Photodegradation Performance Research Articles

Thermal kinetics and photodegradation performance towards methylene blue of melt-quenched Se70Te30 glass

Abstract This paper reports the structure, basic characteristics, photocatalytic performance, and crystallization kinetics of the Se70Te30 glass. The Se70Te30 glass was synthesized using the melt-quenching method. The crystallization kinetics were investigated under non-isothermal condition via the differential scanning calorimetry (DSC) technique. For example, the glass transition activation energy, the thermal stability, and the Avrami index have been determined and discussed. It was found that thermal stability and glass-forming ability influence the crystallization rate. Furthermore, the activation energy needed for the amorphous-crystalline transition of the Se70Te30 glass was obtained using conventional methods. The thermal kinetic parameters were analyzed using various conventional approaches and were revealed to be influenced by the heating rate (β). The photocatalytic activity of the Se70Te30 glass towards methylene blue (MB) was examined and compared to the literature. The UV-visible irradiation time affects the photodegradation of MB and reaches 72.13% under the UV-visible irradiation for 70 min. A hypothesized mechanism for the degradation of the MB dye by Se70Te30 catalysts is described. The study employed Langmuir–Hinshelwood kinetics to ascertain the rate constant of 2.1 × 10–2 min–1 towards MB dye degradation and to assess the photo-reactivity of the Se70Te30 glass under investigation using quantitative analysis. The synthesized Se70Te30 glass could be helpful for purifying wastewater and degrading other organic dyes, in addition to its benefits for phase change memory applications.

Novel polyvinyl alcohol-assisted MnO2-ZnO-CuO nanocomposites as an efficient photocatalyst for methylene blue degradation from wastewater.

Pristine ZnO (Z), MnO2 (M), CuO (C) photocatalysts and polyvinyl alcohol (PVA)-assisted MnO2-ZnO-CuO (MZC) nanocomposites were synthesized via the sol-gel method. The synthesized samples were characterized using thermal analysis (TGA), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The thermal analysis results of the prepared nanomaterial confirmed that the suitable calcination temperature for the synthesis of these nanomaterials is 420 °C. In addition to the morphological and elemental composition, the characteristic diffraction peaks of the MZC nanomaterial were found to align with those of the pristine Z, M, and C photocatalysts. The photocatalytic activities of the synthesized nanomaterials for methylene blue (MB) degradation were evaluated under optimized conditions. The degradation efficiencies of Z, M, C, and MZC were found to be 45%, 57%, 66%, and 93%, respectively, for MB in 180 minutes. The MZC nanocomposite exhibited superior photocatalytic activity compared to the pristine materials, which is attributed to the synergetic effect of the Z, M, and C photocatalysts. The effects of pH, initial dye concentration, and catalyst load were also explored to determine the optimum conditions. The best photocatalytic efficiency was observed at pH 8, with a 130 mg L-1 catalyst load, and a 10 mg L-1 initial dye concentration. The efficiency of the MZC nanocomposite in real textile wastewater was also tested, achieving 80% degradation of pollutants within 180 minutes. Recycling experiments were conducted for four consecutive cycles under optimal conditions. The photodegradation efficiency for the first, second, third, and fourth cycles was 93%, 91%, 90%, and 89%, respectively, demonstrating high consistency in photodegradation performance across the four cycles. Moreover, a Z-scheme photocatalytic mechanism was proposed as a potential mechanism for the MZC photocatalytic system.

Synthesis of silver-decorated titanium dioxide nanostructured films for enhanced visible light photocatalysis

Titanium dioxide (TiO2) has been extensively investigated for applications in photocatalysis due to its stability, nontoxicity, and robust photocatalytic properties. Although thin films of TiO2 are effective in wastewater treatment, their dense structure limits surface accessibility. The oblique angle deposition (OAD) technique can be used to create high surface area nanostructured thin films essential for photocatalytic applications. In this study, OAD was used to grow TiO2 thin films. To extend the activity to the visible light region, plasma-reduced silver (Ag) particles were coupled to the TiO2 surface. The Ag-decorated TiO2 (Ag-TiO2) nanostructured films were fabricated using a custom-built magnetron sputter deposition system with OAD technique capability. Different substrate angles of 0°, 35°, and 70° with respect to the target normal were used. The films were characterized for their structural, compositional, and optical properties. The photodegradation performance was evaluated using methylene blue (MB) as the test analyte under visible light irradiation. The results showed a significant improvement in degradation efficiency using plasma-reduced Ag-TiO2. Substrates tilted at 70° achieved the highest MB degradation efficiency of 89.84% after 5 h exposure. This tilt angle also revealed high surface roughness and high surface area. By tilting the substrate with respect to the target, high surface area thin films can be fabricated. This technique is ideal for applications that depend on the area of contact, such as photocatalysis.

Molecular engineering of perylene diimide polymers to enhance photocatalytic performance for efficient photodegradation of ofloxacin

Molecular engineering of perylene diimide polymers to enhance photocatalytic performance for efficient photodegradation of ofloxacin

Machine learning predictive model to estimate the photo-degradation performance of stannates and hydroxystannates photocatalysts on a variety of waterborne contaminants

In this work, a comprehensive machine learning (ML) methodology was used to predict the degradation efficiency of different stannate and hydroxystannate photocatalysts on a wide range of waterborne pollutants. The structural, atomic features along with molecular fingerprints (MF) were used as descriptors of the crystalline phase of the photocatalysts and the organic compounds, respectively. The encoded features of the photocatalysts and contaminants along with the experimental variables of the degradation process are input to two ML models, named as RF (random forest) and KNN (K nearest neighbor). The RF model has achieved a very good prediction of the photocatalytic degradation efficiency (%) by different photocatalysts over a wide range of organic contaminants. The RF model performance was investigated by applying two different training strategies. The effects of different factors on photocatalytic degradation performance are further evaluated by feature importance analyses. Two illustrative applications on the use of the ML model for optimal photocatalyst selection and for assessing other types of photocatalysts for different environmental applications were provided.

Modification of bismuth-rich to synthesize floral spherical Z-type heterojunction CoAl2O4/Bi4O5Br2 photocatalysts for photocatalytic degradation of tetracycline: DFT calculations, toxicity assessment

Strategies were employed to boost responsiveness to visible light to augment the elimination of water-borne organic contaminants and mitigate the recombination of electron-hole pairs. Herein, a floral spherical CoAl2O4/Bi4O5Br2 Z-scheme heterojunction was effectively produced through in-situ construction, followed by an evaluation of its photocatalytic activity against tetracycline hydrochloride. The best-prepared photocatalyst CoAl2O4/Bi4O5Br2 showed good photodegradation performance (91.5%) under visible light. In addition, it exhibits good removal efficiency for other antibiotics and dyes, and the prepared catalyst demonstrates favorable stability. The accomplishment of fabricating the CoAl2O4/Bi4O5Br2 heterojunction, along with the photogenerated carrier relay mechanism conforming to a Z-scheme process, was substantiated through a variety of analytical techniques and DFT calculations. Within the engineered Z-scheme heterojunction of CoAl2O4/Bi4O5Br2, an intrinsic electric field facilitates the direct shuttling of photo-induced charges from Bi4O5Br2's conduction band to CoAl2O4's valence band. Simultaneously, this electric field formation serves to diminish the recombination rate of electrons and holes. Finally, possible degradation pathways were proposed, and the intermediates were evaluated for toxicity. The results indicate that the construction of CoAl2O4/Bi4O5Br2 heterojunction is a feasible pathway for the effective degradation of antibiotics.

Preparation of Biochar-Loaded Er3+-Doped BiOCl Ultrathin Nanosheets Composite Photocatalysts and Their Photodegradation Performance of TC-HCl

In this study, biochar-loaded E3+:BiOCl (C/3E3+:BiOCl) was synthesized with varying levels of E3+ doping using a one-step solvothermal method and used for tetracycline hydrochloride (TC-HCl) degradation. Their structure, shape and morphology were not only characterized by power X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) but also by UV-vis diffuse reflectance spectra and upconversion (UC). The results indicated a significant enhancement in the photocatalytic activity of the catalyst following the introduction of Er3+. The composite material C/3E3+:BiOCl, with a doping concentration of 3 mol%, demonstrated the highest photocatalytic activity, achieving an impressive visible light degradation efficiency of 89.2% for TC HCl within 90 min. This marks an increase of 33.5% compared to the BiOCl monomer and 17.4% compared to C/BiOCl. Additionally, when exposed to light with wavelengths exceeding 600 nm, C/3E3+:BiOCl maintained a photodegradation efficiency of 44.3%, while BiOCl and C/BiOCl showed no photocatalytic activity under the same conditions. This finding highlights the effectiveness of BiOCl as a doping matrix, which enhances the photocatalytic performance of BiOCl through the upconversion effect of E3+ and the electron transfer mechanisms associated with biochar.

Ibuprofen photodegradation promoted by ZnO and TiO2-P25 nanoparticles: A comprehensive kinetic, reaction mechanisms, and thermodynamic investigation

Photocatalytic activity, reaction kinetics, modeling, and thermodynamics of commercial TiO2-P25 and ZnO nanoparticles (NPs) for ibuprofen (IBU) photodegradation were investigated. Photodegradation experiments were performed in a batch reactor under UV irradiation. The photodegradation performances of TiO2-P25 and ZnO NPs were further studied and modeled under different operation conditions, by varying the reaction temperature, catalyst bulk density, and the initial concentration of the IBU solution. The descriptive kinetic models for the experimental data were tested, through the estimated kinetic parameters, together with the statistical information, revealing that the reaction rate in the case of TiO2-P25 is of first order while the ZnO NPs follow second-order kinetics with respect to IBU. The photodegradation mechanisms for both TiO2-P25 and ZnO NPs were determined to be Langmuir-Hinshelwood and Eley-Rideal, respectively. Thermodynamic parameters were assessed, particularly, changes in Gibbs free energy, enthalpy, and entropy indicating the efficient photodegradation performance of these NPs.

Elaboration and Characterization of Different Zirconium Modified ETS Photocatalysts for the Degradation of Crystal Violet and Methylene Blue.

In this study, Zirconium-modified Engelhard Titanium Silicate 4 (Na-K-ETS-4/xZr) catalysts were synthesized and evaluated for their photocatalytic efficiency in degrading crystal violet (CV) and methylene blue (MB) in aqueous solutions. The catalysts were characterized using XRD, FTIR, SEM, WDXRF, and nitrogen adsorption/desorption isotherms. The results confirmed the successful incorporation of Zr into the ETS-4 framework, with the highest Zr content reaching 9.2 wt %. The photocatalytic performance under visible light irradiation was studied at varying pH levels. The Na-K-ETS-4/6.3Zr catalyst exhibited the highest photodegradation efficiency for CV (76.6 %), while Na-K-ETS-4/8.9Zr achieved 86.6 % efficiency for MB. A combination of Engelhard Titanium Silicate 10, Na-K-ETS-10/6.3Zr and Na-K-ETS-4/8.9Zr significantly enhanced dye degradation, achieving up to 96.5 % efficiency for MB. Kinetic studies indicated that the degradation process follows a non-linear pseudo-first-order model. The catalysts also demonstrated excellent reusability, with minimal efficiency loss after five cycles, and full recovery after an ethanol wash. These findings suggest that Na-K-ETS-4/xZr is a promising candidate for environmental water treatment applications due to its efficient photodegradation performance and stability.

Porphyrin-prompted robust lead-free cesium bismuth bromide for efficiently photodegrading antibiotics pollutants in water

The lead-free halide perovskite represented by Cs3Bi2Br9 (CBB) has attracted intense attention as an environmentally friendly alternative for toxic lead halide perovskite (CsPbBr3). However, the limited light absorption and instability of Cs3Bi2Br9 hinder its practical application in photocatalysis. In this work, Cs3Bi2Br9 nanosheets was modified with bifunctional porphyrin (CBB-TCPP) displayed enhanced visible light absorption properties and promising water stability. The CBB-0.5TCPP shows a sharply improved photodegradation performance of 84 % in 60 min in water and demonstrating the outstanding cycling stability. Furthermore, photoelectrochemical tests suggested that the charge separation and transfer properties of the modified perovskite materials were significantly improved compared with the pristine CBB. The CBB-0.5TCPP exhibited an impressive photogenerated carrier separation efficiency of 90.74 %. This work innovatively proposes a new way to modify perovskite with double duty by boosting stability and optimizing light absorption properties.

Effect of synthesis temperature on the properties and photocatalytic performance of peroxo-titanate nanotubes prepared by bottom-up synthesis method

The alkaline treatment synthesis of titania/titanate nanotubes (TNTs) requires highly concentrated alkaline solutions (≥ 10 mol/L), which pose environmental and productivity limitations. In contrast, a bottom-up synthesis method for peroxo-titanate nanotubes (PTNTs) has been developed. This method offers two advantages: it can synthesize materials using low-concentration alkaline solutions (1.5 mol/L) and produce photocatalytic materials that are responsive to visible light. In general, the higher the crystallinity of a catalyst, the better its properties. However, PTNTs synthesized at temperatures close to their boiling point (around 100 °C) exhibit low crystallinity. This study hypothesizes a hydrothermal synthesis method at higher temperatures will enhance the crystallinity and photocatalytic performance of PTNTs, synthesizing them at temperatures ranging from 120 to 200 °C using a method capable of exceeding the boiling point. Higher synthesis temperatures resulted in improved morphological and crystallographic properties of the PTNTs. However, the formation of peroxo-bonding, crucial for visible light responsiveness, decreased. Nevertheless, peroxo-bonding formation was still achievable at the highest temperature of 200 °C, and the sample exhibited the best Rhodamine B (Rh B) photodegradation performance under visible light due to its enhanced specific surface area and crystallinity. This study highlights the novelty and environmental significance of hydrothermally synthesized PTNTs as superior photocatalysts by optimizing the synthesis temperature while using lower concentration alkaline solutions.

Facile synthesis of CQD/g-C3N4 as a highly effective metal-free photocatalyst for the degradation of carmoisine and indigo carmine dye

The development of extensive dye pollution in the water ecosystem seriously endangers the health of the living organism. For effectively eradicating dyecontaminants from water bodies, photocatalysis is consideredan effective, energy-consumption, inexpensive disinfection technique. As an alternative to conventional metal-based catalysts, heterogeneous metal-free photocatalysts are more sustainable and kinder to the environment. Here, we reported the simplehydrothermalchemical production of Carbon Quantum dots (CQD)-doped graphitic carbon nitride(GCN). Analytical instruments such as XRD, SEM, FE-SEM, HR-TEM, EDX, FT-IR, thesurface area of BET analysis, photoluminescence, and UV–vis spectroscopy, zeta potentialwere used to characterize the as-prepared CQD doped GCN (CDCN). The degradation studies reveal that the CDCN catalyst displays the highest rate of degradation performance than pure GCN. Within 60 min, it shows 96 % degradation toward indigo Carmine (IC) and 93 % decomposition towards carmoisine dye (CM). Significant e−/h+ separation, an increased surface area, and a high redox potential capacity to induce charge bears may all contribute to the CDCN catalyst’s enhanced photocatalytic degradation efficiency. The efficiency of the photocatalytic process was optimized by studying and altering many variables. These include Dye concentration, catalyst concentration, and variation of the pH solution were some of these. The nanocomposite exhibited excellent stability after three successive runs of the photocatalytic procedure. According to the kinetics analysis results indicate that the photocatalytic decomposition of Indigo Carmine (IC) and carmoisine (CM) dye follows pseudo-first-order kinetics. For better photodegradation performance, a potential photocatalytic method employing several pairs of electron-hole acceptor scavengershas been put forth. Based on the positionsof the band gap and the result of the characterization, a feasible mechanismpathway for charge carriers was also presented.

Stabilize the oxygen vacancies in 2D bipyramidal CoFe2O4 via altering local electronic structure by SnSe for boosted photocatalytic degradation of ciprofloxacin: Interfacial engineering, mechanism insight and toxicological evaluation of byproducts

Investigating a cost-effective, environmentally friendly, and improved photocatalysis system for ciprofloxacin (CIPRO) degradation presents a significant hurdle in environmental remediation. In this work, SnSe nanoparticles (NPs) were synthesized by hydrothermal approach leading to the successful formation of SnSe-CoFe2O4 nanocomposite (SCF NCs). It was achieved by decorating the surface of SnSe NPs with 2D bipyramidal oxygen-vacant (OV) CoFe2O4 NPs. This work aims to stabilize the OV in 2D bipyramidal CoFe2O4 by altering the local electronic structure through SnSe, enhancing the photocatalytic degradation of CIPRO. The NPs surface morphological features, high crystalline nature, and enhanced surface area properties are investigated using several characterization techniques. The X-ray photoelectron spectroscopy (XPS) reveals the oxygen defect site in CoFe2O4 and the interfacial electric field between SnSe and CoFe2O4 NPs, significantly improving the catalytic activity of SCF NCs. The degradation of CIPRO at the optimized concentration (50 mg/L – SCF NCs, 10 mg/L CIPRO, pH - 3) under visible light reached around 91.3%. The SCF NCs demonstrate superior photodegradation performance of 2.59 and 1.86 times greater activity compared to their individual counter parts, SnSe and CoFe2O4, respectively. Furthermore, the system accommodates a broad range of degradation concentrations of CIPRO from 5 – 25 mg/L, indicating promising potential for practical applications. Additionally, the intermediate compounds formed during the photodegradation process were analyzed using gas chromatography-mass spectrometry (GC-MS), and a possible degradation pathway was proposed. The toxicity levels of these intermediates were assessed in various aquatic organisms, including fish, daphnia, and green algae using the ecological structure activity relationship (ECOSAR) tools. This research presents a new perspective on the development of innovative materials for the removal of pollutants from water sources.

Shining light on broad-spectrum responded NaYF4:Yb,Er,Tm@Bi@BiOI: Understanding the enhanced photodegradation performance of bisphenol A and mechanisms

This work reported a novel ternary heterogeneous photocatalyst NaYF4:Yb,Er,Tm@Bi@BiOI (NBEG-6h). NBEG-6h exhibits broad-spectrum absorption from ultraviolet to near-infrared. The elimination efficiency of BPA by NBEG-6h under simulated sunlight and near-infrared light irradiation was 88% (24 min) and 93.9% (160 min), respectively. It also has the universality of degrading various pollutants, good reusability and stability. The exceptional photocatalytic activity can be attributed to the absorption of near-infrared light by NaYF4:Yb,Er,Tm, which improves the total efficiency of sunlight utilization. The localized surface plasmon resonance effect of Bi nanoparticles enhances the light absorption performance of the heterostructure. Furthermore, combining Bi and BiOI accelerates carrier migration and improves the separation efficiency of photogenerated electron-hole pairs. h+, ·O2− and 1O2 play the pivotal roles during the photocatalytic process. This research offers new insights into the design, development, and mechanism understanding of full-spectrum-driven heterostructure photocatalysts. It provides an environmentally sustainable approach to the treatment of harmful organic pollutants.

Development of flexible and mesoporous CdS/ZnS/PVDF nanocomposites with remarkable organic dye degradation performance under natural sunlight

The engineering of polymer-based nanocomposites is a highly promising strategy for improving both the efficiency and stability of catalysts used in wastewater treatment. In this work, we explore the efficacy of flexible CdS/ZnS/PVDF nanocomposite films towards degradation of Malachite Green dye under low energy visible light and ambient sunlight. Films with varying weight percentage of CdS/ZnS nanofillers (0 %, 5 %, 10 %, 15 %, 20 %) were successfully prepared by solution casting method and the physiochemical properties were characterized using various techniques such as XRD, SEM, AFM, EDX, BET, UV–Vis DRS and FTIR. Pore diameter of 5.5 nm was observed, indicating that CdS/ZnS is mesoporous in nature. Under the optimum photocatalytic condition of 15 ppm dye concentration and pH 9, 15 wt% CdS/ZnS/PVDF showed the maximum photodegradation efficiency of 93.5 % in 30 min. The sample exhibited excellent reusability for five consecutive runs of the experiments which show a degradation percentage of 92.1 % in the fifth run and the scavenging study established that superoxide radicals play the major role in the photodegradation process. The experiments under natural sunlight on three separate days showed a remarkable photodegradation performance of 89 %, 93.4 % and 93.6 % highlighting the potential of CdS/ZnS/PVDF nanocomposites for sustainable wastewater treatment under natural sunlight.

Effective strategy for C3N5 with improved photodegradation performance: The key role of the robust built-in electric field and enhanced oxygen adsorption capacity

Effective strategy for C3N5 with improved photodegradation performance: The key role of the robust built-in electric field and enhanced oxygen adsorption capacity

Highly efficient Zn(O,S)/Mo(O,S)2 oxysulfide heterostructure photocatalyst for organic pollutant degradation

Environment and energy are presently some of the highest priority topics for mankind that need to be addressed. Organic pollutants are toxic and carcinogenic for human and aquatic life hence their presence in water even in low concentrations can cause serious health problems. Photodegradation of organic pollutants by utilizing oxide-based heterostructure photocatalysts is the promising approach to carry out remediation efficiently ascribed to the advanced optoelectronic and structural superiority of oxide photocatalysts. The Zn(O,S)/Mo(O,S)2 composites were synthesized via a facile solvothermal method at low temperatures. Several methods were used to characterize the composite morphology, structure, electrical conductivity, chemical composition, and optical characteristics. The heterostructured Zn(O,S)/Mo(O,S)2 oxysulfide was employed successfully in the photocatalytic degradation of organic pollutants. Among the as-prepared samples, the 30-ZnMoOS composite catalyst was found to have the highest photodegradation performance on various organic dye pollutants. The photocatalytic activity of the as-synthesized Zn(O,S)/Mo(O,S)2 samples was assessed on the photodegradation of different kinds of organic dyes under visible light irradiation. The photocatalytic degradation efficiency of 30-ZnMoOS composite over 10 ppm neutral red (NR), methylene blue (MB), rhodamine B (Rh B), and methyl orange (MO) was found to be 99.6 %, 99.9 %, 99.5 %, and 98.8 % within 40, 45, 180, and 180 min, respectively, under visible light illumination. In the present photocatalytic system, the superoxide (.O2-) anions, hydroxyl (.OH) radicals, and holes (h+) are proposed to be the direct reactive species causing the photodegradation of organic dyes.

Enhancement of the photodegradation performance towards methylene blue and rhodamine B using AgxSn1–xO2 nanocomposites

In the present study, the structural properties, as well as the photodegradation performance of methylene blue (MB) and rhodamine B (Rh B) using hydrothermal synthesized AgxSn1–xO2 (0 ≤ x ≤ 1) nanocomposites were studied. The study was investigated using various techniques including EDS, XRD, FE-SEM, HR-TEM, photoluminescence spectroscopy, N2 adsorption-desorption, GC-MS, and a double-beam spectrophotometer. The tetragonal SnO2 phase dominates, while the cubic Ag2O phase appears at larger x ratios (x ≥ 0.5). The crystallite and particle sizes were slightly raised for a low Ag ratio but dramatically increased for higher x ratios. Different morphologies emerge depending on the composition, such as spherical and irregular particles for x = 0 and 1, sheet-like morphology for x = 0.05, 0.2, and 0.4, and worm-like morphology for x = 0.5. The maximum surface area was calculated using the BET method to be 358 and 354 m2/g for x = 0.2 and 0.4, respectively. The direct optical band gap depends on the x ratio and the crystallite size and equals 3.95 eV and 3.70 eV for x = 0 and x = 1, respectively. The synthesized AgxSn1–xO2 composites demonstrated excellent photodegradation efficiency (η) towards MB and Rh B. The majority of compositions had high η towards MB and the highest value of 99.6 % was attained using Ag0.4Sn0.6O2 under the UV–visible irradiation for 1.5 h. Also, synthetic composites demonstrated efficient photodegradation of Rh B, particularly for higher Ag content (η = 94.4 % at x = 0.5). The catalysts revealed acceptable reusability and stability, and the degraded products were studied using the GC-MS technique with a proposed mechanism of degradation. The improvement in photodegradation of MB and Rh B dyes can be attributed to an increase in surface area, as well as the development of shape and optical characteristics.

Enhanced photodegradation of organic dyes using copper and zinc aluminate nanophotocatalysts

This study aims to enhance the photocatalytic efficiency of CuxZn1-xAl2O4 (x = 0.0, 0.2, 0.4, 0.6, and 0.8) nanophotocatalysts synthesized via a sol-gel self-combustion method. Rietveld analysis confirmed the formation of single-phase spinels with a face-centered cubic structure and Fd-3m space group symmetry, while electron density distribution analysis supported the ionic character of bonding within the material. Subsequent UV–visible spectroscopy revealed that the addition of Cu(II) reduced the band gap from 4.66 eV to 2.54 eV, facilitating enhanced light absorption. Consequently, the catalyst with x = 0.8 deteriorated 95 % of methyl orange (MO) and 93 % of rhodamine-B (RhB) in 120 min of visible light irradiation, following a pseudo-first-order kinetic model. The Cu0.8Zn0.2Al2O4 sample demonstrated significant reusability and stability, with degradation rates of 93–79 % for RhB and 95–81 % for MO after four cycles. Scavenging studies indicated that photoexcited holes (h), hydroxyl radicals (OH•), and superoxide radicals (O₂•⁻) were key factors in the degradation process. This study presents an improved approach for enhancing the photodegradation performance of the Cu0.8Zn0.2Al2O4 catalyst for pharmaceutical and wastewater treatment applications.

Semiconductor Nanoporous Anodic Alumina Photonic Crystals as a Model Photoelectrocatalytic Platform for Solar Light‐Driven Reactions

In this study, nanoporous anodic alumina distributed‐Bragg reflectors (NAA–DBRs) functionalized with tungsten trioxide (WO3) are used as prototype photoelectrocatalysts (PEC) for harnessing the slow photon effect to maximize photon‐to‐electron conversion efficiency under UV–visible–NIR illumination. NAA–DBR structures are structurally engineered by anodization, where their characteristic photonic stopband is precisely tuned along specific positions of the UV–visible spectrum. Subsequent atomic layer deposition is employed to coat the inner surface of these porous structures with WO3 semiconductor layers. Upon the application of overpotential bias, these platforms reveal excellent electron–hole pair separation to boost photoelectrocatalytic reactions. Photoelectrochemical degradation of methylene blue is used as a model reaction to elucidate enhancements associated with structural and optoelectronic arrangements. Notably, precise spectral alignment between the photonic stopband's red edge and the absorbance band of methylene blue enhances the degradation performance through the slow photon effect. Applying an overpotential bias further improves the photodegradation performance through efficient charge separation. These systems outperform comparable structures in this model reaction, achieving a maximum kinetic rate of 13.7 ± 2.0 h−1. The findings create new opportunities to develop high‐performing PEC technologies harnessing light–matter interactions.