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Mang Zheng

Bio: Mang Zheng is an academic researcher from Chinese Ministry of Education. The author has contributed to research in topics: Catalysis & Coupling reaction. The author has an hindex of 1, co-authored 4 publications receiving 5 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a Cu/C-700/Pd nanocomposite is obtained by loading trace Pd2+ onto carbon support derived from a novel mononuclear copper complex, {[Cu(POP)2(Phen)2]BF4}.

7 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used environmentally friendly catalysts for self-coupling of benzylamine at a low temperature of 323 K in air, achieving conversion and selectivity values of up to 99% and 98%, respectively.
Abstract: Benzylamine coupling is a very important reaction for the synthesis of imine but still faces many challenges. Herein, we present a highly effective strategy towards the coupling reaction by using environmentally friendly catalysts. These catalysts are composed of Cu/Cu2O/Cu3N heterostructures supported by C3N4 tubes and the composites were synthesized by one-step hydrothermal treatment followed by calcination. Cu2O, Cu3N, and C3N4 all are responsive to visible light and the heterojunction formed can greatly enhance the charge separation. When used as photocatalysts for oxidative self-coupling of benzylamine at a low temperature of 323 K in air, Cu/Cu2O/Cu3N/C3N4 was able to give conversion and selectivity values of up to 99% and 98%, respectively. The high efficiency of the catalysts is attributable to their ability to generate large quantities of free radicals (such as ·OH and ·O2−) under visible-light irradiation.

6 citations

Journal ArticleDOI
TL;DR: In this article, the authors developed the effective synergistic catalysis reaction of Fenton and photocatalysis based on a loofah sponge-like Fe2Ox/C nanocomposite, which exhibits excellent nitrobenzene photocatalytic degradation property.
Abstract: Fenton or photocatalytic degradations of organic contaminants are recognized as promising approaches to address the increasing environmental pollution issues. Herein, we develop the effective synergistic catalysis reaction of Fenton and photocatalysis based on a loofah sponge-like Fe2Ox/C nanocomposite, which exhibits excellent nitrobenzene photocatalytic degradation property. It is noted that Fe2O3 nanoparticles with surface Fe2+ species were encapsulated with an ultrathin carbon layer (denoted as Fe2Ox/C) via a supramolecular self-sacrificing template and following thermal treatment process. The experimental results indicated that the thin layer carbon coating not only inhibited the Fe iron leaching from the Fe2Ox but also prompted the separation and transferring of electrons-hole pairs. The introduction of Fe2Ox/C enables the Fenton reaction to induce a rapid Fe2+/Fe3+ cycle, and meanwhile, together with the photocatalytic reaction to produce continuous active substances for the subsequent degradation catalytic reaction without successive H2O2, resulting in the inexpensive and the effective photocatalytic procedure. As a result, 100% nitrobenzene (100 mg/L) was degraded and 97% of the organic carbon was mineralized in 90 min using the Fe2Ox/C (0.1 g/L) at a low H2O2 dosage (0.50 mM), under air mass (AM) 1.5 irradiation. Theoretical calculations confirmed that the Fe2Ox/C-600 with thin carbon layer promoted the dissociation of H2O2 and the ·OH desorption. The synergistic catalysis of this work may provide new ideas for low-cost and more efficient treatment of pollutants.

4 citations


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Journal ArticleDOI
TL;DR: Among the diverse graphitic carbon nitride (CN) nanostructures, CNNTs are currently attracting increasing interest due to the appealing properties of CN and the geometric advantages of one-dimensional (1D) nanotubes as discussed by the authors.
Abstract: Among the diverse graphitic carbon nitride (CN) nanostructures, CN nanotubes (CNNTs) are currently attracting increasing interest due to the appealing properties of CN and the geometric advantages of one-dimensional (1D) nanotubes. CN is a metal-free photocatalyst and has the advantages of exceptional electronic band structure, rich nitrogen content, and high physicochemical stability. Nanotubes have a unique 1D hollow nanostructure, and they provide large surface area, high aspect ratio, electron mobility along the axial direction, and quantum confinement effects. Therefore, CNNTs and CNNT-based materials have been extensively explored in many energy- and environment-related fields. In this review, the functional merits of CNNTs and recent progress in the precursor-based synthesis of CNNTs are discussed. Besides, the corresponding applications of CNNT-based nanomaterials are summarized, such as photocatalytic H2 production, pollutant degradation, and CO2 reduction. Moreover, the modification strategies of CNNTs using elemental doping, texture tailoring, and heterojunction engineering are comprehensively discussed. Finally, the future challenges and opportunities of CNNT-based nanostructures are proposed. With the rapid development of materials science and technology, more efforts need to be devoted toward promoting the advanced functionalities and promising applications of CNNT-based materials.

62 citations

Journal ArticleDOI
Gang Zhao1, Xijin Xu1
TL;DR: In this paper, the authors summarize the recent application research on cocatalysts in the field of photocatalysis, starting from the types, preparation methods, and reaction mechanisms among others, to remind researchers of the matters needing attention when using cocatalysis.
Abstract: With the rapid development of society, the burden of energy and the environment is becoming more and more serious. Photocatalytic hydrogen production, the photosynthesis of organic fuel, and the photodegradation of pollutants are three effective ways to reduce these burdens using semiconductor photocatalysts. To improve the reaction efficiency of photocatalysts, a small amount of cocatalyst is often added when photocatalysts participate in the synthesis or decomposition reaction. The addition of this small amount of cocatalyst is like a finishing touch, significantly increasing the activity of the photocatalysts. However, in our common study of photocatalysis, we often pay attention to the study of photocatalysts but ignore the study of cocatalysts. Herein, we summarize the recent application research on cocatalysts in the field of photocatalysis, starting from the types, preparation methods, and reaction mechanisms among others, to remind researchers of the matters needing attention when using cocatalysts.

27 citations

Journal ArticleDOI
TL;DR: In this article , the authors identify the challenges and future prospects of g-C 3 N 4 -based direct Z-scheme based photocatalysts for energy and environmental applications.
Abstract: Solar photocatalysis is one of the most emerging feasible solutions for the prevailing energy and environmental issues in a sustainable manner. In this context, graphitic carbon nitride (g-C 3 N 4 ) is evolving as a highly appropriate and intriguing material due to its fascinating physicochemical features. Low absorption range, low specific surface area (SSA), fewer active sites, high electron-hole recombination rate, and insufficient redox potentials limits its photocatalytic performance. The widely reported strategies to address the above limitations include doping, morphological tuning, type II heterojunction, Z-scheme heterojunctions etc. Among these, in recent years, Direct Z-scheme based photocatalysts has emerged as the most promising one as it maximizes the redox potential and enables effective spatial charge separation. The widely reported g-C 3 N 4 -based direct Z-scheme systems includes g-C 3 N 4 -wide band gap SCs, g-C 3 N 4 -narrow band gap SCs and g-C 3 N 4 -based ternary composite. Keeping this in mind, the current review tries to identify the challenges and future prospects of g-C 3 N 4 -based direct Z-scheme systems for energy and environmental applications. This review reveals that the g-C 3 N 4 -narrow band gap SC system is advantages over the g-C 3 N 4 -wide band gap SC system for solar photocatalytic applications as it produces larger amount of photo-generated effective charge carriers. The review found that, ternary Z-scheme system can perform better, however minute optimization at molecular level is still required. Additionally, in depth studies on the Fermi level and associated Fermi level alignment are needed for better understanding of Z-scheme systems and for its commercialization.

12 citations

Journal ArticleDOI
TL;DR: The results of the free radical quenching experiment and electron spin resonance tests showed that h+ played a major role in the photoreaction process, followed by ˙O2- and �’OH, and a possible double Z-type reaction mechanism was proposed.
Abstract: In this work, a PCN/Fe2O3/CdS ternary heterojuction photocatalyst was constructed by introducing an appropriate amount of ferric oxide (Fe2O3) and cadmium sulfide (CdS) onto porous carbon nitride (PCN), denoted as PCN/Fe2O3/CdS. In the presence of PCN/Fe2O3/CdS, the turnover frequency value and selectivity of the oxidative coupling reaction of benzylamine were 6740 μmol g−1 h−1 and 99.4%, respectively. The excellent catalytic performance of the PCN/Fe2O3/CdS photocatalyst is attributed to fully exposed active sites due to the porous structure of PCN, improved light utilization efficiency by introduction of Fe2O3 and CdS, and increased mobility of e−–h+ pairs by construction of a ternary heterostructure, and was proved by the analysis of its structural and optical properties. According to the substrate scope study and Hammett diagram analysis, the rate determining step of the benzylamine self-coupling reaction photocatalyzed by PCN/Fe2O3/CdS was the condensation of imine and benzylamine into N-benzylidenebenzylamine. The results of the free radical quenching experiment and electron spin resonance tests showed that h+ played a major role in the photoreaction process, followed by ˙O2− and ˙OH. After four photocatalytic reaction cycles, the catalytic performance of the PCN/Fe2O3/CdS heterojunction composite material remained good. Finally, combined with the free radical trapping experiment and energy band structure analysis, a possible double Z-type reaction mechanism was proposed.

11 citations

Journal ArticleDOI
TL;DR: A defect-engineered WO3−x @MoS2 hollow tube that exhibits enhanced Fenton-like activity and improved photoactivity in a wide range of pH as a versatile platform for water purification was reported in this article .
Abstract: Here we report a defect-engineered WO3−x @MoS2 hollow tube that exhibits not only enhanced Fenton-like activity but also improved photoactivity in a wide range of pH as a versatile platform for water purification. Its successful performance was achieved by tuning oxygen defect and band position and investigated using tetracycline degradation and E. coli inactivation experiments as concept demonstration. The activity of WO3−x @MoS2 can reach one to two orders of magnitude higher than that of other materials used in this work and the ecotoxicity of intermediates was largely reduced. It exhibits an intrinsic radical character for H2O2 decomposition under dark condition and an efficient photon utilization under visible light irradiation, which is clearly different from the conventional photocatalysts and Fenton reagents. The present strategy of combing the dark Fenton-like and photocatalytic activities extends the applications of the conventional photocatalysts and should be an efficient way of energy utilization.

11 citations