查看更多>>摘要：In this study,N and O co-doping carbon materials with porous structure(NOPC-x)were applied to activate peroxymonosulfate(PMS)for bisphenol(BPA)degradation and the underlying effects in affecting NOPC-x activity were revealed.Electrochemical characterization,electron paramagnetic resonance(EPR)tests,quenching and PMS adsorption experiments were applied to clarify the mechanism of BPA degradation.It's found that BPA can be completely removed within 20 min(k_(obs)= 0.30 min~(-1))in the NOPC/PMS system depending on the electron transfer path with the necessity of moderate surfaced unpaired electrons for electrons delivery,which could be regulated by the modifier dosage.However,excessive surfaced unpaired electrons were unfavorable to PMS adsorption,resulting in deterioration of BPA degradation.This study indicates that controlling the amount of surfaced unpaired electrons in an appropriate range is essential to ensure the carbonaceous materials activity in PMS activation to obtain a satisfactory BPA degradation.
查看更多>>摘要：Direct oxidative conversion of methane(CH4)into useful C1 products remains challenging due to the low reactivity of CH4 and its facile overoxidation into carbon dioxide(CO2)under high temperature conditions.Iron oxide(FeOx)cluster catalysts are promising because of their low activation energy for CH4 oxidation.However,preliminary results revealed that FeOx clusters were easily aggregated and deactivated under CH4 oxidation conditions at 873 K.In this study,we used a diiron-introduced polyoxometalate as a precursor to form thermally stable FeOx subnanoclusters on SiO2,which selectively converted CH4 into formaldehyde(HCHO)and carbon monoxide(CO)(CH4 conversion,2.3%; HCHO and CO selectivity,87% at 873 K after 1 h).The FeOx sub-nanocluster catalyst maintained catalytic activity even after 72 h.Various characterizations,such as STEM,X-ray absorption spectroscopy,and X-ray diffraction,revealed that the in situ formed FeOx subnanoclusters were stabilized by WOx nanoclusters originating from the polyoxometalate frameworks.
查看更多>>摘要：The electrochemical reduction of CO2 to methanol is a potentially cost-effective strategy to reduce the concentration of this greenhouse gas while at the same time producing a value-added chemical.Herein,we detail a highly efficient 2D nickel organic framework containing a large density of highly dispersed salophen NiN2O2 active sites toward electrochemical CO2RR to methanol.By tuning the ligand environment of the salophen NiN2O2,the electrocatalytic activity of the material toward CO2 reduction can be significantly improved.We prove that by introducing a carbonyl group at the ligand environment of the Ni active sites,the electrochemical CO2 reduction activity is highly promoted and its product selectivity reaches a Faradaic efficiency of 27% toward the production of methanol at-0.9 V vs RHE.The salophen-based π-d conjugated metal-organic framework presented here thus provides the best performance toward CO2 reduction to methanol among the previously developed nickel-based electrocatalysts.
查看更多>>摘要：The efficient electrocatalysts for hydrogen evolution reaction(HER)are indispensable.Herein,Mo2C micropillars decorated with Pt nanoparticles(<4 nm)on Mo foil(Pt/Mo2C-L/Mo)are synthesized by laser ablation in a focused mode in CH4 atmosphere and laser-induced reduction in an under-focused mode in Ar/H2 atmosphere.The Pt/Mo2C-L/Mo possesses excellent HER performance(21 mV at 10 mA cm~(-2))and stability(1317 mA cm~(-2)for 100 h)in acid media.Integrated gas diffusion and catalytic electrodes of Pt/Mo2C-L/Mo are constructed by laser in a mixed model and used in proton exchange membrane water electrolyzer(PEMWE).The voltage of the constructed PEMWE of(-)Pt/Mo2C-L/Mo || IrO2/Ti(+)(1.55 V at 10 mA cm~(-2))is lower than that of(-)20 wt.% Pt/C || IrO2(+)(1.69 V at 10 mA cm~(-2))for overall water splitting.This work provides a universal laser synthetic strategy of integrated electrodes with promising application in the field of hydrogen energy.
查看更多>>摘要：In this work,we report a novel and highly efficient catalytic membrane(PES/PNM-Ag)comprising well-dispersed silver nanoparticles(NPs).The membrane can be straightforwardly constructed via dynamic loading expansible hybrid microgels PNM-Ag into a commercially-available poly(ether sulfone)(PES)membrane with asymmetric structure.Characterization results of PNM-Ag and PES/PNM-Ag indicate that a nanoscale three-dimensional network embedded with Ag NPs was developed in membrane pores by swollen microgels.The flat-sheet membrane reactor assembled with PES/PNM-Ag can efficiently and continuously catalyze the reduction of 4-nitrophenol(apparent reaction rate constant reaching 1.12 s~(-1))and showed good stability.The improved catalytic activity was attributed to fully accessible surface of Ag NPs as well as the unique structure of the membrane,in which the reactant was restricted to flow through immobilized catalyst.Present strategy hints to design other noble metal NPs loaded catalytic membranes for efficient conversion of nitro-aromatic pollutants.
查看更多>>摘要：The synthesis of intermetallic compounds with small size and defective structures is rigorous challenge.In this work,the small size(<10 nm)of intermetallic PdM(M = Pb,Sn,In)with ordered vacancies(OVs)are successfully prepared by ultrafast and solvent-free microwave method for the first time.With the optimized vacancies,atomic arrangement and components,the intermetallic OVs-Pd3Pb-2 shows the best nitrogen reduction(NRR)performance among intermetallic OVs-PdM(M = Sn,In),intermetallic OVs-Pd3Pb with various degrees of vacancies,intermetallic Pd3Pb with vacancies-free,Pd3Pb/CNT and Pd/CNT in Li2SO4 solution.In situ Raman spectroscopy,in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy(ATR-SEI-RAS)technique and density functional theory(DFT)further demonstrate the synergy mechanism of good NRR activity at low overpotentials on OVs-Pd3Pb-2 catalysts.
查看更多>>摘要：A one-pot cascade conversion of cellulose to GVL was investigated over bimetallic Ru-Cu deposited on a zeolite Y(Ru-Cu/Z)catalyst.Under supercritical methanol conditions,high-yield(49.8%)cascade conversion of cellulose to GVL was achieved at 250 ℃,with an initial H2 pressure of 3.0 MPa and reaction time of 5 h.The Ru-Cu/Z catalyst was synthesized using activated reductive deposition CARD),which resulted in the selective deposition of Cu nanodomains on Ru nanoparticles,thereby facilitating the dissociative adsorption of H2.In addition,Lewis and Br0nsted acid sites of Cu-doped zeolite Y effectively proceeded to cascade conversion reactions,including alcoholysis,isomerization,dehydration,and acetalization reactions,suppressing humin formation.The bimetallic Ru-Cu/Z catalyst was used in six consecutive runs,with a marginal loss of activity.The structure-performance relationships of the Ru-Cu/Z catalysts synthesized using ARD,incipient wet impregnation,and reduction deposition methods were compared.
查看更多>>摘要：Achieving photoreduction uranium with D-A type conjugated microporous polymers in strongly acidic radioactive wastewater holds great promise but is extremely challenging,as it requires proper electron transport channels.Herein,a redox-active perylene-anthraquinone D-A conjugated microporous polymer photocatalyst(ECUT-AQ)which electron-rich perylene unit as donor and electron-deficient anthraquinone(AQ)as acceptor is innovatively reported.The results clearly demonstrates that AQ with dual characteristics of electron deficiency and redox activity plays a key role in photocatalytic reduction of UO_2~(2+)to UO2.On one hand,the constructed D-A structure induces the formation of a huge built-in electric field,which enhances the intramolecular charge transfer,thus significantly broadening visible light absorption range and improving electron-hole pairs separation efficiency.On the other hand,and very significantly,the redox-active AQ acts as a matched electron transfer channel,which further accelerates the photogenerated electrons transfer from the photocatalyst to the UO_2~(2+).Consequently,the ECUT-AQ achieves 86% photoreduction UO_2~(2+)removal within two hours irradiation and obtains an impressive reduction rate constant(k-0.015 min~(-1),pH=1 and T = 293.15 K).Encouragingly,the current work can enlighten a whole new direction for the subsequent cultivation of more practical metal-free photocatalysts for purification radioactive wastewater.
查看更多>>摘要：The C-C bond cleavage remains a main challenge for alkaline EOR(ethanol oxidation reaction).In this work,we report an efficient PdSn-TaN/C electrocatalyst to split the C-C bonds in ethanol.Structurally,a series of characterization results confirm the presence of the low-coordinated Pd sites on the PdSn-TaN/C interface.The PdSn-TaN/C catalyst exhibits very high activity(almost 26.9 times of commercial Pd/C),good durability and high selectivity to CO2(20.5%)towards alkaline EOR.Specifically,in-situ ATR-SEIRAS(Attenuated total reflection-surface enhanced infrared absorption spectroscopy)results indicate that TaN facilitates the cleavage of C-C bonds,whereas Sn promotes the further oxidation of ethanol fragments.DFT(density functional theory)calculations indicate the activation barriers of the C-H bond cleavage in CH3CH2OH,CH3CHOH,CH3CHO,CH3CO,CH2CO and the C-C bond cleavage in CH3CO,CH2CO,CHCO are reduced evidently and the removal of adsorbed CH3CO and CO becomes easier on the PdSn-TaN/C catalyst surface.
查看更多>>摘要：Herein,a hollow microtubular Fe/Mn-promoted CaO-Ca_(12)Al_(14)O_(33)bi-functional material was prepared by the bio-template method and used for H2 production from sorption enhanced water gas shift(SEWGS).The microtubular Fe/Mn-promoted CaO-Ca_(12)Al_(14)O_(33)exhibits excellent CO2 capture and H2 production performance in SEWGS/regeneration cycles.The stable hollow microtubular structure improves available adsorption and catalytic sites in Fe/Mn-promoted CaO-Ca_(12)Al_(14)O_(33)for CO2 capture and H2 production.Mn addition improves CO2 affinity capacity of the microtubular material.The Fe-Mn interaction increases redox ability of Fe~(3+)/Fe~(3+,2+),which promotes CO conversion.Moreover,the formed Ca2Fe2O5 and Ca2MnO4 both increase oxygen vacancies to promote catalytic activity of the microtubular material for WGS and its CO2 capture capacity.The CO conversions for the microtubular material with the Fe/Mn/Al/Ca molar ratio= 10/2/10/100 are 98.7% and 94.0% after 20 cycles under the mild and severe calcination conditions,respectively.The hollow microtubular bi-functional material shows good prospect for efficient H2 production from SEWGS.
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