High Photocatalytic Efficiency Research Articles

Performance and Mechanism of Co and Mn Loaded on Fe- Metal-Organic Framework Catalysts with Different Morphologies for Simultaneous Degradation of Acetone and NO by Photothermal Coupling

VOCs can be used instead of ammonia as a reducing agent to remove NO, achieving the effect of removing VOCs and NO simultaneously. Due to the high energy consumption and low photocatalytic efficiency required for conventional thermocatalytic purification, photothermal coupled catalytic purification can integrate the advantages of photocatalysis and thermocatalysis in order to achieve the effect of pollutants being treated efficiently with a low energy consumption. In this study, samples loaded with Co and Mn catalysts were prepared using the hydrothermal method on Fe-MOF with various morphologies. The catalytic performance of each catalyst was analyzed by studying the effects of their physicochemical properties through various characterizations, including XRD, SEM, BET, XPS, H2-TPR, TEM and O2-TPD. The characterization results demonstrated that the specific surface area, pore volume, high valence Co and Mn atoms, surface adsorbed oxygen and the abundance of oxygen lattice defects in the catalysts were the most critical factors affecting the performance of the catalysts. Based on the results of the performance tests, the catalysts prepared with an octahedral-shaped Fe-MOF loaded with Co and Mn showed a better performance than those loaded with Co and Mn on a rod-shaped Fe-MOF. The conversions of acetone and NO reached 50% and 64%, respectively, at 240 °C. The results showed that the catalysts were capable of removing acetone and NO at the same time. Compared with the pure Fe-MOF without Co and Mn, the loaded catalysts showed a significantly higher ability to remove acetone and NO simultaneously under the combination of various factors. The key reaction steps for the catalytic conversion of acetone and NO on the catalyst surface were investigated according to the Mars–van Krevelen (MvK) mechanism, and a possible mechanism was proposed. This study presents a new idea for the simultaneous removal of acetone and NOx by photothermal coupling.

Rapid Exciton Dissociation and Charge Transfer Endowed by Reinforced Interfacial Interaction in a Mixed-Dimensional 2D/3D Heterojunction Nanocatalyst for High-Efficiency Photocatalysis

Rapid Exciton Dissociation and Charge Transfer Endowed by Reinforced Interfacial Interaction in a Mixed-Dimensional 2D/3D Heterojunction Nanocatalyst for High-Efficiency Photocatalysis

Accessible New Non-Quantum Dot Cs2PbI2Cl2-Based Photocatalysts for Efficient Hole-Driven Photocatalytic Applications

Efficient, low-cost photocatalysts with mild synthesis conditions and stable photocatalytic behavior have always been the focus in the field of photocatalysis. This study proves that non-quantum-dot Cs2PbI2Cl2-based materials, created by a simple method, can be successfully employed as new high-efficient photocatalysts. The results demonstrate that two-dimensional Cs2PbI2Cl2 perovskite can achieve over three times higher photocatalytic performance compared to three-dimensional CsPbBr3 perovskite. Moreover, the photocatalytic performance of Cs2PbI2Cl2 can be further improved by constructing a heterojunction structure, such as Cs2PbI2Cl2/CsPbBr3. Cs2PbI2Cl2 can connect well with CsPbBr3 through a simple method, resulting in tight bonding at the interface and efficient carrier transfer. Cs2PbI2Cl2/CsPbBr3 exhibits notable 5-fold and 10-fold improvements in photocatalytic performance and rate compared to CsPbBr3. Additionally, Cs2PbI2Cl2/CsPbBr3 demonstrates superb stable catalytic performance, with nearly no decrease in photocatalytic performance after 7 months (RH = 20% ± 10, T = 25 °C ± 5). This study also reveals that the photocatalytic process based on Cs2PbI2Cl2/CsPbBr3 can directly oxidize organic matter using holes, without relying on the generation of intermediate reactive oxygen species from water or oxygen (such as ·OH or ·O2−), showcasing further potential for achieving high photocatalytic efficiency and selectivity in anhydrous/anaerobic catalytic reactions and treating recalcitrant pollutants.

Accessible New Non-Quantum Dot Cs2PbI2Cl2-Based Photocatalysts for Efficient Hole-Driven Photocatalytic Applications

Efficient, low-cost photocatalysts with mild synthesis conditions and stable photocatalytic behavior have always been the focus in the field of photocatalysis. This study proves that non-quantum-dot Cs2PbI2Cl2-based materials, created by a simple method, can be successfully employed as new high-efficient photocatalysts. The results demonstrate that two-dimensional Cs2PbI2Cl2 perovskite can achieve over three times higher photocatalytic performance compared to three-dimensional CsPbBr3 perovskite. Moreover, the photocatalytic performance of Cs2PbI2Cl2 can be further improved by constructing a heterojunction structure, such as Cs2PbI2Cl2/CsPbBr3. Cs2PbI2Cl2 can connect well with CsPbBr3 through a simple method, resulting in tight bonding at the interface and efficient carrier transfer. Cs2PbI2Cl2/CsPbBr3 exhibits notable 5-fold and 10-fold improvements in photocatalytic performance and rate compared to CsPbBr3. Additionally, Cs2PbI2Cl2/CsPbBr3 demonstrates superb stable catalytic performance, with nearly no decrease in photocatalytic performance after 7 months (RH = 20% ± 10, T = 25 °C ± 5). This study also reveals that the photocatalytic process based on Cs2PbI2Cl2/CsPbBr3 can directly oxidize organic matter using holes, without relying on the generation of intermediate reactive oxygen species from water or oxygen (such as ·OH or ·O2−), showcasing further potential for achieving high photocatalytic efficiency and selectivity in anhydrous/anaerobic catalytic reactions and treating recalcitrant pollutants.

Improving charge separation capability of CdS/Bi/Ti3C2Tx nanocomposites for efficient photocatalytic oxidative organic transformations

The development of new strategies to improve the separation of photogenerated carriers is crucial for enhancing photocatalytic efficiency of heterogeneous photocatalysts. Here, we have successfully constructed CdS/Bi/Ti3C2Tx nanocomposites with high electron-hole separation efficiency through coupling Bi and Ti3C2Tx on CdS nanorods. The average emission lifetime of the CdS/Bi/Ti3C2Tx nanocomposites can be up to ca. 6.74 ns, which realizes efficient heterogeneous photocatalysis for oxidative hydroxylation of arylboronic acids and coupling of amines with high yields. The photocatalytic rates are ∼15250 μmol·g−1·h−1 for 4-cyanophenol production and ∼12125 μmol·g−1·h−1 for (E)-N-benzyl-1-phenylmethanimine production, which are twice and three-fold higher than those (∼7500 and ∼4000 μmol·g−1·h−1) of the CdS nanorods, respectively. The high photocatalytic efficiency can be ascribed to the strong electron-hole separation capacity by migrating electrons into Bi and Ti3C2Tx from CdS nanorods. In addition, the CdS/Bi/Ti3C2Tx nanocomposites also have satisfactory sustainable recycling and reuse properties. This work provids a new strategy for constructing heterogeneous metal/semiconductor nanophotocatalysts with strong electron-hole separation capacity for high-efficient light-driven organic transformations.

Stable loading of MOF-derived carbon skeleton encapsulated Ni and BiOBr on carbonized cellulose fibers for fabricating high-performance and recyclable photocatalytic paper

The highly dispersed small-size metal co-catalysts can effectively improve the photocatalytic efficiency of semiconductor photocatalysts by separating photogenerated electrons and enriching active sites. However, this system tends to aggregate in the absence of carrier, resulting in the decrease of active sites. Here, MOF-derived carbon skeleton (MDCS) encapsulated Ni nanoparticles (Ni@MDCS) and BiOBr was loaded onto carbonized cellulose fibers (CCF) with the help of polydopamine (PDA) to construct high-performance and recyclable photocatalytic paper for photocatalytic degradation of organic dyes in water. The characterization results showed that MDCS promoted good dispersion of Ni nanoparticles and provided sufficient active sites. And Ni@MDCS as a co-catalyst accelerated the separation of photogenerated carriers in BiOBr. The PDA improved the loading state of Ni@MDCS on CCF and converted into N-doped C in the carbonization process for further increasing the transfer efficiency of photogenerated electrons. In the composite paper, the stable loading of Ni@MDCS/BiOBr hybrid on CCF improved the dispersion and reusability of photocatalyst. The degradation rate of rhodamine B on CCF/PDA-C/Ni@MDCS/BiOBr paper was as high as 94.6 % after 60 min visible light irradiation, which was about 2.5 times higher than that of CCF/BiOBr paper. During 10 cycles, CCF/PDA-C/Ni@MDCS/BiOBr paper maintained high photocatalytic efficiency and good structural stability. This study provides a new way for developing high-performance and recyclable photocatalytic paper.

A comparative study of metal-sulphide/ZnO for visible-light-induced photocatalysis and the six-flux photon absorption model of an external lamp photoreactor

This study compares the photocatalytic performance of three metal-sulphide/ZnO nanocomposites (Ag2S/ZnO, FeS/ZnO and NiS/ZnO) for degrading tetracycline (TC) under visible light irradiation. The nanocomposites were synthesized using a novel one-pot solid-phase combustion method, analysed by various characterization techniques (XRD, SEM, TEM, BET, FTIR, PL, and UV–vis DRS). Photocatalytic tests revealed significantly higher efficiencies for Ag2S/ZnO (87.50 %), FeS/ZnO (80.53 %) and NiS/ZnO (77.27 %) nanocomposites exhibit much higher photocatalytic efficiency than pure ZnO (42.63 %). The improved performance is attributed to the reduced bandgap energy and suppressed electron-hole (e-/h+) recombination facilitated. This can also be attributed to the photocatalytic inhibition test which confirmed the holes (h+) as the main inhibitor and identified the superoxides (O2•−) radical as the main active specie responsible for the degradation. Additionally, this study innovatively applies the Six Flux radiation absorption-scattering models (SFM) to an external lamp photocatalytic reactor. This approach allows precise determination of reactor parameters and intrinsic reaction kinetics for TC degradation, independent of the radiation field. The TC degradation rate, calculated at 5.6 × 104EinL−1S−1 for every point in the reaction space, shows a half-order dependence on the local volumetric rate of photon absorption (LVRPA) of 142.3 W/m3, at a photon flux of 115.42 W/m2. These findings elucidate the mechanisms behind enhanced visible-light photocatalysis and demonstrate the innovative application of photon absorption and light-scattering models to optimize reactor design and efficiency. This work offers valuable insights for developing advanced photocatalytic systems with improved performance and practical applicability.

Crystal violet degradation by visible light-driven AgNP/TiO2 hybrid photocatalyst tracked by SERRS spectroscopy

Dyes are important concerns regarding aquatic environmental contamination given their extensive industrial use and the occurrence of highly toxic and carcinogenic effects on the biota. In this work, photodegradation processes of the organic dye crystal violet (CV) by a hybrid plasmonic photocatalyst involving titanium dioxide (TiO2) and silver nanoparticles (AgNP), through irradiation with low-power visible light were studied, and the experiments were tracked by ultraviolet-visible absorption (UV–VIS) and surface-enhanced resonance Raman scattering (SERRS) spectroscopies. Enhanced photocatalytic activity was observed, reaching about 71, 80 and 87 % of CV removal with only 100 minutes of irradiation, depending on the Ag loading used. The high photocatalytic efficiency is further highlighted by the low energy consumption in the process, requiring only ca. 1.46 kW h L-1 in the best reaction condition. Quantum-mechanical calculations were used to the assignment of electronic spectra, as well as to the prediction of frontier molecular orbitals and atomic charges, aiming to propose mechanisms for radical attacks. Such results allow suggesting degradation processes involved mainly N-demethylation and bond breaking of central carbon. The presence of CV protonated species was also supported through Density Functional Theory (DFT) investigation. The integration of theoretical and experimental results allows proposing the formation of pararosaniline, phenol and benzophenone derivatives, which may have highest ecotoxicity than the original contaminant, outstanding the remarkable relevance of SERRS spectroscopy in monitoring such recalcitrant substances.

Controllable construction of hollow Fe3O4/Ag particles for microwave absorption and photocatalysis

Hollow metallic composite particles are widely used in microwave absorption and catalysis due to their unique cavity structures, and favorable physical and electromagnetic properties. In this work, we propose an approach to prepare highly dispersed Fe3O4/Ag composite particles with a hollow structure using water-soluble green template method combined with in-situ growth process. The as-prepared cubic Fe3O4/Ag composite particles with an average size of 3.19 μm of hollow Ag and 11.65 nm of Fe3O4 coating on the surface were used as fillers for preparing microwave absorption epoxy resin films, showing a minimum reflection loss of −62.37 dB at 16.63 GHz with 7.5 mm thickness. An effective absorption bandwidth of 4.80 GHz can be observed in the frequency bands of 4.70–6.09 and 14.59–18.00 GHz. This mechanism is attributed to the internal cavity of the Fe3O4/Ag particles realizing multiple reflections of electromagnetic waves, and the synergistic effect of Fe3O4 and Ag. Moreover, this perspective is confirmed by their photocatalytic performance. The Fe3O4/Ag particles achieve a high photocatalytic degradation efficiency of 99.84% for Congo red dye within 30 min of light exposure and maintain a value of 96.62% after 6 cycles, demonstrating an outstanding reusability.

EXPLORING THE IN‐SITU DEVELOPMENT OF A 1D/2D GADOLINIUM IRON OXIDE/TUNGSTEN DISULFIDE PHOTOCATALYST TO IMPROVE TETRACYCLINE DEGRADATION MEDIATED BY VISIBLE LIGHT

In the field of photocatalysis, heterojunction photocatalysts have garnered a lot of attention due to their high‐efficiency interfacial charge‐transfer property and their nanoarchitecture. Herein, GdFeO3/WS2is successfully synthesized by the in‐situ growth method and holds significant catalytic properties and efficient degradation for tetracycline. Using WS2 as a co‐catalyst could reduce e‐ and h+ recombination, improving GdFeO3's photocatalytic performance. The GdFeO3/WS2 possesses a bandgap of 1.9 eV, 178.9 m2 g−1 specific surface area, 0.2 nm pore size, and a lifespan of 6 ns. The optimal GdFeO3/WS2 photocatalyst exhibits a maximum removal of 96.2% at a tetracycline concentration of 10 mg/L, a pH of 3, and 40 mg of photocatalyst in an irradiation time of 90 min. Tetracycline has a higher photocatalytic efficiency in visible light (96.2%) than in sunlight (72.6%). Trapping tests revealed that the major reactive species for tetracycline removal in an aqueous solution are •OH, and •O2‐. The recycle experiment shows no deactivation of the GdFeO3/WS2 photocatalyst after 5 recycles. This study sheds light on the rational design of the GdFeO3/WS2 photocatalyst as a potential material for treating wastewater.

Photo-Fenton-like degradation of tetracycline through peroxymonosulfate activation over 2D BiOBr/FeOOH nanosheets and membrane application

The selection of photosensitizer substrates with high photocatalytic efficiency is crucial for leveraging the advantages of metal-based materials in photo-Fenton-like process. Herein, we report a novel 2D layered BiOBr/FeOOH nanosheets equipped with a built-in electric field (BIEF) to activate peroxymonosulfate (PMS) for the degradation of tetracycline (TC). The photocatalytic efficiency of BiOBr is enhanced by fine-tuning the Br source quantity. Both experimental and theoretical analyses confirm that BIEF at the BiOBr/FeOOH heterointerface expedites the movement of photogenerated electrons, significantly boosting both photocatalytic and photo-Fenton-like activities. The BiOBr/FeOOH + PMS + Vis system exhibits a high TC removal rate of 96 % with only 0.24 mM of PMS and nearly 100 % of PMS utilization. Moreover, affixing BiOBr/FeOOH nanosheets onto a PVDF microfiltration membrane, we establish a continuous flow reactor system for antibiotic wastewater treatment. This system demonstrates a remarkable TC removal efficiency consistently above 97.5 % for 6 h of continuous injection, underscoring its practicality and potential for real-world applications.

Construction of TiO2@Cu2O-CuS heterostructures integrating RGO for enhanced full-spectrum photocatalytic degradation of organic pollutants

This study presents the development and optimization of TiO2@Cu2O-CuS heterostructures, enhanced with reduced graphene oxide (RGO), for efficient photocatalytic degradation of organic pollutants, focusing on imidacloprid. Two configurations, TiO2/RGO/Cu2O-CuS and Cu2O-CuS/RGO/TiO2, are explored to highlight the impact of material layering on photocatalytic efficiency. The strategic integration of RGO optimizes charge transfer, crucial for photocatalysis. Comprehensive characterization techniques, such as X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy, and Nitrogen adsorption-desorption isotherms, provide insights into the crystalline structure, morphology, surface chemistry, and textural properties of the heterostructures. The TiO2/RGO/Cu2O-CuS configuration significantly outperforms its counterpart in photocatalytic activity under full-spectrum (UV–VIS–IR) illumination, due to improved charge carrier dynamics and synergistic interactions between the composite materials. Remarkably, the TiO2/RGO/Cu2O-CuS assembly achieved over 95 % degradation of imidacloprid under simulated solar irradiation, marking a breakthrough in solar spectrum utilization for photocatalysis and exhibits promising recyclability, maintaining its high photocatalytic efficiency even after multiple degradation cycles, highlighting its potential for sustainable pollutant removal applications. Additionally, this configuration demonstrates a twofold increase in degradation efficiency compared to separate UV and VIS irradiations, emphasizing its rapid pollutant removal capability. This research underscores the critical role of material layer sequencing in developing high-efficiency photocatalytic systems and marks a significant advancement in environmental remediation technologies that harness renewable energy sources.

Controlled preparation of bamboo charcoal/BiOCl with efficient visible-light-driven photocatalytic activity for organic pollutant degradation using the residues of bamboo processing

In this research, bamboo charcoal (BC)/BiOCl composites were successfully prepared by a simple hydrothermal method, where the BC was derived from the residues of bamboo processing. The BC/BiOCl composites displayed nanosheet structures with tight combination between bamboo charcoal and BiOCl. The oxygen vacancies (OVs) concentration and photoelectric properties of BC/BiOCl composites were boosted with the doped bamboo charcoal. The photocatalytic performance of the composites was evaluated by the degradation of RhB and TCH. Meanwhile, the possible intermediates, degradation pathways and toxicity of the pollutants in the photocatalytic process were elucidated. When the additive dosage of BC and hydrothermal temperature were 5% and 140°C, the 5BC-140 has highest photocatalytic efficiency under visible light irradiation, and the degradation rates of RhB and TCH over the 5BC-140 composite were 97.9% and 69% at 36 min and 120 min, with the kinetic constants of 6.2 times and 2.0 times as high as those of pure BiOCl, respectively. The establishment of Bi-O-C bonds in the BC/BiOCl played a pivotal role in constructing atomic-level interfacial channels to boost the charge carriers’ separation. The enhanced photocatalytic activity was originated from the robust interaction between bamboo charcoal and BiOCl, promoting the rapid transfer of electrons and suppressing the combination of photogenerated electron-hole pairs through the increased oxygen vacancies. In addition, incubation experiments on green beans demonstrated the nontoxicity of contaminant solution degraded by the BC/BiOCl composites.

Metasurface-enhanced photochemical activity in visible light absorbing semiconductors.

Heterogeneous photocatalysis is an important research problem relevant to a variety of sustainable energy technologies. However, obtaining high photocatalytic efficiency from visible light absorbing semiconductors is challenging due to a combination of weak absorption, transport losses, and low activity. Aspects of this problem have been addressed by multilayer approaches, which provide a general scheme for engineering surface reactivity and stability independent of electronic considerations. However, an analogous broad framework for optimizing light-matter interactions has not yet been demonstrated. Here, we establish a photonic approach using semiconductor metasurfaces that is highly effective in enhancing the photocatalytic activity of GaAs, a high-performance semiconductor with a near-infrared bandgap. Our engineered pillar arrays with heights of ∼150nm exhibit Mie resonances near 700nm that result in near-unity absorption and exhibit a field profile that maximizes charge carrier generation near the solid-liquid interface, enabling short transport distances. Our hybrid metasurface photoanodes facilitate oxygen evolution and exhibit enhanced incident photon-to-current efficiencies that are ∼22× larger than a corresponding thin film for resonant excitation and 3× larger for white light illumination. Key to these improvements is the preferential generation of photogenerated carriers near the semiconductor interface that results from the field enhancement profile of magnetic dipolar-type modes.

The Solvent Role for the Decomposition of Paracetamol in Distilled and Drinking Water by Pure and Ag-Modified TiO2 Sol-Gel Powders.

In this study, pure TiO2 gels were synthesized by applying the sol-gel method, using Ti(IV) butoxide with the addition of two different solvents, namely ethylene glycol (EG) and isopropanol (isop), with only air moisture present. It was established using XRD that the gel prepared with the addition of EG was amorphous even at 400 °C, while the other gel was amorphous up to 300 °C. It was found that TiO2 (anatase) had a dominant crystalline phase during heating to 600 °C, while at 700 °C, TiO2 (rutile) appeared. The as-obtained powdered materials were annealed at 500 °C and subsequently underwent photocatalytic tests with paracetamol. Additionally, the TiO2 samples were modified with Ag+ co-catalysts (10-2 M), using photofixation by UV illumination. The photocatalytic activity of the Ag-modified powders was also tested in the photodegradation of a commonly used paracetamol in aqueous solution under UV light illumination. The obtained data exhibited that the annealed samples had better photocatalytic efficiency and decomposed paracetamol faster in comparison to the non-annealed sol-gel powders. The highest degradation efficiency was observed for the TBT/isop/Ag material, with degradation efficiencies average values of 65.59% and 75.61% paracetamol achieved after the third cycle of photocatalytic treatment. The co-catalytically modified powders had higher photocatalytic efficiency in comparison to the pure nanosized powders. Moreover, the sol-gel powders of TBT/EG, TBT/EG/Ag (10-2 M), TBT/isop, and TBT/isop/Ag (10-2 M) demonstrated the ability to retain their photocatalytic activity even after three cycles of use, suggesting that they could find practical use in the treatment of pharmaceutical wastewater. The observed photocatalytic efficiency and positive impact of silver make the prepared powders a desirable choice for pharmaceutical drug degradation, helping to promote environmentally friendly and effective wastewater treatment technology.

Rare-Earth Metal-Organic Framework with Nonplanar Porphyrin Groups for High-Efficiency Photocatalysis.

Nonplanar porphyrins play crucial roles in many biological processes and chemical reactions as catalysts. However, the preparation of artificial nonplanar porphyrins suffers from complicated organic syntheses. Herein, we present a new rare-earth porphyrinic metal-organic framework (RE-PMOF), BUT-233, which is a three-dimensional (3D) framework structure with the flu topology consisting of 4-connected BBCPPP-Ph ligands H4BBCPPP-Ph = 5',5⁗-(10,20-diphenylporphyrin-5,15-diyl)bis([1,1':3',1″-terphenyl]-4,4'' dicarboxylic acid) and 8-connected Eu6 clusters. Noteworthily, the porphyrin cores of the BBCPPP-Ph ligands in BUT-233 are nonplanar with a ruffle-like conformation. In contrast, the porphyrin core in the free ligand H4BBCPPP-Ph is in a nearly ideally planar conformation, as confirmed by its single-crystal structure. BUT-233 is microporous with 6-8 Å pores and a Brunauer-Emmett-Teller (BET) surface area of 649 m2/g, as well as high stability in common solvents. The MOF was used as a photocatalyst for the oxidation degradation of a chemical warfare agent model molecule CEES (CEES = 2-chloroethyl ethyl sulfide) under the light-emitting diode (LED) irradiation and an O2 atmosphere at room temperature. CEES was almost completely converted into its nontoxic light-oxidized product CEESO (CEESO = 2-chloroethyl ethyl sulfoxide) in only 5 min with t1/2 = 2 min (t1/2: half-life). Moreover, the toxic deep-oxidized product 2-chloroethyl ethyl sulfone (CEESO2) was not detected. The catalytic activity of BUT-233 was high in comparison with those of some previously reported MOF catalysts. The results of photo/electrochemical property studies suggested that the high catalytic activity of BUT-233 was benefited from the presence of nonplanar porphyrin rings on its pore surface.

Photocatalysis and irradiative TL defect center analysis studies of Cu2+ ionic ZnO nano lattice

The objective of the study is to create a series of ZnO nano powders doped with CuO using sol–gel technology in order to look into their photocatalytic activity for the photodegradation and cleaning process. XRD, BET surface area, surface morphology, chemical analysis, and FT-IR measurements have all been used to look at the nano powders' structure from this point of view. The results suggest that the materials were made at the nanoscale level, and their hexagonal shape makes them good as catalytic nano resources. Photoluminescence and UV–visible diffusion reflection spectroscopy were also used to test the nano powders. The results show that the nano powders that were made are visually active. To find out how photocatalytic the nanoparticles are, they were used to break down CR (10 ppm) and MV (10 ppm) dyes when exposed to light. The nano powder with 1.0 mol% of CuO doped ZnO nanoparticles had the highest photocatalytic efficiency (86 %). It had a band gap energy of 3.15 eV and reacted with both dyes for 90 min. Researchers looked at radical scavengers and the effect of catalyst dose on how well they broke down substances. The reaction that broke down had pseudo-first-order kinetics, and the rate of the reaction was four times faster when 1.0 mol% Cu was added to the ZnO catalyst. The degradation efficiency only dropped by 1 % after three rounds of the process. Because of this, the 1.0 mol% Cu-ZnO was used as a photocatalyst that broke down textile dyes well and had a lot of promise to be used again. The samples were also checked for thermoluminescence while they were exposed to 25 kGy of gamma radiation. Samples were tested for their trap depth characteristics, indicating the test samples' potential for TL activity.

Enhanced Fenton-like process over Z-scheme MoO3 surface decorated with Fe2O3 under visible light

Photocatalysts consisting of Z-scheme heterojunctions are commonly used in wastewater treatment due to their exceptional reactivity in photocatalysis and highly efficient visible-light utilization. In this work, Fe2O3-decorated MoO3 rods were synthesized through a two-step method and their photodegradation of methylene blue (MB) was evaluated. The Fe2O3/MoO3 rods were characterized by XRD, SEM, micro-Raman, XPS, UV–Vis DRS, and PL to investigate their structural, morphological, and optical properties. The results indicate that the photodegradation efficiency of Fe2O3/MoO3 improved through a reduction in the gap energy and persistence of a 1D hexagonal prism structure. The degradation rate of MB was enhanced from 31.7 to 91.5% after irradiation for 180 min owing to electron–hole separation and Fenton-like process. Formation of the OH radical is a key factor in the photodegradation reaction and with the addition of H2O2 the efficiency can further improve via a Fenton-like mechanism. Furthermore, the Z-scheme mechanism concurrently delineated. The Fe2O3/MoO3 rod composites were also found to retain high photocatalytic efficiency after being reused five times, which may be useful for future applications.

CTAC-assisted monoclinic BiVO4 with oxygen defects for efficient photocatalytic performances: A combined experimental and DFT study

Developing a photocatalyst with high photocatalytic efficiency, chemical stability, and self-degradation capability is essential for optimizing photodegradation processes in environmental applications. In this study, we synthesized a monoclinic BiVO4 photocatalyst whose surface morphology was modulated by hexadecyltrimethylammonium chloride (CTAC) using a facile hydrothermal method. Experimental results demonstrated a substantial increase in the degradation rate (99%) for the CTAC-modified monoclinic BV/CT25 photocatalyst (with an initial CTAC concentration of 25 g/L) compared to the CTAC-free tetragonal BiVO4 photocatalyst (73%). This highlights the effective enhancement of photocatalytic degradation performance through CTAC modification. Furthermore, density functional theory (DFT) calculations revealed that the band gap of BV/CT25 remained unchanged, suggesting that changes in oxygen vacancies (OVs) and density of states, along with the porous lattice structure, contributed to the improved performance. These findings were further supported by FESEM, as well as EPR and XPS characterizations. In addition, photodegradation tests at various pH conditions and cyclic tests suggested that the modification enhanced the morphological stability and reusability of the modified BiVO4 photocatalysts. Overall, this study provides valuable insights into the design of next-generation photocatalysts, leveraging surfactants to control surface properties and emphasizing the key attributes of high photocatalytic efficiency, chemical stability, and improved reusability.

Sunlight driven photocatalytic degradation of organic pollutants by solvothermally synthesized rGO-BiVO4 nanohybrids

This study reports photocatalytic degradation of organic dyes by rGO-BiVO4 nanohybrids. rGO- BiVO4 nanohybrids were solvothermally prepared with different rGO loading (1.5, 3 and 6 %) and their structural, optical and photocatalytic properties were investigated. Effect of rGO loading on photocatalytic dye degradation was studied and the factors responsible were analyzed. Structural analysis was done using XRD and Raman analyses which clearly showed monoclinic phase of the BiVO4. FESEM images showed sub-micron spheres of BiVO4 along with sheet-like structures corresponding to rGO. A slight change in the band gap was observed from 2.2 eV for BiVO4 to around 2 eV for the rGO-BiVO4 nanohybrids. Band to band transitions as well as the transitions from the defect bands were observed from the PL spectra. Photocatalytic degradation studies of organic pollutant MB under natural sunlight showed 3 % rGO-BiVO4 to be the best photocatalyst which degraded 88.4 % of MB in 80 min with rate constant of 0.0244 min−1. It was observed that for obtaining a maximum catalytic efficiency an optimum loading of rGO proved to be best. In either case of higher or lower loading of rGO showed a lower degradation performance. Amongst the samples synthesized 3 % rGO loading was found to be the optimum rGO loading to have the lowest band gap (2 eV) as well as the reduced recombination that has resulted in highest photocatalytic efficiency under solar irradiation.