Exceptional Photocatalytic Activity Research Articles

Highly efficient CO2 photoreduction by ultralow-Ru-Loading ZIF-67

Developing highly efficient and low-cost photocatalysts for CO2 reduction is of critical importance for the conversion of CO2 to value-added chemicals. Here we report a Co-based zeolitic imidazole framework (ZIF-67) based photocatalyst with exceptional photocatalytic activity and durability for CO2 reduction. ZIF-67 is doped with dicyandiamide (DCD), the intermediate link with the trace Ru cocatalyst (0.0127 wt. %). The underlying reduction mechanism was unraveled by the joint experiment-theory study. The strong orbital coupling of ZIF-67-DCD-Ru series structure leads to strong CO2 adsorption, electron enrichment on cocatalyst, and minimum Gibbs free energy barrier of CO generation. The synthesized ZIF-67/DCD/Ru sample exhibits excellent CO2 photoreduction performance with a CO generation rate of 1495 mmol gRu−1 h−1 and achieves a record turnover frequency (TOF) of 151 h−1, representing top-level photocatalytic activity among all reported ZIFs-based photocatalysts. For the first time, our work points out a novel way to achieve high activity of ultralow noble metal loading photocatalyst and provides an in-depth understanding of the advances of the series structure.

Ultrathin 2D type-II heterojunctions ZCLDH/CN with a higher photocatalytic performance of ciprofloxacin under simulated light illumination

Novel incorporation of graphitic carbon nitride on zinc cobalt-layered double hydroxide (ZCLDH/CN-10) via a single-step hydrothermal treatment was carried out for photocatalytic activity. The fabrication of ZCLDH/CN-10 binary photocatalysts by in-suit growing ZCLDH on the surface of CN may improve the absorption range and separation of photogenerated carriers. The inclusion of ZCLDH and CN increases the charge separation of photo-generated and wide surface area, resulting in exceptional photocatalytic activity of ciprofloxacin (CIP) degradation. As a result, under visible light the ZCLDH/CN-10 shows a better catalytic degradation efficiency of 98.3% within 120 min. Moreover, the ZCLDH/CN-10 has outstanding stability, with 90% efficiency retention after five consecutive cycles. The trapping tests show that hydroxide radicals (OH) and holes (h+) were the most important in the degrading processes.

Cost-Effective and Highly Efficient Manganese-Doped MoS2 Nanosheets as Visible-Light-Driven Photocatalysts for Wastewater Treatment.

One of the main objectives in wastewater treatment and sustainable energy production is to find photocatalysts that are favorably efficient and cost-effective. Transition-metal dichalcogenides (TMDs) are promising photocatalytic materials; out of all, MoS2 is extensively studied as a cocatalyst in the TMD library due to its exceptional photocatalytic activity for the degradation of organic dyes due to its distinctive morphology, adequate optical absorption, and rich active sites. However, sulfur ions on the active edges facilitate the catalytic activity of MoS2. On the basal planes, sulfur ions are catalytically inactive. Injecting metal atoms into the MoS2 lattice is a handy approach for triggering the surface of the basal planes and enriching catalytically active sites. Effective band gap engineering, sulfur edges, and improved optical absorption of Mn-doped MoS2 nanostructures are promising for improving their charge separation and photostimulated dye degradation activity. The percentage of dye degradation of MB under visible-light irradiations was found to be 89.87 and 100% for pristine and 20% Mn-doped MoS2 in 150 and 90 min, respectively. However, the degradation of MB dye was increased when the doping concentration in MoS2 increased from 5 to 20%. The kinetic study showed that the first-order kinetic model described the photodegradation mechanism well. After four cycles, the 20% Mn-doped MoS2 catalysts maintained comparable catalytic efficacy, indicating its excellent stability. The results demonstrated that the Mn-doped MoS2 nanostructures exhibit exceptional visible-light-driven photocatalytic activity and could perform well as a catalyst for industrial wastewater treatment.

One-pot synthesis of octahedral NiSe2 as a co-catalyst for enhanced CO2 photoreduction performance

Excessive CO2 concentrations in the atmosphere have a range of adverse effects, including climate change and the rise in sea levels. One approach to mitigate these issues is to utilize artificial photosynthesis, which transforms CO2 into valuable fuels. In this study, a unique octahedral nickel selenide (NiSe2) structure supported on one-dimensional (1D) nickel titanate nanofibers (NiTiO3 NFs) was created through a one-pot solvothermal process. The optimized NiTiO3 NFs/NiSe2 nanostructure exhibits exceptional CO2 photoreduction performance across a broader range of the solar spectrum (UV–vis). At a 0.09 wt% NiSe2 concentration, the yields of CH4 and CO were 3.14 and 1.47 times higher, respectively, than those produced by pure NiTiO3 NFs. The exceptional photocatalytic activity can be attributed to the efficient electron extraction and transfer from NiTiO3 NFs to NiSe2, as well as the enhanced light harvesting capacity. Furthermore, the introduction of NiSe2 generates more oxygen vacancies (OV) that can promote the adsorption and activation of CO2 and water, considerably reducing the free energy barrier for COOH* formation and accelerating the reaction kinetics. The results of this study are expected to create new opportunities for synthesizing efficient photocatalysts based on transition metal dichalcogenides that can be utilized in energy conversion applications.

Novel g-C3N4/BiVO4 heterostructured nanohybrids for high efficiency photocatalytic degradation of toxic chemical pollutants

Novel heterostructured hybrid catalysts are essential for the efficient photocatalytic removal of organic pollutants from wastewater generated by the pharmaceutical and textile industries. In this study, novel g-C3N4/BiVO4 nanohybrid catalysts were prepared using a solvothermal technique, and examined their structural and optical properties using different characterizations. The X-ray diffraction analysis confirmed the monoclinic crystal phase of BiVO4. Field emission scanning electron microscopy (FESEM) images revealed that g-C3N4 sheets anchored on the surface of BiVO4 nanospheres. X-ray photoelectron spectroscopy (XPS) analysis confirmed the oxidation states of g-C3N4/BiVO4 composite sample. UV–Vis DRS spectroscopy analysis revealed that the composite (2.08 eV) sample had a reduced bandgap compared to other samples. The photocatalytic properties of the prepared samples were tested in the presence of organic methylene blue (MB) and antibiotic tetracycline (TC) pollutants under visible light illumination. The hybrid composite catalyst exhibited enhanced photocatalytic degradation efficiency of MB (88%) and TC (89%) pollutants at elevated rate constants of 0.0128 and 0.01174 min−1, respectively. The improved catalytic performance of the composite catalyst is due to the heterojunctions between g-C3N4 and BiVO4 that successfully reduced the rate of charge carrier recombination in the catalyst system. Scavenger experiments revealed that O2●— and h+ radicals played a main role in the degradation of the chemical pollutants. The developed g-C3N4/BiVO4 heterostructured catalyst is a suitable candidate for removing contaminants from industrial wastewater because of its facile fabrication and exceptional photocatalytic activity under visible light irradiation.

Ru(N^N)3-docked cationic covalent organic frameworks for enhanced sulfide and amine photooxidation.

Covalent organic frameworks (COFs) have emerged as significant candidates for visible-light photocatalysis due to their ability to regulate performance which is achieved through the careful selection of building modules, framework conjugation, and post-modification. This report focused on the efficient transformation of an imine-linked I-COF into a π-conjugated quinoline-based Q-COF, which enhanced both the chemical stability and conjugation of the network. By methylating the pyridyl groups in the Q-COF, an N+-COF was obtained. Subsequently, the Ru(N^N)3-photosensitizer ([Ru(dcbpy)3]4-) was incorporated into the channels of the cationic N+-COF through electrostatic interactions, resulting in the formation of [Ru(dcbpy)3]4-⊂N+-COF. This composite exhibited exceptional photocatalytic activity, demonstrating high yields and selectivity in the oxidation of sulfides or amines to their respective products.

Ultrathin origami accordion‐like structure of vacancy‐rich graphitized carbon nitride for enhancing CO2 photoreduction

AbstractRetaining the ultrathin structure of two‐dimensional materials is very important for stabilizing their catalytic performances. However, aggregation and restacking are unavoidable, to some extent, due to the van der Waals interlayer interaction of two‐dimensional materials. Here, we address this challenge by preparing an origami accordion structure of ultrathin two‐dimensional graphitized carbon nitride (oa‐C3N4) with rich vacancies. This novel structured oa‐C3N4 shows exceptional photocatalytic activity for the CO2 reduction reaction, which is 8.1 times that of the pristine C3N4. The unique structure not only prevents restacking but also increases light harvesting and the density of vacancy defects, which leads to modification of the electronic structure, regulation of the CO2 adsorption energy, and a decrease in the energy barrier of the carbon dioxide to carboxylic acid intermediate reaction. This study provides a new avenue for the development of stable high‐performance two‐dimensional catalytic materials.

Novel Ag-bridged dual Z-scheme g-C3N4/BiOI/AgI plasmonic heterojunction: Exceptional photocatalytic activity towards tetracycline and the mechanism insight

Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical. Herein, aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers and unstable structure, a novel Ag-bridged dual Z-scheme g-C3N4/BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method. Results showed that Ag-AgI nanoparticles and three-dimensional (3D) BiOI microspheres were decorated highly uniformly on the 3D porous g-C3N4 nanosheet, resulting in a higher specific surface area and abundant active sites. The optimized 3D porous dual Z-scheme g-C3N4/BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline (TC) in water with approximately 91.8% degradation efficiency within 165 min, outperforming majority of the reported g-C3N4-based photocatalysts. Moreover, g-C3N4/BiOI/Ag-AgI exhibited good stability in terms of activity and structure. In-depth radical scavenging and electron paramagnetic resonance (EPR) analyses confirmed the relative contributions of various scavengers. Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework, fast electron transfer of dual Z-scheme heterojunction, desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas. Therefore, the 3D porous Z-scheme g-C3N4/BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation. The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications.

Construction of dual Z-scheme UNiMOF/BiVO4/S-C3N4 photocatalyst for visible-light photocatalytic tetracycline degradation and Cr(VI) reduction

Rapid recombination of the photogenerated carrier, a limited range of photoexcitation, and unsatisfactory photocatalytic activity are the limiting factors in photocatalytic applications. Accelerating photogenerated carrier transfer and constructing surface active sites have become critical tasks. In this study, a dual Z-scheme UNiMOF/BiVO4/S-C3N4 (NBSCN) photocatalyst with a 2D/3D/2D structure was successfully constructed. Under visible-light irradiation, NBSCN outperforms single and binary composites in photocatalytic tetracycline photodegradation and Cr(VI) photoreduction due to the synergistic effect of adsorption and photocatalysis. The maximum photocatalytic efficiency of tetracycline (90.1 %) and Cr(VI) (93.6 %) in 120 min was achieved by NBSCN-20 %. The exceptional photocatalytic activity of NBSCN-20 % can be attributed to the large specific surface area, increased active sites, improved visible-light absorption ranges, and the construction of heterojunctions. The fabricated dual Z-scheme heterojunction at the interface of NBSCN reduces the recombination rate of photogenerated carriers and widens the range of light absorption. NBSCN-20 % exhibits excellent stability in the process of cyclic experiments. On the basis of the results, the feasibility of the dual Z-scheme mechanism is proposed. This work demonstrates that NBSCN-20 % photocatalyst has promising application prospects in removing heavy-metal ions and organic pollutants from aqueous environments.

Synthesis of solar light driven nanorod-zinc oxide for degradation of rhodamine B, industrial effluent and contaminated river water

Surface water contamination by various dyes and pigments is a global problem caused by rapid industry, particularly textile/dyeing. Bangladesh's export-oriented textile sector has exploded in recent decades, polluting local waterways significantly. In this study, nano-ZnO were prepared using surfactant-assisted sol–gel, hydrothermal and thermal methods. SEM, XRD, reflectance spectrophotometer, EDS and adsorption tests were used to characterize the synthesized nano-ZnO. BET isotherms were used to determine the surface area, pore volume, and pore size of the as-prepared nano-ZnO. The mixed surfactant assisted-sol gel method produced nanorod-ZnO, whereas the hydrothermal and/or thermal methods yielded clusters of needles ZnO, as proven by SEM images. XRD data revealed that the synthesized nanorod-ZnO had a mainly wurtzite crystalline structure and their size was estimated using the Scherrer equation to be about 23.90 nm. EDS spectra confirmed the synthesis of pure nanorod-ZnO. Using a UV–visible reflectance spectrophotometer, the band gap energy of the as-prepared nanorod-ZnO was found to be 3.35 eV. According to BET isotherms, the BET and Langmuir surface areas were 4 and 5.4 m 2 /g, respectively. Prior to analyzing photodegradation, the RB was adsorbing in the presence of various doses of the nanorod-ZnO in the dark, but no adsorption was observed. The photocatalytic activities of the synthesized nano-ZnO were compared to TiO 2 (anatase) for the degradation of RB in an aqueous system under solar light, UV, fluorescence, and tungsten filament light irradiation. Nanorod-ZnO showed exceptional photocatalytic activity in degrading RB in an aqueous solution under solar light irradiation. The results suggest that 0.01 g/50 mL nanorod-ZnO with a solution pH of 7.8 is the best combination for complete degradation of 2.00 × 10 -5 M RB under solar light irradiation. When nano-ZnO was exposed to light, the inhibiting effect of ethanol and/or tert -butanol on the degradation of RB confirmed the formation of mostly hydroxyl free radicals. The synthesized nanorod-ZnO shown substantial photocatalytic activity in the removal of pollutants from industrial effluents and contaminated river water under solar light irradiation. A mechanism of excellent photocatalytic activity of the nanorod-ZnO is discussed.

Hierarchical SiO2@FeCo2O4 core–shell nanoparticles for catalytic reduction of 4-nitrophenol and degradation of methylene blue

Water contamination is a significant environmental issue in the modern era. Two of the most prominent sources of water pollution are the dyestuff and pharmaceutical industries, and their discharge poses a substantial threat to the ecosystem due to adverse human and environmental health impacts. The methylene blue (MB) dyes and 4-nitrophenol (4-NP) were degraded in this work employing a hierarchical SiO2@FeCo2O4 (SiO2@FCO) core–shell catalyst. The capacity of conventional wastewater treatment systems to treat non-biodegradable contaminants is limited. Hydrothermal synthesis of the hierarchical SiO2@FCO core–shell catalysts was employed to remove 4-NP and degrade MB. The hierarchical SiO2@FCO core–shell properties were investigated using a range of techniques, including FTIR, XRD, XPS, TEM, SEM, and BET. The photocatalytic activity of hierarchical SiO2@FCO core–shell nanoparticles eliminating 4-NP and degrading MB is exceptional when exposed to UV light. The SiO2@FCO catalyst displayed excellent catalytic activity and recycling properties while eliminating 4-NP in the presence of light. Hierarchical SiO2@FCO core–shell nanoparticles has exceptional photocatalytic activity, removing 99.6% of MB in 15 min and more than 99.4% of 4-NP in 10 min.

Expediting photocarrier separation in Ta3N5@CaTaO2N heterostructures with seamless interfaces for photocatalytic water oxidation under visible light

The separation of photocarriers (e- and h+) is of critical importance in initiating efficient catalytic reactions over semiconductor-based photocatalysts. Although heterostructures have been frequently built to separate photocarriers, the lack of proper heterogeneous interfaces greatly limits their efficacies. Here, we show that excellent heterogeneous interfaces can be built for in situ fabricated Ta3N5 @CaTaO2N heterostructures. These interfaces are characterized by perfectly matching (020) crystal facets of Ta3N5 and CaTaO2N, offering ideal channels for charge transportation. As revealed by both experimental and theoretical analysis, these seamless interfaces enable rapid spatial photocarrier separation, which in turn, contribute to exceptional photocatalytic activity. Under optimal conditions, Ta3N5 @CaTaO2N heterostructures achieve apparent quantum efficiency as high as 14.52% at 420 ± 20 nm for O2-evolution, substantially surpassing Ta3N5, CaTaO2N, and their mixtures. These results not only justify the importance of heterogeneous interfaces for photocarrier separation but also invigorate more attention upon heterostructures towards efficient solar water splitting.

Donor-acceptor conjugated heptazine polymers: Boosting the Cr(VI) photoreductions via heteroatom engineering

Due to the high photoinduced charge seperations, donor-acceptor (D-A) conjugated heptazine polymers containing fluorene donors have attracted much attention for their high photocatalytic degradations towards organic pollutants. To have an insight into the impact of the electron-donating ability of the donor moieties, herein three D-A conjugated heptazine polymers containing fluorene-like donors with different heteroatoms (dibenzofuran, carbazole, dibenzothiophene, named as CHP-O, CHP-N and CHP-S, respectively) have been synthesized through reversible Friedel-Crafts reactions. Interestingly, the photocatalytic evaluations reveal that all three compounds exhibit an exceptional photocatalytic reduction activity towards hexavalent chromium (Cr(VI)) with the conversion rates of 97%, 95% and 90% for CHP-O, CHP-N and CHP-S, respectively, upon the visible-light irradiation, which is attributed to the narrow band gap and high charge transfer efficiency in the crystalline conjugated systems.

Generating a captivating S-scheme CuBi2O4/CoV2O6 heterojunction with boosted charge spatial separation for efficiently removing tetracycline antibiotic from wastewater

In this work, a captivating S-scheme CuBi2O4/CoV2O6 heterojunction was innovatively constructed by in situ growing CoV2O6 nanoparticles on the surface of CuBi2O4 microrods. Of note, the unique CuBi2O4 microrods served as an outstanding substrate to achieve the uniform loading of CoV2O6 nanoparticles. Compared with neat CoV2O6 and CuBi2O4, as expected, the resulting CuBi2O4/CoV2O6 illustrated significantly boosted photocatalytic efficiency for degrading tetracycline (TC) under visible light illumination. More impressively, the optimized CuBi2O4(30 wt%)/CoV2O6 manifested the best TC removal rate of 0.01328 min−1 after 120 min of reaction, which was roughly 33.2 and 14.4 times larger than those of neat CoV2O6 and CuBi2O4, separately. Such an exceptional photocatalytic activity was mainly ascribed to the expedited the charge spatial detachment and transport, and synchronously reserved the strong redox ability driven by the established S-scheme heterojunction between CoV2O6 and CuBi2O4. Moreover, the reactive species scavenging tests and electron spin resonance analysis substantiated that the superoxide radicals combined with photogenerated holes were unquestionably responsible for removing TC. Eventually, the possible degradation mechanism and pathways of TC over CuBi2O4/CoV2O6 were also put forward.

Sustainable and green synthesis of novel acid phosphatase mediated platinum nanoparticles (ACP-PtNPs) and investigation of its in vitro antibacterial, antioxidant, hemolysis and photocatalytic activities

Clean water is a worldwide major problem and several conventional strategies are accompanied with a number of drawbacks. To overcome this problem, new methods and materials have been introduced to address the problem of water purification. Platinum nanoparticles (PtNPs) are a fascinating and appealing research area as they are a series of effective environmental and biomedical applications. The present study is the first to report an immediate, cost-effective, and eco-begin synthesis of ACP-PtNPs using acid phosphatase of Rumex dentatus seeds extract. Acid phosphatase performed an imperative role in the stability, and capping of ACP-PtNPs. The ACP-PtNPs were characterized by different techniques, including UV–visible spectroscopy, XRD, FTIR, XPS, HRTEM, EDS, SEM and DLS analysis. ACP-PtNPs were brown-colored and mostly spherical in shape, with ultra-small particle size (1–7 nm). The onset of a plasmon peak at 295 nm confirmed the formation of ACP-PtNPs. The as-prepared nanoparticles were tested for the photocatalytic degradation of methylene blue (MB) under visible light irradiation. The results showed that ACP-PtNPs exhibited remarkable photocatalytic efficiency by degrading 99% of MB only in 28 min. ACP-PtNPs were also showed strong photoinhibition efficiency against gram negative bacteria. ACP-PtNPs were found to be harmless to normal healthy RBCs in the cytotoxicity investigation. Furthermore, ACP-PtNPs also possessed superb antioxidant activity whereby effectively scavenging 88% of stable and harmful 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical. These exceptional photocatalytic and biomedical activities may be attributed to the trivial size and large surface area of ACP-PtNPs.

Enhanced photocatalytic degradation of rhodamine B and malachite green employing BiFeO3/g-C3N4 nanocomposites: An efficient visible-light photocatalyst

A simple sonication technique was used to synthesize the g-C3N4 nanoparticle decorated with BiFeO3. Various techniques, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Transmission electron microscope (TEM), UV–Vis diffuse reflection spectroscopy (UV-DRS), and X-ray photoelectron spectroscopy (XPS) were used to analyze the structural and optical characteristics of BiFeO3/g-C3N4 composites. In comparison to pristine g-C3N4, the synthesized BiFeO3/g-C3N4 composite displays exceptional photocatalytic activity. The increased photocatalytic activity of the BiFeO3/g-C3N4 composite was assigned mostly to the separation of photogenerated electron-hole (e-&h+) pairs caused by charge migration. A potential photocatalytic process for dye degradation was proposed over a BiFeO3/g-C3N4 composite. The BiFeO3/g-C3N4 composite possessed the highest photodegradation of 96% for rhodamine B (RhB) and 86% for malachite green (MG) dye in a short time, like 40 min and 50 min, respectively, at pH 3 under visible light exposure. For different concentrations and doses, the photocatalytic degradation of RhB and MG followed a pseudo-first-order rate with K values of 0.079 min−1 and 0.039 min−1, respectively. Furthermore, BiFeO3/g-C3N4 demonstrated high photo-stability for organic dye degradation during five consecutive cycles with little effect on photocatalytic activity. As a consequence, the organic dyes were oxidized into non-toxic molecules like water (H2O) and carbon dioxide (CO2). Hydroxyl radicals (OH•) and superoxide radicals O2-∙ have been found as the reactive species in the photocatalytic process over BiFeO3/g-C3N4.

Synthesis and characterization of Ag/Ce1-XBiXZnO composites hosted α-β/Bi2O3 as highly efficient catalysts for degradation of cationic and anionic dyes

Removal of organic impurities from wastewater has become concern for humanity. Herein, to improve the Ag/ZnO performance in degradation of organic dyes catalyst was modified by Ce and Bi in order to form an interface or heterojunction between catalyst component, which can suppress the rapid e-/h± recombination in ZnO. Where, Ag/Ce1-XBiXZnO composites (x = 0, 0.1, 0.3, and 0.5) were synthesized using CTAB assisted hydrothermal/deposition method. Ag/Ce1-XBixZnO catalysts exhibited exceptional photocatalytic activity for the degradation and mineralization of cationic and anionic dyes under UV and visible light irradiation. The trend in the photocatalytic degradation of dyes using Ag/Ce1-XBiXZnO depends on amount of Bi doped. The maximum photodegradation of the Rhodamine dye was achieved up to 99.9% using Ag/Ce0.1Bi0.9ZnO photocatalyst with absolute mineralization efficiency 77.9% however, Ag/Ce0.3Bi0.7ZnO showed superior photocatalytic activity in degradation of Indigo with 99.8 % with absolute mineralization efficiency 64.6%. The characterization results of various techniques (viz., XRD, XPS, H2TPR, PL and DRS) revealed that the incorporation of different amount of Bi in the Ag/Ce1-XBiXZnO catalysts is most beneficial for decreasing band gap (2.48–2.58 eV), creation of oxygen vacancy, improvement of Ag dispersity, and change the ratios of different phases: α-/β-Bi2O3, CeO2/Ce2O3, Ag/AgOy on the catalyst surface. It is also proposed that the lower band gap of Ag/Ce1-XBiXZnO catalysts and the creation of oxygen vacancies provide methods to suppress the rate of recombination of photoinduced electrons and holes as was confirmed by PL analysis. In addition, high resolution transmission and scanning electron microscopies analyses establish the formation heterojunctions between composite phases. The change of the mentioned above physicochemical characteristics of Ag/Ce1-XBiXZnO catalysts by Bi doping may be affected on their capabilities to generate and transform more e- and h+ to O2 and H2O respectively, to create •O2, and •OH active radicals for dyes degradation. Trapping experiment indicates that •O2, and •OH radicals have significant role in the degradation of RhB over Ag/Ce0.1Bi0.9ZnO. However, •O2 radicals were the major species responsible for the degradation of Indigo dye over Ag/Ce0.7Bi0.3ZnO. Here, it is suggested that the ratio of photogenerated •O2/•OH by Ag/Ce1-XBiXZnO depends also on the amount of Bi in the catalysts, which results in the observed differences in their catalytic performances. The reusability test demonstrated that Ag/Ce1-XBixZnO catalysts have a decent stability.

An effective strategy for improving charge separation efficiency and photocatalytic degradation performance using a facilely synthesized oxidative TiO2 catalyst.

Titanium dioxide (TiO2) has attracted enormous interest in abundant photocatalytic reactions, but its photocatalytic efficiency is limited by its wide bandgap and the rapid recombination of electron-hole pairs. To overcome the disadvantages of its rapid electron-hole recombination rate, herein, oxidative TiO2 was one-step fabricated using potassium permanganate (KMnO4), exhibiting improved charge separation efficiency and photocatalytic degradation performance towards methyl orange (MO). Remarkably, the first-order photodegradation rate of oxidative TiO2 is 3.68 times higher than that of pristine TiO2 under the irradiation of simulated sunlight and 2.15 times higher under ultraviolet light. This exceptional photocatalytic activity is attributed to the additional oxygen doped into the interstices of the TiO2 lattice, creating impurity states in the bandgap acting as trapping sites, thus facilitating charge separation. This work provides a promising strategy for the insertion of O atoms into the TiO2 lattice and expands the photocatalytic application of the related materials.

A mesh-like BiOBr/Bi2S3 nanoarray heterojunction with hierarchical pores and oxygen vacancies for broadband CO2 photoreduction

Distinctive hierarchitectures composed of mesh-like Bi2S3 nanoarrays on oxygen-vacancy-rich BiOBr nanoplates were developed for exceptional photocatalytic activity and selectivity in CO2-to-CO conversion.

Exceptional Photocatalytic Activities of rGO Modified (B,N) Co-Doped WO3 , Coupled with CdSe QDs for One Photon Z-Scheme System: A Joint Experimental and DFT Study.

Artificial Z‐scheme, a tandem structure with two‐step excitation process, has gained significant attention in energy production and environmental remediation. By effectively connecting and matching the band‐gaps of two different photosystems, it is significant to utilize more photons for excellent photoactivity. Herein, a novel one‐photon (same energy‐two‐photon) Z‐scheme system is constructed between rGO modified boron‐nitrogen co‐doped‐WO3, and coupled CdSe quantum dots‐(QDs). The coctalyst‐0.5%Rh x Cr2O3(0.5RCr) modified amount‐optimized sample 6%CdSe/1%rGO3%BN‐WO3 revealed an unprecedented visible‐light driven overall‐water‐splitting to produce ≈51 µmol h−1 g−1 H2 and 25.5 µmol h−1 g−1 O2, and it remained unchanged for 5 runs in 30 h. This superior performance is ascribed to the one‐photon Z‐scheme, which simultaneously stimulates a two photocatalysts system, and enhanced charge separation as revealed by various spectroscopy techniques. The density‐functional theory is further utilized to understand the origin of this performance enhancement. This work provides a feasible strategy for constructing an efficient one‐photon Z‐scheme for practical applications.