查看更多>>摘要：Thermal and solar energies are two pivotal components in photothermal catalysis, however, their synergistic energy efficiency for a maximum yield is more important but less investigated. Herein, systematic studies unveil the promotion effects of external heat on the excitation and utilization of energetic hot carriers (EHC) on Pt/TiO2 in photothermal catalysis. Onset reaction temperature of a reaction is found to be the key in control of the energy synergy. When the minimum onset reaction temperature of uphill processes is exceeded, a smaller number of active sites on the catalyst are available to EHC, resulting in a suppressed thermal effect. Rational regulation of EHC and thermal energy in photothermal catalysis leads to optimum quantum efficiencies of both dry reforming of methane and reverse water-gas shift reactions at a medium level of temperature. This work provides new insights to balance thermal and solar-driven catalysis to better conduct photothermal catalysis for fossil fuels upgrading.
查看更多>>摘要：Reductive amination of furfural (1a) to furfurylamine (2a) was developed as a powerful and practical approach to biomass-based amine. Herein, Ru catalyst (Ru/BNC) supported on boron/nitrogen co-doped carbon (BNC) was reported for the reductive amination with hydrous hydrazine (N2H4 center dot H2O) as a nitrogen source and hydrazone as intermediate. Our mechanism investigation suggested rich Frustrated Lewis acid-base pairs (FLPs) on the BNC surface synergistically enhanced the activity of Ru catalyst. Moreover, quick formation rate of hydrazone intermediate and its moderate reactivity significantly improved 2a selectivity. Under optimal conditions, Ru/BNC catalyst can highly efficiently and selectively promote 1a/N2H4-to-2a transformation with 2a yield exceeding 99%. Moreover, the role of nitrogen sources such as N2H4, NH3 and hydroxylamine on the 2a selectivity was systematically investigated. Additionally, the developed Ru/BNC-N2H4 system was applicable to a wide range of aldehydes to give the desired primary amines in excellent to good yields (85-99%) in the reductive amination reaction.
查看更多>>摘要：Efficient removal of human-emitted gaseous pollutants in indoor air may greatly reduce ventilation-related energy consumption, however few efforts have been made. Here we reported the room and low-temperature catalytic removal of a human-emitted odorant -acetic acid with odor threshold of 5.6 ppb. Ultrathin delta-MnO2 nanoribbons (delta-MnO2 UTNRs) with the thickness of 1-1.5 nm and aspect ratio of 200-600 was synthesized, which produced abundant active oxygen species such as hydroxyl radicals and superoxide at room temperature without light irradiation. Accordingly, as-prepared delta-MnO2 UTNRs could transform acetic acid into CO2 even at room temperature. The 100% one-through removal capacity for ~1 ppm acetic acid was about 20 mg/g, and it could be completely regenerated at 14 & nbsp;C-0. This study opens a new research direction and demonstrates that it is possible to catalytically remove human-emitted gaseous pollutant at low and even at room temperature.
Kim, Young KyeongLee, Tack HoYeop, JiwooByun, Woo Jin...
9页
查看更多>>摘要：A hetero-tandem organic photovoltaic (OPV) device consisting of large (PM6:IT-M) and small-bandgap (PM6:Y6) bulk-heterojunctions is developed to provide an open-circuit voltage of 1.84 V and a power-conversion-efficiency of 11.7%, which could serve as an ideal light absorber to drive water electrolysis. The fabricated OPV is combined with an electrolyzer composed of NiFeOx(OH)y and Pt electrocatalysts to demonstrate a photovoltaic electrolysis (PV-EC) system. Furthermore, the system is designed to locate the operating voltage of the OPVEC system at the maximum power point of OPV to minimize power loss. As a result, our hetero-tandem OPVEC device achieves the highest solar-to-hydrogen conversion efficiency among OPV-based systems, (up to 10%), which represents a new benchmark for OPV-based solar fuel production. Finally, a wireless monolithic organic artificial leaf is constructed for the first time, which demonstrates a stable solar hydrogen production in water.
查看更多>>摘要：The most crucial factors limiting the degradation performance of photoelectrocatalytic (PEC) process are the low charge separation efficiency and slow mass transportation. Herein, we report a WO3 network photoelectrode by constructing heterophase junction of WO3 on tungsten mesh (hm-m-WO3/W mesh), which exhibits superior PEC performance, as high as 5.6 mA cm(-2) of photocurrent density at 1.2 V-RHE, achieving a complete degradation (99.9%) and nearly total mineralization (84.5%) of bisphenol A, reaching an apparent reaction rate constant of 5.7 x 10(-2) min(-1), 1.5 times of WO3 based photoelectrode ever reported. A Schottky junction is formed at m-WO3/W interface which greatly promotes the charge transfer between catalysts and support. The catalysts show appropriate phase alignment, where the parallel directions between built-in electric field of heterophase junction and external potential benefit charge separation. Computational fluid dynamics simulations indicate the network structure favors the diffusion of the fluid containing pollutants. This work demonstrates a viable strategy for designing the photoelectrode with high charge separation efficiency and fast mass transportation in PEC wastewater treatment.
查看更多>>摘要：In this work, MoS2 is utilized as a cocatalyst to enhance Fe3+/PMS reaction for the deep oxidation of aromatic VOCs in a continuous air-bubbling system. The exposed Mo4+ active sites achieve high-speed electron transfer from MoS2 (001) surface to Fe3+ and accelerate Fe2+ regeneration (~60%), which greatly promotes O2 and PMS activation for the formation of radicals like O-2(center dot-), HO center dot and SO4 center dot-. Consequently, the Fe3+/PMS/MoS2 system exhibits strong catalytic ability for various VOCs degradation including styrene, toluene and chlorobenzene (with removal efficiency of 97%, 84% and 83%, respectively) at a wide pH range (3-9). MoS2 cocatalyst in Fe3+/PMS reaction greatly promotes the activation of O-2 into radicals and inhibits the formation of toxic aromatic byproducts via the deep oxidation of styrene into CO2. Our study provides a green strategy to activate O-2 for pollutants degradation and has great potential to be widely applied in actual environment remediation.
查看更多>>摘要：Iron-nitrogen-carbon (Fe-N-C) catalysts for oxygen reduction reaction (ORR) are promising candidates in fuel cell devices but the poor stability remains a grave challenge. The elimination of demetallation is pivotal for extending the life but still incapable due to the ambiguous mechanism. Herein, we show that the structure of FeN4 site and its structural evolution during ORR has the significant influence. The end-of-test/in-situ Mossbauer spectroscopy and density functional theory study reveal that D1 mainly contributes to the ORR activity but suffers severe demetallation, which is likely due to the instability of FeN4C8. The faster demetallation during ORR, especially at higher potential, can be attributed to the weaker coordination of FeN4 induced by oxygenated intermediate and electric field according to ab initio molecular dynamics simulations. Finally, the binding energy of Fe-N bond is introduced to describe the influence of structure and structural evolution and give guidance to the improvement of stability.
查看更多>>摘要：Selective oxidation of 5-hydroxymethylfurfural (HMF) to 5-formyl-2-furancarboxylic acid (FFCA) is a critical reaction for producing value-added chemicals from biomass. The challenge for this reaction is to develop an efficient catalytic process that can be conducted under mild conditions. Herein, we first propose piezocatalytic HMF oxidation using a Pt decorated hydroxyapatite (HAP) piezocatalyst (Pt/HAP). The introduction of Pt on HAP creates an interfacial electric field. The couple of nonlocal piezoelectric field and localized interfacial electric field greatly promotes both the bulk and surface charges transfer. Moreover, Pt not only promotes the separation of piezo-induced charges but also activates oxygen molecules and organic functional groups of the substrates. Compared with pristine HAP, Pt/HAP exhibits outstanding piezocatalytic activity, which reached 96% HMF conversion and 70% FFCA yield in 2 h under room temperature. A wide range of aldehydes and alcohols, such as fatty aldehydes, furan aldehydes, fatty alcohols, and ethylene glycol, were all oxidized to carboxylic acids. This work provides a novel method on utilizing piezocatalysis for biomass conversion.
查看更多>>摘要：High metal loading of single-atom catalysts enables excellent catalytic activity, but possibly causes serious aggregation problem. Herein, a series of diatomic FeCo-N/C-x (x represents metal content) were skillfully designed and applied to improve the catalytic activity for peroxymonosulfate (PMS) activation toward degrading organic micropollutants. The unprecedented dual active sites, referring to Fe(N-3)-Co(N-3) moiety and FeCo alloy, are constructed on the obtained FeCo-N/C-x, thereby exhibiting significantly greater performance toward degrading aqueous phenol (e.g., 0.316 min(-1) for FeCo-N/C-3) via PMS activation, compared with those of traditional single-atom Co-N/C (0.011 min(-1)) and Fe-N/C (0.018 min(-1)). Combined experimental and theoretical calculations demonstrate the independent functions of dual active sites, in which Fe(N-3)-Co(N-3) and FeCo alloy can decrease the energy barrier of O-O bond cleaving resulting in the formation of high-valent FeCo=O reactive species and singlet oxygen, respectively. This study opens up a new platform toward constructing dual active sites for enhanced Fenton-like catalytic activity.
查看更多>>摘要：Catalytic oxidation is one of the most promising methods to remove VOCs. Herein, a zeolite-confined PtMn bimetal catalyst (PtMn0.2 @ZSM5) was synthesized using a ligand-assisted hydrothermal method, which showed extraordinary catalytic activity with a T-95 of 165 degrees C for the acetone oxidation in the presence of 5 vol% water. Thanks to the zeolite confinement and bimetallic synergy effect, the PtMn0.2 @ZSM5 exhibited small nano-particle sizes, abundant acid sites, higher active Pt-0 content, and sufficient active oxygen species. These excellent properties promoted the adsorption of VOC, the deep oxidation of VOC, and the desorption of CO2. In-situ DRIFTS proposed an L-H mechanism for acetone oxidation over PtMn0.2 @ZSM5. Significantly, the PtMn0.2 @ZSM5 presented good durability and water resistance under high GHSV conditions. Also, it was confirmed effective for various VOCs oxidation, such as toluene, ethyl acetate, propane, and dichloromethane, showing a promising industrial prospect for eliminating VOCs.
NSTL
Elsevier