Synergy in magnetic Ni_(x)Co_(1)O_(y) oxides enables base-free selective oxidation of 5-hydroxymethylfurfural on loaded Au nanoparticles

The base-free aerobic oxidation of 5-hydroxymethylfurfural(HMF) to 2,5-furandicarboxylic acid(FDCA)in water is recognized as an important and sustainable upgrading process for cellulosic carbohydrates.However,selectivity control still remains a challenge.Here,we disclose that the unique synergy in magnetic Ni_(x)Co_(1)O_(y)(x=1,3 and 5) bimetallic oxides can induce reactive oxygen defects and simultaneously stabilize small-sized metallic Au nanoparticles in the Au/Ni_(x)Co_(1)O_(y)catalysts.Such catalytic features render effective adsorption and activation of O_(2),OH and C=O groups,realizing selective oxidation of HMF to FDCA.On a series of magnetic Au/Ni_(x)Co_(1)O_(y)catalysts with almost identical Au loadings(ca.0.5 wt%) and particle sizes(ca.2.7 nm),the variable Ni/Co molar ratios give rise to the tunable electron density of Au sites and synergistic effect between NiO and CoO_(y).The initial conversion rates of HMF and its derived intermediates(i.e., DFF,HMFCA and FFCA) show a volcano-like dependence on the number of oxygen defects(i.e.,O_(2)^(-)and O^(-)) and electron-rich Au0sites.The optimum Au/Ni3Co1Oycatalyst exhibits a highest productivity of FDCA(12.5 mmol_(FDCA)mol_(Au)^(-1)h^(-1)) among all the Au catalysts in the literature and achieves> 99% yield of FDCA at 120℃ and 10 bar of O_(2).In addition,this catalyst can be easily recovered by a magnet and show superior stability and reusability during six consecutive cycling tests.This work may shed a light on Au catalysis for the base-free oxidation of biomass compounds by smartly using the synergy in bimetallic oxide carriers.

Analysis of coordinate time series of DORIS stations on Eurasian plate and the plate motion based on SSA and FFT

This study focuses on analyzing the time series of DORIS beacon stations and plate motion of the Eurasian plate by applying Singular Spectrum Analysis(SSA)and Fast Fourier Transform(FFT).First,the rend terms and periodic signals are accurately separated by SSA,then,the periodic seasonal signals are detected using SSA,and finally,the main components of the time series are reconstructed successfully.The test results show that the nonlinear trends and seasonal signals of DORIS stations are detected successfully.The periods of the seasonal signals detected are year,half-year,and 59 days,etc.The contribution rates and slopes in E,N,and U directions of the trend items of each beacon station after reconstruction are obtained by least-square fitting.The velocities of these stations are compared with those provided by the GEODVEL2010 model,and it is found that they are in good agreement except the DIOB,MANB,and PDMB stations.Based on the DORIS coordinate time series,the velocity field on the Eurasian plate is constructed,and the test shows that the Eurasian plate moves eastward as a whole with an average velocity of 24.19±0.11 mm/y in the horizontal direction,and the average velocity of it is1.74±0.07 mm/y in the vertical direction.

Performant Au hydrogenation catalyst cooperated with Cu-doped Al_(2)O_(3) for selective conversion of furfural to furfuryl alcohol at ambient pressure

Catalytic hydrogenation of furfural to furfuryl alcohol is an important upgrading process for valorization of biomass-derived furanyl platform molecules.However,selective hydrogenation of a,b-unsaturated aldehydes like furfural to the corresponding alcohols at ambient pressure remains challenging in sustainable chemistry.Till date heterogeneous Au hydrogenation catalyst has been scarcely reported for this reaction due to the low reactivity of Au for H_(2)dissociation.In this work,we showed that Au nanoparticles(loading:0.2 wt%)with a mean size of about 3 nm supported on Cu-doped Al_(2)O_(3)can efficiently hydrogenate furfural to furfuryl alcohol in liquid phase at ambient pressure.We demonstrated that doping a small amount of Cu(2 mol%)to g-Al_(2)O_(3)may modify the Lewis acidity-basicity of Al_(2)O_(3)and simultaneously induce the presence of sufficient Cu^(+) species on surface,which facilitated the hydrogen transfer from i-PrOH to furfural.Moreover,we observed an enhanced reactivity of Au toward molecular H_(2)via cooperation with the Lewis acidic-basic Cu_(2)O-Al_(2)O_(3)support.Hence,100%yield to furfuryl alcohol with a productivity of 0.98 g_(FA),h^(-1),g^(-1)_(cat.)at 120C and 0.1 MPa H_(2)can be obtained.The prepared Au/Cu-Al_(2)O_(3)catalyst was found reusable and was effective to the concentrated furfural solution,as well as several typical unsaturated aldehydes.

Efficient hydrogenation of furfural to furfuryl alcohol by magnetically recoverable RuCo bimetallic catalyst

A magnetically recoverable Ru Co bimetallic catalyst was reported for the catalytic hydrogenation of furfural to furfuryl alcohol under ambient H_(2) pressure.The magnetic catalyst was prepared by H_(2) treatment of the Ru Co composite precursor from a facile one-pot hydrolysis of Co and Ru salts by NaBH_(4) solution.This catalyst can totally convert furfural to 98–100% furfuryl alcohol at 120°C under 1 bar H_(2) in isopropanol or water using only molecular H_(2) as hydrogen source.Moreover,the catalyst showed excellent stability during recycling test and can be easily and completely recovered by magnet from reaction solution.The influence of Ru/Co ratio and H_(2)-treatment temperature was studied,which were shown to be important for the structural evolution and the metal interaction in Ru Co active sites,based on the comprehensive characterizations including XRD,TGA,TEM,XPS,H_(2)-TPR,CO adsorbed DRIFT-IR.It was demonstrated that the cooperative Ru~0–Co~0 bimetallic active sites in strong interaction can significantly promote activity and selectivity of the catalyst due to an enhanced adsorption and activation of furfural and H_(2),and simultaneously created a strong magnetism in the Ru Co catalyst for simple physical separation.

新型半固态液流储能电池研究进展

发展大规模储能技术是促进可再生能源高效利用及保证国家能源安全的关键。半固态液流电池兼具传统锂离子电池和均相液流电池的优点,拥有能量密度高、易放大、环境适应性强、功率/容量解耦等优点。半固态液流电池的电极液由固体活性颗粒和液态电解液构成,导致其循环稳定性差。本文将分析典型半固态液流电池储能技术的研究进展、面临的挑战,并就其未来发展趋势进行展望。