Selenoviologens‐appendant metallacycles M1 (rhomboid) and M2 (hexagonal) were synthesized and utilized in electrochromism and photocatalysis, as reported in the Research Article (e202209054) by Gang ...He et al. The highly stable radical cations and long‐lived charge separation states of the selenoviologens (SeV2+) originate from the metallacyclic effect. Their properties were validated by femtosecond transient absorption (fs‐TA), demonstrating the vital role of the metallacycle in organic photocatalytic reactions.
In the recent years, zinc oxide has emerged as one of the promising alternate materials to titania for photocatalytic applications due to its several advantages properties. This review recapitulates ...the ongoing advancement in the field of ZnO-based heterojunctions as visible light responsive photocatalysts for energy conversion (hydrogen evolution) and environmental remediation (pollutants degradation) applications. After a short introduction about zinc oxide materials, the various approaches utilized in the design and development of efficient ZnO-based nanoheterostructures has been discussed in detail. Specifically, strategies such as coupling ZnO with other semiconductors, supporting on carbonaceous materials, decorating with noble metal nanoparticles, doping with heteroatoms and engineering defects in the semiconductor material have been elaborated with a particular emphasis on hydrogen energy and organic pollutants removal. Finally, the future perspective of this material has been highlighted. This comprehensive review not only summarizes the recent literature in this topic, but also provides a detailed insight on the scope of this material for hydrogen energy and environmental remediation applications.
Chloramphenicol sodium succinate (CAP, C15H15Cl2N2 Na2O8) is a broad-spectrum antibiotic exhibiting activity against both Gram-positive and Gram-negative bacteria as well as other groups of ...microorganisms only partially removed by conventional activated sludge wastewater treatment plants. Thus, CAP and its metabolites can be found in effluents. The present work deals with the photocatalytic degradation of CAP using TiO2 as photocatalyst. We investigated the optimization of reaction contact time and concentration of TiO2 considering CAP and its by-products removal as well as effluent ecotoxicity elimination. Considering a CAP real concentration of 25mgL−1, kinetic degradation curves were determined at 0.1, 0.2, 0.4, 0.8, 1.6 and 3.2gL−1 TiO2 after 5, 10, 30, 60 and 120min reaction time. Treated samples were checked for the presence of by-products and residual toxicity (V. fischeri, P. subcapitata, L. sativum and D. magna). Results evidenced that the best combination for CAP and its by-products removal could be set at 1.6gL−1 of TiO2 for 120min with an average residual toxicity of approximately 10%, that is the threshold set for negative controls in most toxicity tests for blank and general toxicity test acceptability.
•CAP and its metabolites are not easily removed by activated sludge plants.•Degradation kinetics and toxicity were investigated to look for the best conditions.•Photo-oxidation for 120min at 1.6gL−1 of TiO2 completely removed CAP and by-products.•The effluent residual toxicity after treatment was approximately of 10%.
The Cover Feature depicts a schematic soccer game representing two strategies for the radical C‐H substitution reaction catalyzed by naphthalene diimides (NDIs): a consecutive photoinduced electron ...transfer (conPET) and an electro photoinduced electron transfer (electroPET). A ball (electron) coming from different sources reaches a comfortable spectator (the substrate) after passing through the players (NDI catalyst). In their Full Paper, S. Caby et al. studied a family of NDI photocatalysts comparing a “pure” photochemical and an electro‐photochemical transformation. They identify a system that has the potential to be applied in both approaches and recognize the excitation of radical anion of NDI as the key event. Both approaches produce similar yields and reaction rates, although a conPET process shows in principle a simpler setup and more tolerance to a poor catalyst solubility, the electroPET process improves selectivity and gives more room for optimization. More information can be found in the Full Paper by S. Caby et al.
•A comparative study on ZnO based binary/multiple nanocomposite and heterojunction photocatalysts.•Hydrothermally produced ZnO/CuO heterostructure shows the best photocatalytic action.•Thermal growth ...of γ-Fe2O3-ZnO-biochar multiple nanocomposite exhibited the highest photocatalytic activity.•Overall, the best photocatalytic action observed for the ZnO/CuO binary heterostructure.
Highly efficient ZnO based double and multiple photocatalyst heterojunctions and nanocomposites.
Display omitted
ZnO based binary and multiple heterojunction/nanocomposite photocatalysts get profound attentions due to its solving the world crises of energy supply and utilizing sun power potential to generate H2, coal oil materials and degradation of various pollutants. In the past decade, a number of motivating fulfillments have been done on the ZnO based heterojunction/nanocomposite photocatalysts, which are significant materials for the photocatalytic process. However, the proficiency of the photocatalysis stands low because of the swift electron-hole reincorporation and low light usage. So, to solve these issues huge efforts have been made considered. Specially, the produced high quality ZnO based heterojunction/nanocomposite photocatalysts are exhibited in order to have higher photocatalytic action due to the spatial dissociation of photo-induced electron-hole couples. The aim here is to clarify increment process of the photocatalytic activity of the ZnO based binary and multiple heterojunction/nanocomposite photocatalysts, and also methodically outlines recent efficient developments related to the sketch and production of ZnO based heterojunction/nanocomposite photocatalysts. They are very encouraging for a number of variety supplications in UV–Vis light photocatalytic area, regarding with photocatalytic hydrogen generation, CO2 depletion, environmental restitution, and organic photosynthesis. Particularly, attentions have given to the fundamental principles of the various proficient ZnO based heterojunction/nanocomposite photocatalysts and recent efforts about the improvement of ZnO based heterojunction/nanocomposite photocatalysts for variety photo-degradation supplications. Furthermore, it is also provided that a brief summary and perspective on the improvements and as well as next directions in the field of ZnO based heterojunction/nanocomposite photo-catalysts. Finally, the recent researches about the ZnO based binary and multiple heterojunction/nanocomposite photocatalysts are compared in terms of their photocatalytic performance. and Amongst all, the hydrothermally produced ZnO/CuO p-n heterojunction has shown the highest photocatalyst performance of 92.62% in 5 min.
Display omitted
•Carbonized eggshell membranes (CEMs) were used as bio-templates.•Novel 3D hierarchical carbon quantum dots (CQDs)/BiOCl/CEMs were fabricated.•BiC-0.05 exhibited superior removal ...efficiency of several organic pollutants.•The removal was boosted by synergistic effect of adsorption and photocatalysis.•The presence of OVs and CQDs account for the boosted photocatalytic activity.
A series of carbon quantum dots (CQDs)-decorated BiOCl/carbonized eggshell membrane (CEM) composites were synthesized with CEMs as bio-templates. The obtained composites, especially BiC-0.05, exhibited superior removal efficiencies of several organic pollutants, i.e. tetracycline hydrochloride (TC), Rhodamine B (RhB), and o-nitrophenol (NP). Approximately, 98% of TC was removed after 30 min dark adsorption and subsequent 30 min visible-light-initiated photocatalytic degradation. BiC-0.05 was also utilized to treat actual industrial wastewater and could reduce 73.1% COD, in comparison to 49.9% with the use of BiOCl. The boosted removal efficiencies were achieved by synergistic effect of adsorption and photocatalysis, where cooperative contribution of oxygen vacancies (OVs), CEMs and CQDs enabled faster charge migration and more effective separation of photogenerated charge carriers. Electron spin resonance (ESR) and trapping experimental results showed that superoxide radical (O2−), along with holes (h+) and hydroxyl radical ( OH) would take part in photocatalytic degradation process. The intermediates of TC and its possible degradation pathway during the photocatalytic reaction were also studied. Our work developed a novel strategy by integrating carbon nanomaterials derived from bio-waste to design efficient photocatalysts for remediation of organic contaminants via adsorption – photocatalysis synergism and OVs – CQDs cooperation.
Display omitted
•Co3O4 as a heat source in composite system can generate heat by absorbing Vis-NIR light.•High-frequency photons are converted into heat to accelerate interfacial charge ...transfer.•S-scheme retains carriers with high redox potentials converted from low-frequency photons.
The development of photocatalysts that maximize the use of solar spectra for photocatalysis for obtaining more efficient photocatalysts is urgently needed. Herein, the core–shell Co3O4@ZnIn2S4 S-scheme heterojunction was synthesized for achieving high-efficient photothermal-assisted photocatalytic hydrogen (H2) performance under full solar-spectrum irradiation. Notably, photocatalytic H2 production tests indicate that the as-prepared optimal Co3O4@ZnIn2S4 sample (CO@ZIS-20) exhibits impressive H2 production rates of about 18.9 and 9.8 mmol h−1 g−1 under AM 1.5G and real sunlight irradiation, respectively. The effect of the reaction solution temperature induced by the photothermal effect on the photocatalytic activity in solid–liquid reactions was also investigated. Furthermore, the results of the characterization analysis revealed that high-frequency photons dominate photocatalytic reactions while low-frequency photons are converted into heat to improve photocatalytic reactions. This study provides effective design ideas of developing high-activity photothermal-assisted photocatalysts for realizing solar energy conversion.
Thermo-photo catalysis, which is the catalysis with the participation of both thermal and photo energies, not only reduces the large energy consumption of thermal catalysis but also addresses the low ...efficiency of photocatalysis. As a whole greater than the sum of its parts, thermo-photo catalysis has been proven as an effective and promising technology to drive chemical reactions. In this review, we first clarify the definition (beyond photo-thermal catalysis and plasmonic catalysis), classification, and principles of thermo-photo catalysis and then reveal its superiority over individual thermal catalysis and photocatalysis. After elucidating the design principles and strategies toward highly efficient thermo-photo catalytic systems, an ample discussion on the synergetic effects of thermal and photo energies is provided from two perspectives, namely, the promotion of photocatalysis by thermal energy and the promotion of thermal catalysis by photo energy. Subsequently, state-of-the-art techniques applied to explore thermo-photo catalytic mechanisms are reviewed, followed by a summary on the broad applications of thermo-photo catalysis and its energy management toward industrialization. In the end, current challenges and potential research directions related to thermo-photo catalysis are outlined.
Display omitted
•The application of ZIF/ZIF derivative based composite photocatalysts was reviewed.•Special attention has been paid to the catalytic mechanism.•The synergistic effects between the ...components are discussed.•The challenges and opportunities in this interesting field are presented.
To solve the problem of the global energy shortage and the widespread pollution of the environment, semiconductor photocatalytic technology has been widely studied. Zeolitic imidazolate frameworks, a sub-family of metal-organic frameworks, have emerged as potential candidates for photocatalysis due to their intrinsic porous characteristics, abundant functionalities, rapid electron transfer ability, and exceptional thermal and chemical stabilities. Besides, a thermal treatment of zeolitic imidazolate frameworks can result to functional materials that have the similar structure characteristic, but superior light sensitivity and charge transfer properties. Moreover, the photocatalytic activity of zaeolitic imidazolate frameworks and their derivatives can be largely improved by combining photoactive semiconductors/ molecules which serve as light harvesting centers/electronic mediators. This paper presents a first review of the application of zaeolitic imidazolate frameworks and their derivatives -based materials for visible-light-induced photocatalytic hydrogen evolution and pollutants treatment. The representative studies are carefully summarized and discussed. Special emphasis is given to the synergistic effects between the components in the composite catalyst for enhanced photocatalysis. At the end of this review, the current achievements together with major challenges in the field are discussed and the next possible development directions are proposed.
Nitrate and its metabolites as common pollutants in water had attracted widespread attentions. Converting nitrate to nontoxic and harmless nitrogen via photocatalysis was a promising approach. In ...this study, a novel Z-scheme NH2-MIL-101(Fe)/BiVO4 heterojunction was successfully prepared. As-prepared Z-scheme heterojunction along with built-in electric field facilitated the charge separation and enhanced the photocatalytic activity in nitrate reduction. The results showed that 0.10-MBiVO photocatalyst exhibited the highest nitrate removal rate of 94.8% (initial concentration 100 mgN/L) and final selectivity to N2 of 93.4% in 50 min under ultraviolet irradiation. Moreover, formic acid was proved as better hole scavenger compared with methanol and oxalic acid. And the concentration of formic acid had significant influence on the process of nitrate photocatalytic reduction. 0.10-MBiVO photocatalyst exhibited excellent reusability in the recycling tests, indicating its great potential in practical application of nitrate photocatalytic removal. The mechanism of the enhancement as well as reaction pathways for nitrate photocatalytic reduction on NH2-MIL-101(Fe)/BiVO4 were comprehensively explored and described at the end.
Display omitted
•Novel Z-scheme NH2-MIL-101(Fe)/BiVO4 heterojunction was synthesized.•0.10-MBiVO photocatalyst exhibited the highest nitrate removal rate.•Mechanism of the enhancement has been explored and discussed.•The possible reaction pathway has been proposed.
PDF
