Durable Photocatalyst Research Articles

Bismuth-Metal and Carbon Quantum Dot Co-Doped NiAl-LDH Heterojunctions for Promoting the Photothermal Catalytic Reduction of CO2.

The quest for sustainable photocatalytic CO2 reduction reactions (CRR) emphasizes the development of high-efficiency, economically viable, and durable photocatalysts. A novel approach involving the synthesis of Bi-CDs/LDH heterojunctions, incorporating plasma metals and carbon quantum dots via hydrothermal and co-precipitation methods, yields remarkable results. The optimized BCL-4 photocatalyst demonstrates exceptional performance, with C2H4 and C2H6 yields of 1.35 and 2.17µmolg-1h-1, respectively, representing substantial enhancements of 11.25 and 14.47 times compared to the LDH monomer. Moreover, the catalyst exhibits a notable selectivity of 36.6% for C2 products. Plasmonic Bi with high conductivity and carbon quantum dots synergistically enhances visible light absorption and generated additional hot electrons. The electron-trapping ability of carbon quantum dots is pivotal in creating elevated electron and CO2 concentrations at the catalyst interface, fostering conditions conducive to promoting C─C coupling reactions for the generation of C2 products.

Noble‐Metal‐Free Modified TiO2 Nanotube Arrays (TNTAs) for Efficient Photocatalytic Reduction of CO2 to CO Under Visible Light

AbstractIn the past decades, TiO2 nanotube arrays (TNTAs) have gained a great attention as a durable photocatalyst for CO2 reduction due to their unique properties. TNTAs have been widely modified with noble metals for increasing their absorption of visible light and limiting their associated rapid electron‐hole recombination rate. However, these metals are extremely expensive, which limits their practical applications in the fields of energy and environment. In this study, three noble‐metal‐free materials of graphitic carbon nitrides, metal–organic framework, and reduced graphene oxide were used for modifying pure TNTAs through a simple drying‐deposition method. The modified TNTAs samples were characterized by X‐ray diffraction, Fourier transform infrared, field emission scanning electron microscopy and energy‐dispersive X‐ray spectroscopy analyses for approving successful synthesis of these nanocomposites. Finally, the modified TNTAs nanocomposites were investigated for their ability in converting the CO2 gas to CO under visible light. However, the TNTAs modified with graphitic carbon nitrides displayed the highest CO productions of 27551 µmol m−2 which represents 16% enhancement compared to that of pure TNTAs (23871 µmol m−2). The enhanced CO2 photoreduction performance of modified TNTAs is attributed to promoted light absorption, increased surface area, and improved electrical conductivity.

La3+-Schiff base complex for the degradation of Rhodamine B: Kinetic studies and reactive species identification

The research investigates the characteristics of the La-H2L complex through molar conductivity experiments, XPS, SEM, EDX, BET and UV-visible spectroscopy, revealing a band gap of 2.76 eV. Its photocatalytic efficacy was tested for the degradation of Rhodamine B (RhB) dye under UV light. Optimization studies determined the optimal conditions for pH, initial dye concentration, and catalyst dosage, leading to a 72.2 % reduction in RhB concentration. Kinetic analysis demonstrated that the degradation followed pseudo-first-order kinetics with a rate constant of 0.0169 min⁻¹. Scavenger studies identified hydroxyl radicals, holes, and superoxide radicals as the primary reactive species involved. High-Resolution Mass Spectrometry (HRMS) identified intermediate products and provided insights into the degradation pathways. The La-H2L complex exhibited remarkable stability and reusability, retaining 85 % of its photocatalytic activity after five cycles. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) confirmed the structural integrity and stability of the complex post-degradation. These results underscore the La-H2L complex's potential as a highly effective and durable photocatalyst for environmental remediation.

Reinforced BiOBr for visible-light-driven nitrogen fixation: A synergistic effect of cocatalyst and oxygen vacancies

Photocatalytic nitrogen fixation is a promising long-term strategy for NH3 synthesis, with the development of effective and durable photocatalysts being crucial for achieving high-efficiency N2 to NH3 conversion. In this study, we employed vacancy and interface engineering to create bismuth (Bi) nanoparticles on hierarchical oxygen-deficient BiOBr microspheres using a one-step solvothermal approach. These Bi-decorated BiOBr microspheres, featuring oxygen vacancies, achieved a high photocatalytic ammonia synthesis rate of 222.3 μmol·g−1·h−1 in pure water under visible light irradiation, which is 3.25 times higher than that of the original BiOBr. Atomic-scale images of the interface between the defective regions of BiOBr and the Bi cocatalyst and several other material characterizations confirmed that the enhanced photoreduction activity of Bi/BiOBr is due to the synergistic effects of the metal Bi and the oxygen vacancies. These results present a straightforward and practical method for designing efficient photocatalysts for nitrogen fixation.

A New Class of Multifunctional CoDyzFe2−zO4 Magnetic Nanomaterials: Influence of Structural, Morphological, Optical, Magnetic, Antibacterial, and Photocatalytic Traits

Here we focus on preparing recoverable Dy doped CoFe2O4 photocatalysts for the removal of the malachite green pollutant (MGP) in natural Sunlight. XRD results demonstrate development of the spinel symmetry with no impurities phases. The FESEM analysis revealed spherical grains with definite grain boundaries and agglomerated behavior. We found that our synthesized photocatalysts behaves as an excellent magnetic nanomaterial by observing the saturation magnetization of 77.79 emu g−1. Out of all photocatalysts, CoDy0.03Fe1.97O4 nanophotocatalyst exhibit the high zone of inhibition (ZOI) for Staphylococcus aureus and Escherichia coli. It makes the prepared nanomaterials highly suitable for the biological purposes. The effectiveness of photocatalytic degradation activity of prepared specimens is significantly impacted by the addition of dysprosium ions. During a 150 min of reaction period, CoDy0.03Fe1.97O4 has a higher degradation percentage around 95.36% as compared to CoFe2O4 (86.09%). The prepared doped and undoped CoFe2O4 nanomaterials displayed the least decline in the degradation percentage of MGP after four reuse cycles and this might be attributable to the weight loss during the recovery. Therefore, the nanomaterials suggested a reliable and durable photocatalyst for degradation process. Hence the prepared magnetically recoverable and multifunctional photocatalysts are reliable for the water remediation and biological usages.

Phase transition influenced photocatalytic dye degradation capability of pure and Eu-doped CoMoO4 polymorphic nanostructures

ABSTRACT The efficient degradation of organic dyes via photocatalysis presents a critical environmental challenge, necessitating advancements in catalyst design and performance. This study investigates the potential of pure and Eu doped CoMoO4 polymorphic nanostructures in addressing this challenge. Our primary focus is on enhancing the efficiency and stability of photocatalysts under diverse condition by performing sol–gel synthesis. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV-visible) analysis and Raman analysis was employed to elucidate structural and morphological changes. Our results highlight the significant enhancement in photocatalytic activity achieved through phase transitions induced by Eu doping. This enhancement is attributed to the creation defect sites and the establishment of improved charge transfer pathways within the CoMoO4 nanostructures. By shedding light on the role of phase transition in photocatalysis, this study contributes valuable insights for the design of efficient and durable photocatalysts for environmental remediation application.

Synergistic enhancement of photocatalytic efficiency and durability in CoNi-decorated Cu2O/Cu films for superior synthetic dye degradation

The Cu2O/Cu emerges as a promising candidate for photocatalytic application owing to its efficient photon absorption in the visible light spectrum. However, the susceptibility of Cu2O-based photocatalysts to self-decomposition diminishes their effectiveness. This study introduces CoNi as co-catalyst to enhance the durability of Cu2O/Cu photocatalyst. Electrodeposition was employed to decorate the Cu2O/Cu crystal surface with Co, Ni and CoNi. The deposition potential of CoNi was optimized to produce a high-performance photocatalyst. The utilization of CoNi co-catalyst resulted in significant enhancements in photoelectrochemical properties under light irradiation when compared to using a single Co or Ni co-catalyst, suggesting a synergistic effect between Co and Ni within the system. The enhancement is evidenced by a noteworthy increase in the photocurrent of the photocatalyst, rising from 10.24 mA/cm2 to 20.81 mA/cm2. In addition, the decoration of CoNi resulted in a reduction of the charge transfer resistance from 4.2 kΩ to 0.7 kΩ, while simultaneously increasing the electrochemically active surface area of the photocatalyst from 15.49 cm2 to 157.69 cm2. The observed modifications lead to a substantial improvement in the photocatalytic efficiency, resulting in an impressive 88 % degradation of methylene blue, which is 3.4 times higher than achieved in the absence of the co-catalyst. Moreover, there was a significant improvement in the photostability of the photocatalyst, with an increase from 16.81 % to 50.55 %. These findings demonstrate the significance of CoNi co-catalyst decoration in producing a highly active and durable photocatalyst, making it a promising candidate for efficient synthetic dyes degradation.

Preparation of La-doped ZnFe LDH immobilized on polydimethylsiloxane sponge for the peroxymonosulfate-assisted photocatalytic degradation of rifampicin

In this study, La-doped ZnFe layered double hydroxide (La-ZnFe LDH) was immobilized on polydimethylsiloxane (PDMS) sponges and applied in the photocatalytic degradation process for the activation of peroxymonosulfate (PMS). The La-ZnFe LDH, PDMS sponge, and PDMS@La-ZnFe LDH samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FT-IR) analyses, and contact angle goniometer. The immobilized catalyst had a porous structure with a specific surface area of 5.94 m2 g−1 and a pore volume of 1.36 cm3 g−1. The PDMS@La-ZnFe LDH has the high potential to degrade rifampicin by activating PMS with a notable synergistic factor of 3.38. The optimum operating conditions for the degradation of 15 mg L−1 of rifampicin were determined as 0.2 mmol L−1 of PMS, 100 W of light intensity, and pH of 8, conducting the degradation efficiency to 92.8% within 360 min. According to the radical quenching tests, h+, •OH, SO4•−, and O2•− exhibited an important role in the rifampicin degradation. Besides, the PDMS@La-ZnFe LDH sponge possessed excellent reusability during the PMS-activated photocatalytic process after seven consecutive runs. Furthermore, the treatment of rifampicin from real wastewater was also evaluated. GC-MS analysis was carried out to determine the generated by-products during the photocatalytic degradation process. Briefly, La-ZnFe LDH catalyst immobilized with PDMS sponges can be a promising reusable and durable photocatalyst for the degradation of refractory organic pollutants.

Phosphorylated g-C3N4/sulfur self-doped g-C3N4 homojunction carboxymethyl cellulose beads: An efficient photocatalyst for H2O2 production

The development of highly reusable, affordable, and durable photocatalysts for the production of hydrogen peroxide (H2O2) remained a challenge. In this study, a homojunction photocatalyst (SPGCN) is constructed between phosphorylated g-C3N4 (PCN) and sulfur self-doped g-C3N4 (SCN) using a simple wet impregnation method. Later, the obtained SPGCN homojunction is transformed into hydrogel beads using carboxymethyl cellulose via an effective cross-linking strategy (SPGCN/CMC). The photocatalytic beads displayed a phenomenal H2O2 production of 3.5 mM under visible light illumination for 60 min. The SPGCN/CMC hydrogel beads showed a maximum reusability of 10 cycles with a decline of 1.5 mM H2O2 production. The improved photocatalytic efficiency is indicated by strengthened utilization of visible light via tuning of the band gap, suppressed recombination of electron-hole pairs, and higher separation efficiency through the effective construction of Z-scheme between the phosphorylated carbon nitride and the sulfur-self-doped carbon nitride present in the SPGCN/CMC beads. The mechanistic studies affirmed the dominant role of superoxide radicals in H2O2 production. The photocatalytic H2O2 production followed a highly selective two-electron reduction reaction. Overall, this study highlights the efficient engineering of carbon nitride-based materials towards artificial photosynthesis.

Ultrasonic synthesis of Graphite/C, N co-doped TiO2 nanocomposite as an efficient and durable photocatalyst for the degradation and mineralization of p-nitrophenol

P-nitrophenol (PNP) as an industrial waste effluent is present in many industries, including the dye and textile industries and tanneries, and is the cause of severe human and environmental health risks. In the present study, a facile, effective, and innovative sonochemical procedure was developed at low frequency (20 kHz) and room temperature for the synthesis of graphite (G)/C, N co-doped TiO2 nanocomposite. Herein, tetra n-butyl orthotitanate as the titanium precursor, graphite as the C, and NH4Cl as the N sources were applied in the synthesis of the nano-photocatalyst. The effect of the molar ratio of N/TiO2 was studied in the synthesis of G/C, N co-doped TiO2 nanocomposite. Various techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), High-resolution microscopy (HRTEM), X-ray Photoelectron Spectroscopy (XPS), photoluminescence (PL), Brunauer–Emmett–Teller (BET), Elemental and Mapping analyses (EDS) and UV/Vis diffuse reflectance (UV/vis DRS) were used to characterize the nanocomposite. The results also showed that ultrasound decreased the particle size and improved the size distribution. DRS results showed a narrower band-gap and a red shift of light absorption edge for G/C, N co-doped TiO2 nanocomposite compared to TiO2. The data obtained from XPS established the presence of C, N, Ti, and O elements in the nanocomposite. In addition, the efficiency of the photo-catalytic performance of the nanocomposite was assessed using the pollutant PNP. The fabricated nanocomposite presented photo-catalytic activity much more than TiO2 in PNP degradation with an efficiency of 100 % within 70 min under the illumination of 400 W Xe light. The extraordinary activity of nanocomposite concerning TiO2 was mostly attributed to its high crystallinity, strong visible light absorption, and the impressive separation of photo-induced charge carriers. The radicals in the charge of destruction process were checked via the scavenging tests. The results confirmed that °O2− radical had a basic role in the process of photo-catalytic and an acceptable mechanism was proposed for the photo-catalytic degradation.

Construction of 1D/3D Co9S8/Mn0.3Cd0.7S Schottky heterojunction for dramatically boosted photocatalytic H2 evolution performance

One of the most crucial strategies for transforming solar energy into sustainable hydrogen energy is photocatalytic H2 evolution, and constructing an effective and durable photocatalyst remains a difficult task. Herein, a 1D/3D Co9S8/Mn0.3Cd0.7S Schottky heterojunctions were successfully fabricated by three-step hydrothermal procedure, in which 3D Mn0.3Cd0.7S solid solution particles were immobilized on the 1D tube-like Co9S8 surface, allowing for extremely effective charge separation and transfer. Through coupling Co9S8 with Mn0.3Cd0.7S, the photocatalytic H2 evolution activity and stability were significantly boosted. The 7 % Co9S8/Mn0.3Cd0.7S heterojunction possessed the highest photocatalytic activity with the H2 evolution rate of 1586.4 μmol⋅h−1, which was 3.73 times larger than that of pristine Mn0.3Cd0.7S, corresponding to 21.8 % apparent quantum efficiency (AQE) at 420 nm monochromatic light. The Schottky heterojunction mechanism between Co9S8 and Mn0.3Cd0.7S could plausibly explain the enhanced photocatalytic H2 evolution performance, according to density functional theory (DFT) calculations and ultraviolet photoelectron spectroscopy (UPS) measurements. This investigation would offer the useful insights to develop Co9S8 cocatalyst for application in photocatalytic H2 evolution.

Magnetically separable MnFeCoNiCu-based high entropy alloy nanoparticles for photocatalytic oxidation of antibiotic cocktails in different aqueous matrices

Destroying persistent organic pollutants via photocatalytic advanced oxidation processes is critical for sustainable water management. In spite of the tremendous progress in developing highly effective and durable photocatalysts in recent decades, inferior optical absorption and rapid charge recombination considerably restrict their application on a commercial scale. In order to address these issues, herein we have constructed MnFeCoNiCu-based high entropy alloy (HEA) nanoparticles (NPs), through a facile and straightforward procedure, and showcase its superiority over conventional photocatalysts in degrading some typical antibiotics (viz., sulfamethoxazole, SMX; ofloxacin, OFX; and ciprofloxacin, CFX). The equimolar HEA-NPs feature n-type semiconducting properties, improved light trapping ability, and reduced charge recombination. Consequently, a high degradation of 95 %, 94 %, and 89 % for SMX, OFX, and CFX, respectively, can be achieved in the presence of MnFeCoNiCu NPs under visible light illumination, without any serious risks of secondary contamination. In order to better evaluate the photocatalytic performance of MnFeCoNiCu NPs, particularly from a practical perspective, the removal of antibiotic pollutants from multicomponent systems is also investigated. The average treatment efficiency for a ternary mixture of SMX, OFX, and CFX in different aqueous matrices decreases in the order of deionized water (∼82 %) < tap water (∼86 %) < river water (∼78 %) < hospital wastewater (∼60 %) < domestic wastewater (∼57 %) < pharmaceutical industry wastewater (∼47 %). Further, the expended HEA-NPs can be conveniently recovered from the reaction system by applying an external magnetic field, allowing recurrent usage, without any substantial alteration in their microstructure and performance. These demonstrations of satisfactory photocatalytic activity under a diverse spread of realistic environmental conditions, excellent durability, and inexpensive retrieval endorse the application potential of MnFeCoNiCu NPs in decentralized water treatment systems.

Sacrificial-agent-free artificial photosynthesis of hydrogen peroxide over step-scheme WO3/NiS hybrid nanofibers

Developing low-cost and durable photocatalysts for sacrificial-agent-free artificial photosynthesis of hydrogen peroxide is challenging. In this work, an all-inorganic hybrid nanofiber step-scheme photocatalyst, WO3/NiS (WONS), was constructed for efficient generation of hydrogen peroxide in pure water at ambient condition. The optimal photocatalyst, WONS35 % (with 35 wt% of NiS), exhibits remarkable efficiency in producing H2O2 at a rate of 2.59 mmol gcatalyst−1 h−1 under visible light illumination, surpassing the H2O2 production rate of pristine WO3 and NiS by 11.3 and 16.7 times, respectively. WONS35 % demonstrates an apparent quantum yield of 4.97 % at a wavelength of 420 nm. The significantly enhanced photocatalytic performance can be ascribed to the synergistic effect of the improved charge separation and transfer induced by the step-scheme pathway and the highly selective two-electron oxygen reduction reaction (ORR) over the hybrid nanofiber photocatalyst.

Boosted Photocatalytic Performance for Antibiotics Removal with Ag/PW12/TiO2 Composite: Degradation Pathways and Toxicity Assessment.

Photocatalyst is the core of photocatalysis and directly determines photocatalytic performance. However, low quantum efficiency and low utilization of solar energy are important technical problems in the application of photocatalysis. In this work, a series of polyoxometalates (POMs) [H3PW12O40] (PW12)-doped titanium dioxide (TiO2) nanofibers modified with various amount of silver (Ag) nanoparticles (NPs) were prepared by utilizing electrospinning/photoreduction strategy, and were labelled as x wt% Ag/PW12/TiO2 (abbr. x% Ag/PT, x = 5, 10, and 15, respectively). The as-prepared materials were characterized with a series of techniques and exhibited remarkable catalytic activities for visible-light degradation tetracycline (TC), enrofloxacin (ENR), and methyl orange (MO). Particularly, the 10% Ag/PT catalyst with a specific surface area of 155.09 m2/g and an average aperture of 4.61 nm possessed the optimal photodegradation performance, with efficiencies reaching 78.19% for TC, 93.65% for ENR, and 99.29% for MO, which were significantly higher than those of PW12-free Ag/TiO2 and PT nanofibers. Additionally, various parameters (the pH of the solution, catalyst usage, and TC concentration) influencing the degradation process were investigated in detail. The optimal conditions are as follows: catalyst usage: 20 mg; TC: 20 mL of 20 ppm; pH = 7. Furthermore, the photodegradation intermediates and pathways were demonstrated by HPLC-MS measurement. We also investigated the toxicity of products generated during TC removal by employing quantitative structure-activity relationship (QSAR) prediction through a toxicity estimation software tool (T.E.S.T. Version 5.1.2.). The mechanism study showed that the doping of PW12 and the modification of Ag NPs on TiO2 broadened the visible-light absorption, accelerating the effective separation of photogenerated carriers, therefore resulting in an enhanced photocatalytic performance. The research provided some new thoughts for exploiting efficient and durable photocatalysts for environmental remediation.

An S-scheme NH2-MIL-101(Fe)@MCN/Bi2O3 heterojunction photocatalyst for the degradation of tetracycline and production of H2O2

Effective and durable photocatalysts are essential for the decomposition of persistent contaminants and the generation of hydrogen peroxide. In this study, we successfully constructed an S-type heterojunction by in situ growing Bi2O3 nanocrystals and NH2-MIL-101(Fe) onto surface-modified g-C3N4. The process of charge transfer in the S-type heterojunction was confirmed using ISI-XPS, DFT calculations, capture experiments, and EPR signals. The combined influence of the heterojunction and MOF demonstrated remarkable photocatalytic performance in the breakdown of tetracycline (TC) and the generation of hydrogen peroxide (H2O2). In the enhanced setup (10%–NH2–MIL-101(Fe)@MCN/Bi2O3), full degradation of TC was accomplished within 50 min under visible light exposure. Additionally, a notable H2O2 yield of 655.63 μmol/g was attained, all achieved without the necessity of sacrificial agents or supplementary oxygen. Based on the outcomes of the dual functionality, the exceptional performance of the ternary composite material can be ascribed to the collaborative influence of the heterojunction and MOF. This collaborative effect expands the light absorption range in the visible region, suppresses the recombination of electron-hole pairs, and enhances the photocatalytic redox ability. The system demonstrates significant potential in the efficient in situ production of H2O2 and removal of recalcitrant organic pollutants in pure water.

Use in Photoredox Catalysis of Stable Donor–Acceptor Covalent Organic Frameworks and Membrane Strategy

AbstractOptoelectronic attributes notwithstanding donor–acceptor covalent organic frameworks (D–A COFs) are not durable photocatalysts in many cases. Herein, a stabilization strategy of D–A COFs by intramolecular hydrogen (H)‐bonds and a membrane‐based mass transfer strategy for photocatalytic modulation are reported. The crystalline stability design of COF is cored at the strong π–π interactions and the H‐bonds of adjacent tetrakis(4‐formylphenyl)pyrene and naphthalenediimide units and the D–A charge transfer is designed for efficiency optimization. The well‐defined, stable structure and charge dynamics of D–A COF, and the structure‐controlled reactive oxygen species yields are confirmed. In two photoredox models, the COF presents both robust activity and stability and is further integrated with the mass transfer optimization of the COFs/polyvinylidene fluoride membrane. The membrane is recycled at least 15 times, and the turnover frequency value of g‐scale amine coupling is as high as 62.4 h−1. This work offers a facile approach to the stabilization design of D–A COFs and explores a general membrane‐based mass transfer strategy for photocatalysis.

Degradation Behavior of Donor‐acceptor Cyanoarenes‐based Organic Photocatalysts

AbstractVisible‐light photocatalysis has emerged as a powerful tool for organic transformations in recent years. The traditional reliance on transition metal‐based complexes as photocatalysts has raised concerns regarding their toxicity and the sustainability of precious metals, leading to the exploration of organic photocatalysts. Organic photocatalysts offer high structural diversity and eliminate the need for metal removal, addressing the aforementioned concerns. Notably, donor−acceptor cyanoarenes, originally developed as thermally activated delayed fluorescence emitters, have gained significant attention due to their unique properties as photocatalysts with high efficiency. Consequently, understanding the stability of these catalysts has become essential for further enhancing their performance. This review provides a comprehensive overview of recent studies focusing on the stability of organic photocatalysts. Key issues such as photodegradation and interactions with active species are discussed, offering insights into the durability of photocatalysts. Furthermore, we aim to present the current status while also identifying important directions for future research.

MIL-101(Fe)/polysulfone hollow microspheres from pickering emulsion template for effective photocatalytic degradation of methylene blue

The utilization of metal-organic frameworks (MOFs) as photocatalysts for the degradation of organic pollutants has gained significant attention in recent years, yet the challenge of recycling MOFs has hindered their widespread use. In this study, we have fabricated a novel MIL-101(Fe)/Polysulfone (MP) composite hollow microsphere via a Pickering emulsion template approach for the application in photo-Fenton degradation of methylene Blue (MB). Our results revealed that the loading of MIL-101(Fe) plays a crucial role in determining the porosity, density, and optical properties of the MP composite microspheres. The MP composite microspheres exhibited excellent MB removal performance and showed a higher adsorption rate compared to MIL-101(Fe) and Polysulfone (PSF). The enhanced performance can be attributed to the porous structure and electrostatic attraction between MB+ and negatively charged PSF materials. Additionally, the MP composite microspheres displayed good degradation efficiency and a high degree of reusability, remaining stable even after 5 cycles. These results demonstrate that the MP composite microsphere is a highly effective, reusable, and durable photocatalyst for the treatment of water and organic pollutants.

Photocatalytic Overall Water Splitting Reaction Feature on Photodeposited NixP/γ-Ga2O3Nanosheets

Solar light-driven overall water splitting for hydrogen production is an ideal solution to climate warming and energy shortage issues. Obtaining a highly efficient and stable photocatalyst remains a major challenge at present. Herein, NixP/γ-Ga2O3 nanosheets, which were synthesized from NiCl2, NaH2PO2, and home-made γ-Ga2O3 nanosheets by the photodeposition method under 254 UV irradiation for 30 min, are found as a highly active and durable photocatalyst for pure water splitting into H2 and O2 without a sacrificial reagent. The H2 production rate is as high as 5.5 mmol·g–1·h–1 under 125 W high-pressure mercury lamp irradiation, which is 3.4 and 2.5 times higher than that on the pristine γ-Ga2O3 nanosheets and Pt/γ-Ga2O3 nanosheets, respectively, and is 2.0 times higher than that on the 0.5 wt % Ni2P/γ-Ga2O3 reported previously. However, the O2 evolution rate is much less than the H2 evolution rate in the initial reaction stage. On prolonging the irradiation time, H2 evolution declines, while O2 evolution increases until it reaches its stoichiometric value corresponding to H2. The reason for the photocatalytic behavior of NixP/γ-Ga2O3 is studied and the corresponding mechanism is suggested. The absent or low oxygen evolution in the initial reaction stage is because the dioxygen generated from water oxidation by the photogenerated holes is wholly or partially captured by the surface oxygen vacancies to form the surface peroxide bonds (−O–O−). Once the oxygen vacancies are eliminated by the photogenerated O2, the overall water splitting reaction would reach the steady state. Thereafter, H2 production decreases from 5.5 to 2.0 mmol·g–1·h–1, but the O2 evolution gradually approaches the corresponding stoichiometric value, especially for the photocatalyst treated with H2O2 for 24 h.

Synthesis and photoelectrochemical catalytic properties of polyoxometalate supported on zeolitic imidazolate Framework, ZIF-9–PMo12

Development of photocatalysts for hydrogen generation is highly imperative in the current scenario for resolving the worldwide energy crisis. Continuous efforts are being made to find low-cost and durable photocatalysts with better light absorption capacity to mitigate energy issues. Herein, a new p-n heterojunction photocatalyst has been synthesized successfully using a polyoxometalate (POM), phosphomolybdic acid (PMo12), and zeolitic imidazolate framework (ZIF-9). Photoelectrochemical studies under visible-light irradiation revealed that ZIF-9–PMo12 exhibits a higher photocurrent density than pure ZIF-9. The support of ZIF-9 prevented the instability of PMo12 in aqueous solutions and improved the photoresponse ability of ZIF-9. The p-n junction formation impedes the recombination of electrons and holes, resulting in the improved photocatalytic property. Photoelectrochemical experiments confirmed the photocatalytic features, and thus this work paves the way for the development of an efficient, stable, and low-cost photocatalyst for green H2 generation.