storage at 22 °C, the D80°C-value of Salmonella cocktail decreased to 9.43 min (p < 0.05) in milk chocolate but remained 22.7 min in white chocolate with an aw of 0.25 at 22 °C. The data suggests that Salmonella can survive in chocolate products for up to 12 months, and its thermal resistance remained relatively stable. Thus, Salmonella is resistant to desiccation in chocolates, particularly in milk and white chocolates, and its thermal resistance remains during one-year storage, which could pose a potential threat for future outbreaks.

Freezing degradation of the anticonvulsant oxcarbazepine by bromate in water ice under sunlight irradiation

Ice plays a crucial role in contaminant transformation in seasonally ice-covered waters. In this study, the characteristics and mechanisms of an emerging contaminant oxcarbazepine (OXC) degradation by a disinfection by-product bromate (BrO3–) in ice were explored via combined experiments and theoretical calculations. Results showed that 74.0 % and 86.4 % of OXC was degraded by BrO3– in ice after 140 min in dark and 120 min under solar irradiation, respectively, while the reaction was negligible in water. The oxidation-reduction potential of BrO3– solution at 1000 μmol L−1 was 56.9 % higher than that at 50 μmol L−1. The oxidation-reduction potential of BrO3– solution at pH 2 was 14.8 %–109.5 % higher than those at other pH values. Enhanced OXC degradation by BrO3– in ice could be attributed to increased BrO3– oxidation capacity resulting from locally elevated BrO3– and H+ concentrations. Hypobromous acid (HOBr), •OH, and Br• generated by direct photolysis under solar irradiation further promoted the OXC degradation in ice. Br• formed by the direct photolysis of accumulated HOBr under solar irradiation caused the generation of bromine-containing degradation products. Bromine-containing degradation products possessed higher potential toxicities, which could contribute to increase the secondary pollution of water environment.

Construction of UiO-66-NH2/BiOBr heterojunctions on carbon fiber cloth as macroscale photocatalyst for purifying antibiotics

Metal-Organic Frameworks (MOFs) as a novel semiconductor-like material with high adsorption were used to combine with other efficient semiconductors to enhance the adsorption capacity and photocatalytic activity for removing antibiotics from aqueous solutions. In addition, most of the efficient photocatalysts are in powder-shaped, making recycling problematic. To solve the above problems, with macroscale carbon fiber cloth (CFC) as the substrate, Zr-based MOFs (UiO-66-NH2) as a model material with ultra-high specific area and BiOBr as an efficient semiconductor with irregular sheet structure were synthesized sequentially by a solvothermal method and dip-coating process. The prepared CFC/UiO-66-NH2/BiOBr exhibits strong adsorption of 65.4% levofloxacin (LVFX) or 16.8% ciprofloxacin (CIP) within 60 min in dark, and excellent degradation of 92.2% LVFX or 86.4% CIP under visible-light irradiation over a period of 120min. Additionally, after 4 cycles of visible-light irradiation, the macroscale CFC/UiO-66-NH2/BiOBr exhibits stable removal efficiency of antibiotics. Using low-cost CFC as substrate, CFC/UiO-66-NH2/BiOBr shows high efficiency and recyclability in removing antibiotics from polluted wastewater, offering guidance for developing highly effective photocatalysts on a large scale through methods like calcination and sol-gel synthesis. Therefore, the macroscale CFC/UiO-66-NH2/BiOBr has great potential for purifying antibiotics under visible-light illumination, presenting a practical solution for sustainable development.

Watching the human retina breath in real time and the slowing of mitochondrial respiration with age

The retina has the greatest metabolic demand in the body particularly in dark adaptation when its sensitivity is enhanced. This requires elevated level of perfusion to sustain mitochondrial activity. However, mitochondrial performance declines with age leading to reduced adaptive ability. We assessed human retina metabolism in vivo using broad band near-infrared spectroscopy (bNIRS), which records colour changes in mitochondria and blood as retinal metabolism shifts in response to changes in environmental luminance. We demonstrate a significant sustained rise in mitochondrial oxidative metabolism in the first 3 min of darkness in subjects under 50 years old. This was not seen in those over 50 years. Choroidal oxygenation declines in < 50 s as mitochondrial metabolism increases, but gradually rises in the > 50 s. Significant group differences in blood oxygenation are apparent in the first 6 min, consistent with mitochondrial demand leading hemodynamic changes. A greater coupling between mitochondrial oxidative metabolism with hemodynamics is revealed in subjects older than 50, possibly due to reduced capacity in the older retina. Rapid in vivo assessment of retinal metabolism with bNIRS provides a route to understanding fundamental physiology and early identification of retinal disease before pathology is established.

The mesoglea buffers the physico-chemical microenvironment of photosymbionts in the upside-down jellyfish Cassiopea sp.

IntroductionThe jellyfish Cassiopea has a conspicuous lifestyle, positioning itself upside-down on sediments in shallow waters thereby exposing its photosynthetic endosymbionts (Symbiodiniaceae) to light. Several studies have shown how the photosymbionts benefit the jellyfish host in terms of nutrition and O2 availability, but little is known about the internal physico-chemical microenvironment of Cassiopea during light–dark periods.MethodsHere, we used fiber-optic sensors to investigate how light is modulated at the water-tissue interface of Cassiopea sp. and how light is scattered inside host tissue. We additionally used electrochemical and fiber-optic microsensors to investigate the dynamics of O2 and pH in response to changes in the light availability in intact living specimens of Cassiopea sp.Results and discussionMapping of photon scalar irradiance revealed a distinct spatial heterogeneity over different anatomical structures of the host, where oral arms and the manubrium had overall higher light availability, while shaded parts underneath the oral arms and the bell had less light available. White host pigmentation, especially in the bell tissue, showed higher light availability relative to similar bell tissue without white pigmentation. Microprofiles of scalar irradiance into white pigmented bell tissue showed intense light scattering and enhanced light penetration, while light was rapidly attenuated over the upper 0.5 mm in tissue with symbionts only. Depth profiles of O2 concentration into bell tissue of live jellyfish showed increasing concentration with depth into the mesoglea, with no apparent saturation point during light periods. O2 was slowly depleted in the mesoglea in darkness, and O2 concentration remained higher than ambient water in large (&amp;gt; 6 cm diameter) individuals, even after 50 min in darkness. Light–dark shifts in large medusae showed that the mesoglea slowly turns from a net sink during photoperiods into a net source of O2 during darkness. In contrast, small medusae showed a more dramatic change in O2 concentration, with rapid O2 buildup/consumption in response to light–dark shifts; in a manner similar to corals. These effects on O2 production/consumption were also reflected in moderate pH fluctuations within the mesoglea. The mesoglea thus buffers O2 and pH dynamics during dark-periods.

Manipulating the Migration of Iodine Ions via Reverse-Biasing for Boosting Photovoltaic Performance of Perovskite Solar Cells.

Perovskite solar cells (PSCs) are being developed rapidly and exhibit greatly potential commercialization. Herein, it is found that the device performance can be improved by manipulating the migration of iodine ions via reverse-biasing, for example, at -0.4V for 3min in dark. Characterizations suggestthat reverse bias can increase the charge recombination resistance, improve carrier transport, and enhance built-in electric field. Iodine ions including iodine interstitials in perovskites are confirmed to migrate and accumulate at the SnO2 /perovskite interface under reverse-basing, which fill iodine vacancies at theinterface and interact with SnO2 . First-principles calculations suggest that the SnO2 /perovskite interface with less iodine vacancies has a stronger interaction and higher charge transfer, leading to larger built-in electric field and improved charge transport. Iodine ions that may pass through the SnO2 /perovskite interface are also confirmed to be able to interact with Sn4+ and passivate oxygen vacancies on the surface of SnO2 . Consequently, an efficiency of 23.48% with the open-circuit voltage (Voc ) of 1.16V is achieved for PSCs with reverse-biasing, as compared with the initial efficiency of 22.13% with aVoc of 1.10V. These results are of great significance toreveal the physics mechanism of PSCs under electric field.

Enhanced performance and recyclability for peroxymonosulfate activation via g-C3N4 supported CoFe layer double oxide

CoFe layered double oxide (CoFe LDO) anchored on g-C3N4 was prepared by mixing appropriate amounts of CoFe layer double hydroxide and melamine at moderate synthesis temperatures. The resulting CoFe LDO/g-C3N4 composite has superior properties in peroxymonosulfate (PMS) activation, resulting in remarkable activity in catalyzing paracetamol degradation. It has been able to degrade 10 mg/L paracetamol in less than 10 min in darkness by using 0.2 g/L catalyst and 0.5 mM PMS dosages. The effects of PMS and catalyst dosage, initial pH and coexisting anions were also investigated. Negligible cation leaching, enhanced reusability and enhanced stability make CoFe LDO/g-C3N4 an attractive compound for environmental pollution abatement. The influence of g-C3N4 on lowering Co and Fe valence states in CoFe LDO compounds by covalent stimulates the oxidant radical (SO4− and OH) production and concomitantly paracetamol degradation. Electro magnetic resonance experiments and a so-called chemical probe were used to identify SO4− as the dominant radical in the degradation processes. Interestingly, X-ray absorption spectroscopy and electrochemical measurements revealed the existence of a second contributing mechanism, based on a pure electron transfer process from the pollutant to PMS mediated by the catalyzer. These findings, pioneer a new method for the mechanism of coupling radical and electron transfer processes that act synergistically to promote paracetamol degradation in scarcely 10 min in darkness.

Room-Temperature Persistent Luminescence in Metal Halide Perovskite Nanocrystals for Solar-Driven CO 2 Bioreduction

Room-Temperature Persistent Luminescence in Metal Halide Perovskite Nanocrystals for Solar-Driven CO ₂ Bioreduction

Paracetamol degradation by photo-assisted activation of peroxymonosulfate over ZnxNi1−xFe2O4@BiOBr heterojunctions

Developing efficient and recyclable heterogeneous catalysts in advanced oxidation processes towards aqueous organic pollutants degradation on real samples remains challenging. Herein, semiconductor heterojunction photocatalysts with variable composition (ZnxNi1−xFe2O4@BiOBr; x = 0, 0.2, 0.5, 0.8 and 1) were synthesized through a two steps hydrothermal process. The influence of cation composition, microstructure heterojunction, catalyst and peroxymonosulfate (PMS) dosage and pH variation were investigated for the degradation of paracetamol (PAM) as target pollutant. Real degradation datasets from commercial tablet solutions were compared with pure paracetamol (p-PAM). Doping Ni into ZnFe2O4 significantly affect the catalytic performance as well as enable magnetic removal of catalyst. The ratio between ZnxNi1−xFe2O4 and BiOBr was also optimized to realize best catalytic degradation. Complete removal of PAM was achieved after 100 min at optima conditions (0.5 g/L Zn0.8Ni0.2Fe2O4@BiOBr, 2 mM PMS, 10 mg/L PAM, UV-A, pH 7) while 64% removal account in 100 min in darkness. A chemical method probe, through free radical scavengers, revealed that SO4•- is the main specie involved in the degradation reaction. A novel degradation mechanism was proposed by the identification of eight different intermediates. Reusability of the heterojunction photocatalysts was studied after five consecutive treatments. Zn0.8Ni0.2Fe2O4@BiOBr efficiently activate PMS under UV-A irradiation vanishing PAM, one contaminants of most emerging concern found in water. This study will shed light into the understanding of photo-assisted PMS activation for aqueous pollution abatement.

Solar energy conversion to electricity by Tris (2,2′-bipyirdyl) ruthenium (II) chloride hexahydrate-diethyl ammonium tetrachloroferrate-oxalic acid photogalvanic cell: Statistical analysis

Surfactants are commonly used in photogalvanic cells (PGC) while few studies have reported on the application of ionic liquids (IL), although it is considered as green solvents. In this work, diethyl ammonium tetrachloroferrate (DATF) was synthesized by two-step method. The chemical structure of the DATF was studied using FTIR and 1H NMR spectra. PGC can be pronounced as an electrochemical cell in which the change in both voltage and current produced from photochemical changes in the solutions during the oxidation-reduction reaction. A new system of synthetic solution contains Tris (2,2′-bipyridyl) Ruthenium (II) chloride hexahydrate (TBRC) photosensitizer dye, Oxalic acid (OX) reductant, and DATF was used under artificial illumination. The used system shows electrical cell performance of maximum power (PPP) 96.2 μW, short-circuit current (iSC) 370 μA, open circuit potential (VOC) 650 mV, conversion efficiency (η) 1.9 %, and fill factor (FF) 0.4. The storage capacity (t0.5) of the cell has recorded 105 min in dark. Different parameters affect the cell performance as were studied. The cell parameters and a preliminary mechanism of the production of electrical energy in PGC were also proposed. Response surface methodology (RSM) approach was used to optimize the process parameters and identifying the optimal conditions of the effect of pH, TBRC, DATF, and OX concentrations. Central composite experimental design (CCD) with response surface and optimization was used to predict the photopotential, photocurrent, Ppp and η. Statistical analysis of variance (ANOVA) was carried out to identify the adequacy of the developed model and revealed good agreement between the experimental data and proposed model. The observed R2 value, adj. R2, pred. R2, and “F-values” indicate that the developed models are significant.

Synthesis of ZnFe2O4@Uio-66 nanocomposite for the photocatalytic degradation of metronidazole antibiotic under visible light irradiation.

The online version contains supplementary material available at 10.1007/s40201-021-00713-x.

Prevalence of electronegative electroretinograms in a healthy adult cohort

ObjectiveAn electronegative electroretinogram (ERG) can indicate important ocular or systemic disease. This study explored the prevalence of electronegative responses to dark-adapted stimuli in a largely healthy cohort.Methods and Analysis211 participants...

Is white the right light for the clinical electrooculogram?

To investigate if a lower luminance monochromatic LED stimulus could be used as an alternative to a high luminance white light for the clinical electrooculogram. Clinical electrooculograms were recorded in color normal participants (N = 23) aged 22.6 ± 1.2years, 7 male and 16 female using the standard 100cd.m-2 white illuminant and four monochromatic LEDs with peak wavelengths of 448, 534, 596 and 634nm at 30cd.m-2. Pupils were dilated and there was a 30cd.m-2pre-adaptation to white light for 2min followed by 15min dark adaptation and 20min recording in the light stimulus using a Ganzfeld stimulator. The normalized LP:DTratio for the short wavelength LED (448nm) was equivalent in amplitude and timing to the ISCEV standard EOG (p = .99). The LP:DTratio for the white (100cd.m-2) and 448nm (30cd.m-2) were (median ± SEM): 2.49 ± .11 and 2.47 ± .11. The time to light-rise peak was also equivalent being 9.0 ± .2 and 8.0 ± .4min (p = .54). Consideration may be given to using a short wavelength monochromatic stimulus that is more comfortable for the subject than the current 100cd.m-2 illuminant.

Protective roles of ketamine and xylazine against lightinduced retinal degeneration in rats

Purpose: To study the protective effects of ketamine and xylazine against light exposure-induced retinal degeneration (RD) in rats.&#x0D; Methods: Sprague Dawley rats were divided into three groups viz: light damage before anesthesia (LAE), light damage only (LDO), and control (CON) group which was kept in the dark for 12 - 18 h to habituate before light exposure. LDO group was exposed to light before anesthesia, while LAE group was maintained under anesthesia with ketamine and xylazine. The groups were kept for 120 min in darkness after anesthesia prior to light exposure and they were awakened prior to light damage. Functional assessment was carried out using electroretinography while morphological analysis was carried out using histology and immunochemistry techniques.&#x0D; Results: Ketamine-xylazine combination preserved the function of the retina and protected against light-induced RD based on retinal imaging studies and immunochemistry analysis. Xylazine and ketamine anesthesia provided protection against light-induced retinal damage, and thus reduced photoreceptor cell death.&#x0D; Conclusion: These results indicate that xylazine and ketamine anesthesia offer protection against lightinduced damage and photoreceptor cell death in rats, and therefore, can potentially be developed for use in humans.

Highly efficient and morphology dependent antibacterial activities of photocatalytic CuxO/ZnO nanocomposites

This study reports on morphology dependent antibacterial activities of CuxO/ZnO nanocomposites towards Escherichia coli. The CuxO/ZnO nanocomposites were formed by aqueous photoreduction of CuxO nanostructures on solution grown ZnO nanorods on Si substrates. By controlling the photoreduction time and temperature, various CuxO nanostructures including nanocubes, nanoclusters, nanospikes, and nanowebs were created as verified by scanning electron microscopy. X-ray diffraction analysis reveals the good crystallinity of the ZnO nanorods. X-ray photoelectron spectroscopy confirms the successful deposition of CuO and Cu2O nanostructures on the nanorods. Antibacterial tests were performed in dark and under low-intensity blue-light irradiation. The nanoweb sample has an antibacterial efficiency of 95.8% for 10 min in dark and the nanospike sample has an efficiency of 99.5% for 10 min under light. For the nanospike sample, remarkable bacterial survival ratios of 3 × 10–4 and 10–5 in dark and under light both for a 60 min reaction time, respectively, have been achieved. The excellent antibacterial performance is attributed to combined effects of mechanical piercing of ZnO nanorods, release of Zn2+, Cu2+, and Cu+ ions, and effective generation of reactive oxygen species due to charge separation.

Rapid bleaching of photoelectrochromic device by the simple addition of Pt catalyst in WO3 layer

We have developed a transparent conducting oxide (TCO) free photoelectrochromic device with fast kinetics. The device can be colored fully in 3 min and bleach 95% within 30 min in dark. The addition of Pt catalyst in the WO3 layer catalyzes the back reaction in dark. The coloring is not affected by the addition of catalyst on the WO3 layer and the device shows the same amount of coloring as in the reference device. Both devices took 3 min to color completely but bleaching time was improved by a large margin. The reference device which does not have any Pt in WO3 or TiO2 layer takes 24 h to bleach fully compared to 30 min bleaching of Pt added device. The commercial feasibility of the device was checked by making a large area (60x48 cm2) prototype Further the thermal stability of the device was checked by keeping it under thermal stress at 65 °C. It was observed that the device was stable after 300 h. This device paves the way for commercializing the photoelectrochromic windows without the use of external power and transparent conducting oxide.