查看更多>>摘要：NiFe(oxy)hydroxide(NiFeOOH)is recognized as a highly active non-precious metal catalyst in alkaline water electrolysis due to its exceptional catalytic properties.In this work,high valence molybdenum(Mo)is introduced to improve the electronic structure and enhance the electrical conductivity of NiFeOOH for oxygen evolution reaction(OER).The introduction of Mo results in a Mo-doped NiFeOOH catalyst with a significantly reduced overpotential of 205 mV at 10 mA/cm2 and a Tafel slope of 31.7 mV/dec,enabling stable operation for up to 170 h.Both empirical experiment and theory simulations are employed to gain insight into the 3d-electron interactions between molybdenum and nickel(Ni),iron(Fe)in Mo-doped NiFeOOH.The results indicate that Mo-doping enhances the valence states of Ni and Fe,leading to a shift in the d-band center of the bimetallic active sites.This modification affects the transformation of Mo-doped NiFeOOH into the y-NiFeOOH active phase.This potent combination lends credence to its potential suitability and utility in OER applications.
查看更多>>摘要：Mesoporous biochar(MC)derived from biomass is synthesized using a dual-salt template method involving ZnCl2 and KC1,followed by impregnation with polyethyleneimine(PEI)of varying average molecular weights under vacuum conditions to construct a core-membrane structure for enhancing carbon capture performance.The resulting MC exhibits a highly intricate network of micropores and abundant mesopores,along with defects in graphitic structures,effectively facilitating robust PEI loading.Among the PEI-modified samples,PEI-600@MC demonstrates the highest CO2 sorption capacity,achieving approximately 3.35 mmol/g at 0.1 MPa and 70℃,with an amine efficiency of 0.32 mmol CO2/mmol N.The introduction of amine functional groups in PEI significantly enhances the sorption capacity compared to bare MC.Additionally,PEI with lower average molecular weights exhibits a superior sorption performance at low pressures but shows a reduced thermal stability compared to higher molecular weight counterparts.The area of sorption hysteresis loops gradually decreases with increasing temperature and average molecular weight of PEI.The equilibrium sorption isotherms are accurately modeled by the Langmuir equation,revealing a maximum sorption capacity of approximately 3.53 mmol/g at 70℃ and saturation pressure.This work highlights the potential of dual-salts templated biomass-derived MC,modified with PEI,as an effective,widely available,and cost-efficient material for CO2 capture.
查看更多>>摘要：Ammonia is an exceptional fuel for solid oxide fuel cells(SOFCs),because of the high content of hydrogen and the advantages of carbon neutrality.However,the challenge lies in its unsatisfactory performance at intermediate temperatures(500-600℃),impeding its advancement.An electrolyte-supported proton-ceramic fuel cell(PCFC)was fabricated employing BaZr0.1Ce0.7Y0.2O3-δ(BZCY)as the electrolyte and Ba0.5Sr0.5Co0.8Fe0.2O3-δ(BSCF)as the cathode.In this study,the performance of PCFC using NH3 as fuel within an operating temperature range of 500-700℃ was improved by adding an M(Ni,Ru)/CeO2 catalyst layer to reconstruct the anode surface.The electrochemical performance of direct ammonia PCFC(DA-PCFC)were improved to different extents.Compared to H2 as fuel,the degradation ratio of peak power densities(PPDs)of Ni/CeO2-loaded PCFC fueled with NH3 decreased at 700-500℃,with a decrease to 13.3％at 700℃ and 30.7％at 500℃.The findings indicate that Ru-based catalysts have a greater promise for direct ammonia SOFCs(DA-SOFCs)at operating temperatures below 600℃.However,the enhancement effect becomes less significant above 600℃ when compared to Ni-based catalysts.
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