The Cu(I)-catalyzed pentafluoroethylation of iodoarenes via the fluorocupration of tetrafluoroethylene (TFE) is disclosed. The active species, (phen)CuC₂F₅, was isolated and its molecular structure ...confirmed by a single-crystal X-ray diffraction analysis. The key to the successful suppression of the competing oligomerization of TFE is to refrain from stirring the reaction mixture. A mechanistic study clearly discarded the possibility that the catalytic reaction proceeds via a radical pathway.
•Comparison of different advanced oxidation processes for multi-air-pollutant removal is reviewed.•Catalytic reaction mechanism of NO and the mechanism of different metal elements doping catalysts ...are summarized.•The industrialization prospects and challenges and suggestions for industrial operation is provided.
Integrated pollutant removal technology has gradually become a research focus due to its simple layout and low operating cost. The research and development of this technology does not only benefit the operation of coal-fired power plants but also provide an idea for the removal of pollutants from numerous industrial boilers. In this paper, the recent development of mainstream advanced oxidation-integrated gas removal technology, which includes non-thermal plasma, chlorine-based, sulfur-based, ozone oxidation absorption, and Fenton-based methods, was comprehensively reviewed. The advantages and disadvantages of these methods were illustrated, and the superiority of the application prospects of Fenton-based methods was clarified. Then, two studies focusing on multi-air-pollutant removal mechanism during Fenton-based processes were discussed in detail, including the catalytic reaction mechanism of NO and the catalytic mechanism of different metal-element doping catalysts. The mechanisms of different doping metal elements were classified into four aspects: (1) redox pairing formed by transition metals; (2) induction of photocatalytic reaction to generate conduction band electrons; (3) formation of electrochemical corrosion units; and (4) optimization of the physical and chemical characteristics of the catalyst to promote H2O2 adsorption and dissociation. The industrialization prospects were systematically analyzed, and the operation cost only accounted for 20% of the traditional wet flue gas desulfurization and selective catalytic reduction removal system. Meanwhile, two feasibility Fenton-based industrial design ideas were proposed. The challenges and suggestions on oxidants, catalysts, and economic operation for future application were analyzed, thus providing inspirations for multi-air-pollutant removal.
Highly efficient photocatalytic hydrogen evolution (PHE) is highly desirable for addressing the global energy crisis and environmental problems. Although much attention has been given to ...electron–hole separation, ridding photocatalysts of poor efficiency remains challenging. Here, a two‐electron catalytic reaction is developed by utilizing the distinct trion behavior of ReS2 and the efficient reduction of two H+ (2H+ + 2e− → H2) is realized. Due to the monolayer‐like structure of the catalyst, the free electrons in ReS2 can be captured by the tightly bound excitons to form trions consisting of two electrons and one hole. These trions can migrate to the surface and participate in the two‐electron reaction at the abundant active sites. As expected, such a two‐electron catalytic reaction endows ReS2 with a PHE rate of 13 mmol g−1 h−1 under visible light irradiation. Meanwhile, this reaction allows the typically poor PHE efficiency of pure transition metal dichalcogenides to be overcome. The proposed two‐electron catalytic reaction provides a new approach to the design of photocatalysts for PHE.
A two‐electron catalytic reaction is first demonstrated by utilizing the trions in ReS2 and a superior photocatalytic hydrogen evolution rate of 13 mmol g−1 h−1 is achieved, which surpasses the rates of most reported transition metal dichalcogenide composite photocatalysts. This work sheds light on the two‐electron catalytic reaction of photogenerated excitons in semiconductors, providing a new approach to the design of highly efficient photocatalysts.
The active sites on oxygen electrocatalyst and the number of inherent active species are important factors affecting the performance of Zn-air battery. Constructing multiphase interfaces is an ...effective strategy to increase the number of active species for oxygen electrocatalysts. In this work, the number of intrinsic active species of spinel oxygen electrocatalyst was increased and its catalytic activity was enhanced by the synergistic action of bimetallic center three interfaces and heteroatom-doped carbon nanostructures. The resulting NiCo2O4/NCNTs/NiCo as catalyst exhibits superior activity toward ORR (E1/2 = 0.83 V, JL = −5.38 mA cm−2) and OER (Ej10 = 1.58 V). Further, the obtained catalyst work as a cathode assembles as Zn-air battery with a high open-circuit potential of 1.51 V and excellent cycle stability (586 h). Theoretical results indicate that the desorption of *OH species is the rate-determining step for ORR, the multiphase interfaces in the NiCo2O4/NCNTs/NiCo will provide additional electrons due to the upward shift of antibonding orbitals relative to the Fermi level. Consequently, it boosts the oxygen adsorption and charge transfer and accelerate the reaction kinetics. This work emphasizes the synergistic effect between multiphase interfaces in transition metal composite catalysts and opens up a promising way for the preparation of efficient and stable transition metal electrocatalysts.
•A unique triphasic interfacial structure catalyst has been synthesized by a simple strategy.•The ultra-thin carbon layer catalyzed by NiCo alloy facilitates interfacial charge transfer.•The obtained catalyst exhibits excellent oxygen catalytic performance for zinc-air battery.
Owing to the shuttle effect of lithium polysulfides (LiPSs), poor conductivity and low loading mass of active sulfur, and its large volume expansion during cycling, these shortcomings still restrict ...practical application of high performance lithium-sulfur (Li-S) batteries. Herein, a stable flexible current collector, composed of ultralong MnO2 nanowires and expanded graphite nanosheets (MnO2 NW/EG) with high electronic conductivity, is combined with Li2S6 to serve as a self-supporting cathode in Li-S batteries, in which the maximum loading mass of sulfur can be regulated to 7 mg cm−2, the ultralong MnO2 nanowires has the ability to accelerate the adsorption and catalytic conversion of LiPSs through the chemical action of the polar active surface and the good mechanical flexibility caused by the introduction of ultralong nanowires and nanosheets can buffer the large volume expansion of sulfur during charging/discharging. Moreover, Li-S batteries with MnO2 NW/EG current collector still maintain a high capacity of 538 mAh g−1 after 500 cycles at 1 C and the capacity decay is only 1.2 mAh g−1 per cycle, even when the sulfur loading is 7 mg cm−2, the capacity can be as high as 2.5 mAh cm−2, indicating a practical application ability.
Display omitted
•A stable flexible current collector is applied in Li-S batteries.•The loading mass of sulfur can be regulated to 7 mg cm−2•The MnO2 nanowires can accelerate the adsorption and catalytic conversion of LiPSs.•The cathode with high sulfur loading mass exhibits excellent cyclic stability.
Display omitted
•Fe-N-C catalyst (FexMny-Fe@NCs) was consisted of FeN4 coordination.•Fe-N-C catalyst could activate PMS to effectively degrade 4-aminobenzoic acid ethyl ester (ABEE).•Pyrrolic N ...served as adsorption site as well as singlet oxygen generation site.•Fe-pyridinic N-C acted as hydroxyl radical and sulfate radical generation site.•Singlet oxygen and superoxide radical dominated the catalytic reaction.
Understanding the origin of high activity of graphene layers encapsulated Fe-N-C catalysts in Fenton-like reaction is critical, but still challenging for developing catalysts with high activity and durability. Therefore, we prepared a highly active Fe-N-C catalyst (FexMny-Fe@NCs) containing FeN4 coordination to activate peroxymonosulfate (PMS) toward 4-aminobenzoic acid ethyl ester (ABEE) degradation, and revealed the multiple catalytic reaction sites by investigating the composition and the structure of the catalyst. The relationship between the catalytic degradation performance and multiple catalytic reaction sites was performed on the basis of both experiments and density functional theory (DFT) calculations. The catalytic performance of Fe2Mn1-Fe@NCs was found to show optimal catalytic degradation performance. Pyrrolic N served as adsorption site as well as singlet oxygen generation site to promote the catalytic degradation. Fe-pyridinic N-C acted as hydroxyl radical and sulfate radical generation site. Both singlet oxygen and superoxide radical were dominated the catalytic reaction. The insight achieved from this study may be further applied to other Fe-N-C catalysts design and further efficient organic pollution remediation.
The emulsions stabilized by solid particles, Pickering emulsion, have excellent stability and are environmentally friendly compared to the emulsions stabilized by surfactants upon most occasions. The ...physical–chemical properties of emulsion system, such as stimuli responsive, controllable release and mechanical strength can be precisely tuned through the particle properties and preparation process. This review has carried on the target-oriented summary about the recent progress and applications of multiple Pickering emulsions. The unique superiority of Pickering stabilization at liquid–liquid interface is discussed. The particle wettability has been proved to play an important role in emulsions formation and stabilization. How to prepare multiple Pickering emulsions successfully are described based on emulsification process and novel technologies. And the influence of particles on the multiple emulsion properties are analyzed. In addition, we present the applications of multiple emulsions in material preparation, such as microspheres and microcapsules, and its application for reaction process is prospected.
We synthesized a series of carbon‐supported atomic metal‐N‐C catalysts (M‐SACs: M=Mn, Fe, Co, Ni, Cu) with similar structural and physicochemical properties to uncover their catalytic activity trends ...and mechanisms. The peroxymonosulfate (PMS) catalytic activity trends are Fe‐SAC>Co‐SAC>Mn‐SAC>Ni‐SAC>Cu‐SAC, and Fe‐SAC displays the best single‐site kinetic value (1.65×105 min−1 mol−1) compared to the other metal‐N‐C species. First‐principles calculations indicate that the most reasonable reaction pathway for 1O2 production is PMS→OH*→O*→1O2; M‐SACs that exhibit moderate and near‐average Gibbs free energies in each reaction step have a better catalytic activity, which is the key for the outstanding performance of Fe‐SACs. This study gives the atomic‐scale understanding of fundamental catalytic trends and mechanisms of PMS‐assisted reactive oxygen species production via M‐SACs, thus providing guidance for developing M‐SACs for catalytic organic pollutant degradation.
A series of carbon‐supported atomic metal‐N‐C catalysts with similar structural and physicochemical properties were synthesized to uncover the activity trends and mechanisms in peroxymonosulfate‐assisted reactive oxygen species production. Fe‐SAC displays the best single‐site kinetic value (1.65×105 min−1 mol−1), and the PMS→OH*→O*→1O2 is the most reasonable 1O2 reaction pathway.
Green synthesis of nanoparticles using plant extracts minimizes the usage of toxic chemicals or energy. Here, we concentrate on the green synthesis of nanoparticles using natural compounds from plant ...extracts and their applications in catalysis, water treatment and agriculture. Polyphenols, flavonoid, rutin, quercetin, myricetin, kaempferol, coumarin, and gallic acid in the plant extracts engage in the reduction and stabilization of green nanoparticles. Ten types of nanoparticles involving Ag, Au, Cu, Pt, CuO, ZnO, MgO, TiO2, Fe3O4, and ZrO2 with emphasis on their formation mechanism are illuminated. We find that green nanoparticles serve as excellent, and recyclable catalysts for reduction of nitrophenols and synthesis of organic compounds with high yields of 83–100% and at least 5 recycles. Many emerging pollutants such as synthetic dyes, antibiotics, heavy metal and oils are effectively mitigated (90–100%) using green nanoparticles. In agriculture, green nanoparticles efficiently immobilize toxic compounds in soil. They are also sufficient nanopesticides to kill harmful larvae, and nanoinsecticides against dangerous vectors of pathogens. As potential nanofertilizers and nanoagrochemicals, green nanoparticles will open a revolution in green agriculture for sustainable development.
Display omitted
•Plant-mediated synthesis of ten types of green nanoparticles was overviewed.•Effect of synthesis parameters on morphology and particle size was discussed.•Green nanoparticles exhibited good catalytic activities and adsorption performance.•Nanoparticles acted as green pesticides, fertilizers, and agrochemicals in agriculture.
•The formation of Co-N bond in hybrid catalyst can effectively enhance interfacial charge transfer.•Enhanced oxygen catalytic activity using NCNTs/Ni offers excellent electrical conductivity.•The ...CoSx/NCNTs/Ni exhibits outstanding ORR/OER performance and realizes the potential for application on zinc-air batteries.
The slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remain the primary problem impeding the commercialization of zinc-air batteries (ZABs). Herein, we demonstrate a hybrid composite consisting of multivalent CoSx nanoparticles and nitrogen-doped carbon nanotubes catalytically active-nickel (NCNTs/Ni) as an advanced ORR/OER electrocatalyst with excellent electrocatalytic activity. The Co-N bonds in the hybrid catalyst effectively enhance interfacial charge transfer, resulting in synergetic effects for enhanced oxygen electrochemistry. The optimized hybrid, CoSx/NCNTs/Ni-2, affords excellent performance in an alkaline ZAB, achieving a high-power density of 131 mW cm−2, and the voltage gap remained at only 0.87 V after 200 h of continuous charge–discharge at 5 mA cm−2. This study provides a facile strategy for the construction of bifunctional hybrids with non-precious metals for potential application in ZABs and other sustainable energy conversion devices.
