Transformation of urea and glycerol to glycerol carbonate is an environmental friendly and economical process.Catalysts play an indispensable role in the process.Although many catalysts have been developed,the perform...Transformation of urea and glycerol to glycerol carbonate is an environmental friendly and economical process.Catalysts play an indispensable role in the process.Although many catalysts have been developed,the performance of the catalysts still cannot meet the needs of industrialization.In this paper,research progress of the homogeneous and heterogeneous catalysts of the reaction over the past 20 years were reviewed systematically.According to the types and active centers of catalysts,the catalysts were classified systematically and analyzed in detail.The typical reaction mechanisms were also summarized.The research and development direction of catalysts is made more explicit through systematic classification and mechanism analysis.The article reveals more novel catalysts have been designed and used for the reaction,such as mixed metal oxides with special structures,solid wastes and non-metallic materials.This work summarized the current state of research and prospected possible routes for design of novel catalysts.It is hoped that this review can provide some references for developing efficient catalysts.展开更多
Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corros...Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corrosion caused by the harmful chlorine.In contrast to the oxygen evolution reaction (OER)and chlorin ion oxidation reaction (ClOR),glycerol oxidation reaction (GOR) is more thermodynamically and kinetically favorable alternative.Herein,a Ru doping cobalt phosphide (Ru-CoP_(2)) is proposed as a robust bifunctional electrocatalyst for seawater electrolysis and GOR,for the concurrent productions of hydrogen and value-added formate.The in situ and ex situ characterization analyses demonstrated that Ru doping featured in the dynamic reconstruction process from Ru-CoP_(2)to Ru-CoOOH,accounting for the superior GOR performance.Further coupling GOR with hydrogen evolution was realized by employing Ru-CoP_(2)as both anode and cathode,requiring only a low voltage of 1.43 V at 100 mA cm^(-2),which was 250 m V lower than that in alkaline seawater.This work guides the design of bifunctional electrocatalysts for energy-efficient seawater electrolysis coupled with biomass resource upcycling.展开更多
Aqueous sodium-ion batteries(ASIBs)have garnered significant attention as promising candidates for large-scale energy storage applications.This interest is primarily due to their abundant resource availability,environ...Aqueous sodium-ion batteries(ASIBs)have garnered significant attention as promising candidates for large-scale energy storage applications.This interest is primarily due to their abundant resource availability,environmental friendliness,cost-effectiveness,and high safety.However,their electrochemical performance is limited by the thermodynamic properties of water molecules,resulting in inadequate cycling stability and insufficient specific energy density.To address these challenges,this study developed a hydrogen-bond enhanced urea-glycerol eutectic electrolyte(UGE)to expand the electrochemical stability window(ESW)of the electrolyte and suppress corresponding side reactions.The eutectic component disrupts the original hydrogen bonding network in water,creating a new,enhanced network that reduces the activity of free water and forms a uniform,dense passivation layer on the anode.As a result,the optimized composition of UGE exhibits a broad ESW of up to 3 V(-1.44 to 1.6 V vs.Ag/AgCl).The Prussian blue(PB)/UGE/NaTi_(2)(PO_(4))_(3)@C full cell exhibits an exceptionally long lifespan of 10,000 cycles at 10 C.This study introduces a low-cost,ultra-long-life ASIB system,utilizing a green and economical eutectic electrolyte,which expands the use of eutectic electrolytes in aqueous batteries and opens a new research horizon for constructing efficient electrochemical energy storage and conversion.展开更多
Transformation of glycerol into value-added che micals via electro-oxidation using the green electricity is considered as a sustainable and promising process.Whereas,the synthesis of specific C3 products such as glyce...Transformation of glycerol into value-added che micals via electro-oxidation using the green electricity is considered as a sustainable and promising process.Whereas,the synthesis of specific C3 products such as glyceric acid(GLA)from electro-oxidation of glycerol still suffers from poor catalytic performance.Here,we used a two-step deposition strategy to prepare Au-CeO_(2)/CNT catalyst for highly efficient electrosynthesis of GLA from glycerol oxidation under alkaline conditions.Upon treating 0.5 mol/L glycerol at 1.12 V(vs.RHE)for 12 h in 1.0 mol/L KOH solution,the glycerol conversion and GLA selectivity over Au-CeO_(2)/CNT achieve 99.7%and 50.0%,respectively.The glycerol conversion doubles when an optimal amount of CeO_(2)is introduced to the Au/CNT catalyst,Au-CeO_(2)/CNT provides numerous active sites at ternary junctions of Au-CeO_(2)-CNT,which effectively suppress the adsorption of GLA on the surface of Au nanoparticles and prevent the nanoparticles from serious agglomeration,thereby facilitate the glycerol-to-GLA conversion with considerable cyclability.This study provides valuable insight into the rational design of high-performance catalysts for alcohol electro-oxidation.展开更多
Integrating electrochemical upgrading of glycerol and water electrolysis is regarded as a promising and energy-saving approach for the co-production of chemicals and hydrogen.However,developing efficient electrocataly...Integrating electrochemical upgrading of glycerol and water electrolysis is regarded as a promising and energy-saving approach for the co-production of chemicals and hydrogen.However,developing efficient electrocatalyst towards this technology remains challenging.Herein,a metallic cobalt mediated molybdenum nitride heterostructural material has been exploited on nickel foam(Co@Mo_(2)N/NF)for the glycerol oxidation reaction(GOR)and hydrogen evolution reaction(HER).Remarkably,the obtained Co@Mo_(2)N/NF realizes eminent performance with low overpotential of 49 mV at 50 mA/cm^(2)for HER and high Faradaic efficiency of formate of 95.03%at 1.35 V vs.RHE for GOR,respectively.The systematic in-situ experiments reveal that the Co@Mo_(2)N heterostructure promotes the cleavage of C-C bond in glycerol by active CoOOH species and boosts the conversion of glycerol to aldehyde intermediates to formate product.Moreover,the density functional theory(DFT)calculations confirm the strong interaction at Co@Mo_(2)N interface,which contributes to the optimized water dissociation and the transformation of H^(*)to H^(2).Benefiting from those advantages,the built HER||GOR electrolyzer delivers a low voltage of 1.61 V at 50 mA/cm^(2),high Faradaic efficiency,and robust stability over 120 h for sustained and stable electrolysis.展开更多
The electrocatalytic oxidation of glycerol toward formic acid is one of the most promising pathways for transformation and utilization of glycerol.Herein,a series of well-defined Ni_(n)(SR)_(2n) nanoclusters(n=4,5,6;d...The electrocatalytic oxidation of glycerol toward formic acid is one of the most promising pathways for transformation and utilization of glycerol.Herein,a series of well-defined Ni_(n)(SR)_(2n) nanoclusters(n=4,5,6;denoted as Ni NCs)were prepared for the electrocatalytic glycerol oxidation toward formic acid,in which Ni_(6)-PET-50CV afforded the most excellent electrocatalytic performance with a high formic acid selectivity of 93% and a high glycerol conversion of 86%.This was attributed to the lowest charge transfer impedance and the most rapid reaction kinetics.Combined electrochemical measurements and X-ray absorption fine structure measurements revealed that the structures of Ni NCs remained intact after CV scanning pretreatment and electrocatalysis via forming the Ni–O bond.Additionally,the kinetic studies and in-situ Fourier transformed infrared suggested a sequential oxidation mechanism,in which the main reaction steps of glycerol→glyceraldehyde→glyceric acid were very rapid to produce a high selectivity of formic acid even though the low glycerol conversion.This work presents an opportunity to study Ni NCs for the efficient electrocatalytic oxidation of biomass-derived polyhydroxyl platform molecules to produce value-added carboxylic acids.展开更多
Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites b...Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites by forming oxygen-bridged diatomic Ni-O-Ni confined in MOF-derived TiO_(2)(O-Ni_(2)/TiO_(2))via oxalic acid chelation.Among them,MOF-derived TiO_(2)scaffold provides a highly porous structure,supporting highly exposed active sites of Ni-O-Ni dimers linked by oxygen bridges.Density functional theory calculations show that the Ni-O-Ni sites regulate the local electronic structure of Ni sites,promoting the adsorption and activation of reactant molecules.Ultrafast spectroscopy shows that,in comparison with monomeric Ni/TiO_(2),the strong interaction in dimeric O-Ni_(2)/TiO_(2)tends to bring forth a more pronounced suppression of photogenerated electron-hole recombination,beneficial for achieving better charge separation and transfer as desired.As a direct outcome,the O-Ni_(2)/TiO_(2)photocatalyst has shown enhanced photocatalytic activity and selectivity in glycerol reforming reaction,with the average rates of H_(2)and CO evolution attaining as high as 2542.6 and 361.7μmol g^(-1)h^(-1),respectively,along with a remarkable selectivity of96.1%towards the syngas production(under a 365-nm light irradiation).Notably,the H_(2)and CO yields of the O-Ni_(2)/TiO_(2)photocatalyst are 3.9 and 6.7 times higher than those of the Ni/TiO_(2)photocatalyst,respectively.This study highlights the beneficial role of engineering the local electronic structure of atomicdispersed catalytic sites and provides an effective way for selective photocatalytic biomass conversion.展开更多
The electrochemical biomass valorization of industrial by-products or pollutants using renewable electricity offers significant promise for carbon neutrality.However,the huge challenges still exist in the development ...The electrochemical biomass valorization of industrial by-products or pollutants using renewable electricity offers significant promise for carbon neutrality.However,the huge challenges still exist in the development of efficient bifunctional electrocatalysts.Herein,we put forward a high-efficiency coelectrolysis system by coupling the nitrite reduction reaction(NO_(2)RR)and the glycerol oxidation reaction(GOR)over a novel heterogeneous β-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl catalyst.Theβ-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl shows excellent bifunctional performance with high Faradaic efficiencies of formate(90.1%)and NH_(3)(91.9%)at cell voltage of 1.5 V,high yield rate of formate(89.6 mg h^(-1)cm^(-2))and NH_(3)(36.07 mg h^(-1)cm^(-2))at cell voltage of 1.9 V,and superior stability in an anion exchange membrane co-electrolyzer.The in-situ Raman result confirms the unique Co/Cu-based bimetallic synergistic sites of β-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl towards superior GOR performance,while the operando Fourier transform infrared spectroscopy demonstrates the improved protonation kinetics of key intermediates and optimized water dissociation ability ofβ-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl for high NO_(2)RR activity.Our work illuminates alternative avenues to exploit the innovative and energy-saving technology for the co-production of high-added chemicals.展开更多
Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The dire...Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol carbonate.Deep investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.展开更多
Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in m...Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in microreactors remains challenging.In this investigation,a technique for creating Cu_(2)O/montmorillonite catalyst coating,using electrostatic attraction for layer-by-layer self-assembly,was proposed.The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite,alongside layer-by-layer coating times.The Cu_(2)O nanoparticles were immobilized using the flow deposition approach.The resulting Cu_(2)O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone.The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants,temperature,residence time,and Cu_(2)O loading.The maximum glycerol conversion observed was 47.6%,with a 27%selectivity toward dihydroxyacetone.The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing,which can serve as a foundation for the future application of microreactors in glycerol conversion.展开更多
Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial effect.The direct esterification of glycerol with lauric acid is the main method to synthesize GML.In this ...Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial effect.The direct esterification of glycerol with lauric acid is the main method to synthesize GML.In this work,the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst.A complete kinetic model of consecutive esterification reaction has been established,and the kinetic equation of acid catalysis was deduced.The isomerization reactions of GML and glycerol dilaurate were investigated.It was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification reaction.The kinetic equations of the consecutive esterification reaction were obtained by experiments as k_(1)=(276+92261Xcat)exp(-37720/RT)and k_(2)=(80+4413Xcat)exp(-32240/RT).The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.展开更多
An up-flow anaerobic sludge blanket(UASB)reactor targeting sulfate reduction was operated under a constant TOC/S-SO2-4ratio of 1.5±0.3 g C/g S for 639 days using crude glycerol as carbon source.A filamentous and ...An up-flow anaerobic sludge blanket(UASB)reactor targeting sulfate reduction was operated under a constant TOC/S-SO2-4ratio of 1.5±0.3 g C/g S for 639 days using crude glycerol as carbon source.A filamentous and fluffy flocculant material,namely slime-like substances(SLS),was gradually accumulated in the bioreactor after the cease of methanogenic activity.The accumulation of SLS was followed by a decrease in the removal efficiencies and a deterioration in the performance.Selected characteristics of SLS were investigated to explore the causes of its formation and the effect of SLS on the UASB performance.Results showed that glycerol fermentation and sulfate reduction processes taking place in the reactor were mainly accomplished in the bottom part of the UASB reactor,as the sludge concentration in the bottom was higher.The accumulation of SLS in the UASB reactor caused sludge flotation that further led to biomass washout,which decreased the sulfate and glycerol removal efficiencies.Batch activity tests performed with granular sludge(GS),slime-covered granular sludge(SCGS)and SLS showed that there was no difference between GS and SLS in the mechanism of glycerol fermentation and sulfate reduction.However,the specific sulfate reduction rate of GS was higher than that of SLS,while SLS showed a higher glycerol fermentation rate than that of GS.The different rates in GS and SLS were attributed to the higher relative abundances of fermentative microorganisms found in SLS and higher relative abundances of sulfate reducing bacteria(SRB)found in GS.展开更多
The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the ca...The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the catalyst deactivation via sintering,metal leaching,and coking can predominantly occur in the aqueous phase reaction.In this work,the effect of reaction temperature,pressure and second promoter(Cu,Fe,Rh,Mn,Re,Ru,Ir,Sn,B,and P)on catalytic performance and deactivation behaviour of Pt/WOx/-Al2O3 was investigated.When doped with Rh,Mn,Re,Ru,Ir,B,and P,the second promoter boosts catalytic activity by promoting great dispersion of Pt on support and increasing Pt surface area.The increased Bronsted acid sites lead to selective synthesis of 1,3-PDO than 1,2-propanediol(1,2-PDO).The characterization studies of fresh and spent catalysts reveal that the main cause of catalyst deactivation is the Pt sintering,as interpreted based on XRD,CO chemisorption,and TEM analyses.The Pt sintering is affected depending on the second promoter that can either or reduce the interaction between Pt,WO_(χ)/γ and Al_(2)O_(3).As an electron acceptor of Pt in Pt/WO_(χ)/γ-Al_(2)O_(3),Re and Mn as second promoters resulted in increased Pt^(2+) on the catalytic surface,which strengthens the contact between Pt andγ-Al_(2)O_(3) and WO_(χ),resulting in a decrease in Pt sintering.The metal leaching and coking are not affected by the presence of second promoter.The catalyst modified with a second promoter possesses improved catalytic activity and 1,3-PDO production,however the stability continues to remain a challenge.The present work unrav-elled the determining parameters of catalytic activity and deactivation,thus providing a promising pro-tocol toward effective catalysts for glycerol hydrogenolysis.展开更多
The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization.In this work,Au nanowires(Au-NW)modified with polyethyleneimine(PEI)molecu...The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization.In this work,Au nanowires(Au-NW)modified with polyethyleneimine(PEI)molecule(Au-NW@PEI)is obtained by an up-bottom post-modification approach.Physical characterization,molecular dynamics simulation and density functional theory demonstrate that the loose-packed PEI monolayer firmly and uniformly distribute on the Au-NW surface due to the strong Au-N interaction.Electrochemical experiments and product analysis display that PEI modification significantly enhance the electro-activity of Au-NW for the glycerol electro-oxidation reaction(GEOR)due to the electronic effect.Meanwhile,the steric hindrance and electrostatic effect of PEI layer make the optimizing adsorption of intermediates possible.Therefore,the selectivity of C3 product glyceric acid over Au-NW@PEI is increased by nearly 20%.The work thus indicates that the rational design of metal-organic interface can effectively elevate the electro-activity and selectivity of Au nanostructures,which may have wide application in biomass development.展开更多
Glycerol-assisted instant catapult steam explosion(ICSE)of lignocellulose is an effective pretreatment method for enhancing sugar production compared to glycerol-free ICSE.In this study,glycerol-assisted ICSE of corn ...Glycerol-assisted instant catapult steam explosion(ICSE)of lignocellulose is an effective pretreatment method for enhancing sugar production compared to glycerol-free ICSE.In this study,glycerol-assisted ICSE of corn stover was studied in order to understand the reaction mechanisms and further optimize the process.Results showed that water extraction of corn stover prior to ICSE reduced pseudo-lignin formation.The combination of water extraction and glycerol-assisted ICSE led to the formation of lignin with a lower molecular weight(Mw)of 2851 g/mol than 3521 g/mole of that from the combination of water extraction and glycerol-free ICSE.1H-13C NMR analysis revealed that glycerol likely reacted with lignin carboxylic OHs through esterification while etherification of aliphatic OHs was not observed in ICSE.These lignin analyses indicated that glycerol protected lignin from condensation/repolymerization during glycerol-assisted ICSE.Enzymatic hydrolysis results showed that without water extraction increasing glycerol usage from 0.2 kg/kg stover to 0.4 kg/kg stover improved glucan digestibility to 78%but further increase to 0.5 kg/kg stover reduced glucan digestibility.In addition,at the glycerol usage of 0.2-0.4 kg/kg stover,washing of pretreated stover for removal of glycerol and other biomass-derived compounds did not improve glucan digestibility compared to unwashed ones.Combination of water extraction and glycerol-assisted ICSE led to a high glucan digestibility of 89.7%and a total glucose yield of 25.5 g glucose/100 g stover,which were 30.1%and 7.5 g/100 g stover higher than those derived from glycerol-free ICSE of stover,respectively.Since glycerol is a low-cost carbon source,the resulting enzymatic hydrolysate that contained both glucose and glycerol may be directly used to produce bioproducts by microbial fermentation.展开更多
Selective oxidation of glycerol is a hot topic.Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied.However,Pt catalysts suffer from deactivation because of...Selective oxidation of glycerol is a hot topic.Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied.However,Pt catalysts suffer from deactivation because of weak metal-support interactions.In this study,multi-walled carbon nanotube（MWCNTs）-pillared nitrogen-doped graphene（NG） was prepared by direct pyrolysis of melamine on MWCNTs,and the synthesized NG-MWCNT composite was used as the support for Pt.Characterization results showed that the surface area（173 m^2/g） and pore volume of the NG-MWCNT composite were greater than those of bare MWCNTs and the separated melamine pyrolysis product（CH_x）.Pt（1.4±0.4 nm） dispersion on the NG-MWCNTs was favorable and the Pt/NG-MWCNT catalyst was highly active and selective in the oxidation of glycerol to glyceric acid（GLYA） in base-free aqueous solution.For example,the conversion of glycerol reached 64.4% with a GLYA selectivity of 81.0%,whereas the conversions of glycerol over Pt/MWCNTs and Pt/CN_x were 29.0% and 31.6%,respectively.The unique catalytic activity of the Pt/NG-MWCNTs is attributed to well-dispersed Pt clusters on the NG-MWCNTs and the electron-donating effect of the nitrogen dopant in the NG-MWCNTs.展开更多
Pt/activated carbon （Pt/AC） catalyst combined with base works efficiently for lactic acid production from glycerol under mild conditions. Base type （LiOH, NaOH, KOH, or Ba（OH）2） and base/glycerol molar ratio sig...Pt/activated carbon （Pt/AC） catalyst combined with base works efficiently for lactic acid production from glycerol under mild conditions. Base type （LiOH, NaOH, KOH, or Ba（OH）2） and base/glycerol molar ratio significantly affected the catalytic performance. The corresponding lactic acid selectivity was in the order of LiOH〉NaOH〉KOH〉Ba（OH）2. An increase in LiOH/glycerol molar ratio ele‐vated the glycerol conversion and lactic acid selectivity to some degree, but excess LiOH inhibited the transformation of glycerol to lactic acid. In the presence of Pt/AC catalyst, the maximum selec‐tivity of lactic acid was 69.3% at a glycerol conversion of 100% after 6 h at 90 °C, with a Li‐OH/glycerol molar ratio of 1.5. The Pt/AC catalyst was recycled five times and was found to exhibit slightly decreased glycerol conversion and stable lactic acid selectivity. In addition, the experimental results indicated that reaction intermediate dihydroxyacetone was more favorable as the starting reagent for lactic acid formation than glyceraldehyde. However, the Pt/AC catalyst had adverse effects on the intermediate transformation to lactic acid, because it favored the catalytic oxidation of them to glyceric acid.展开更多
Energy-saving glycerol electrolysis with lower potential than water spitting endows a promising way for the concurrent production of value-added formate and high-purity hydrogen. However, there is still lack of effici...Energy-saving glycerol electrolysis with lower potential than water spitting endows a promising way for the concurrent production of value-added formate and high-purity hydrogen. However, there is still lack of efficient electrocatalysts at both anode and cathode for glycerol electrolysis. Herein, we report the activation of Ni site in NiV layered double hydroxide(LDH) by electrochemical and N_(2)/H_(2) plasma regulations for boosting the activity of glycerol oxidation reaction(GOR) and hydrogen evolution reaction(HER), respectively. Specifically, boosted GOR performance with a low overpotential(1.23 V at 10 mA·cm^(-2)) and a high Faradic efficiency(94%) is demonstrated by electrochemically regulated NiV LDH(ENiV LDH) with elevated valence state of Ni site. In situ Raman spectrum reveals the generation of Ni(Ⅲ) species by electrochemical regulation, and the highly active Ni(Ⅲ)can be regenerated with the process of electrochemical oxidation. Additionally, the possible reaction pathway is speculated based on the in situ Fourier transform infrared spectroscopy(FTIR) and high-performance liquid chromatography results. The plasma-regulated NiV LDH(PNiV LDH) with lower valence state of Ni site exhibits outstanding HER activity, displaying a low overpotential of 45 m V to deliver 10 mA·cm^(-2).When employing E-NiV LDH and P-NiV LDH as anode and cathode electrocatalyst, respectively, the assembled electrolyzer merely needs 1.25 V to achieve 10 m A·cm^(-2) for simultaneous production of formate and hydrogen, demonstrating remarkable 320 mV of lower potential than water electrolysis.展开更多
This research was focused on the valorisation of glycerol,exploring the feasibility of an efficient route for oxygenated additives production based on its etherification with bio-butanol.A home-made BEA zeolite sample...This research was focused on the valorisation of glycerol,exploring the feasibility of an efficient route for oxygenated additives production based on its etherification with bio-butanol.A home-made BEA zeolite sample with a tuneable acidity has been proposed as the catalytic system,being tested in a stirred reactor under different etherification conditions.Although a reaction temperature as high as 200℃resulted to be beneficial in terms of glycerol conversion(-90%),only by operating at milder conditions the product selectivity to glycerol-ethers can be better controlled,in order to obtain a bio-fuel complying with the requirements for mixing with fossil diesel or biodiesel,without any need of purification from large amount of by-products.A comprehensive identification of all the compounds formed during the reaction was performed by a GC-MS analysis,on the basis of the complex network of consecutive and parallel reaction paths leading not only to the desired ethers,but also to many side products not detected in similar acid-catalyzed reactions in liquid phase and not available in the most used mass-spectra libraries.展开更多
Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acid...Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.展开更多
基金supported by Fundamental Research Program of Shanxi Province(202203021221303)。
文摘Transformation of urea and glycerol to glycerol carbonate is an environmental friendly and economical process.Catalysts play an indispensable role in the process.Although many catalysts have been developed,the performance of the catalysts still cannot meet the needs of industrialization.In this paper,research progress of the homogeneous and heterogeneous catalysts of the reaction over the past 20 years were reviewed systematically.According to the types and active centers of catalysts,the catalysts were classified systematically and analyzed in detail.The typical reaction mechanisms were also summarized.The research and development direction of catalysts is made more explicit through systematic classification and mechanism analysis.The article reveals more novel catalysts have been designed and used for the reaction,such as mixed metal oxides with special structures,solid wastes and non-metallic materials.This work summarized the current state of research and prospected possible routes for design of novel catalysts.It is hoped that this review can provide some references for developing efficient catalysts.
基金National Natural Science Foundation of China (Nos. 42276035, 22309030)Guangdong Basic and Applied Basic Research Foundation (Nos. 2023A1515012589,2020A1515110473)Key Plat Form Programs and Technology Innovation Team Project of Guangdong Provincial Department of Education (Nos. 2019GCZX002, 2020KCXTD011)。
文摘Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corrosion caused by the harmful chlorine.In contrast to the oxygen evolution reaction (OER)and chlorin ion oxidation reaction (ClOR),glycerol oxidation reaction (GOR) is more thermodynamically and kinetically favorable alternative.Herein,a Ru doping cobalt phosphide (Ru-CoP_(2)) is proposed as a robust bifunctional electrocatalyst for seawater electrolysis and GOR,for the concurrent productions of hydrogen and value-added formate.The in situ and ex situ characterization analyses demonstrated that Ru doping featured in the dynamic reconstruction process from Ru-CoP_(2)to Ru-CoOOH,accounting for the superior GOR performance.Further coupling GOR with hydrogen evolution was realized by employing Ru-CoP_(2)as both anode and cathode,requiring only a low voltage of 1.43 V at 100 mA cm^(-2),which was 250 m V lower than that in alkaline seawater.This work guides the design of bifunctional electrocatalysts for energy-efficient seawater electrolysis coupled with biomass resource upcycling.
基金support by the Department of Science&Technology of Zhejiang Province under grant No.2024C01095the Fundamental Research Funds for the Provincial Universities of Zhejiang under grant No.RF-C2022008the National Natural Science Foundation of China(NSFC)under grant Nos.U20A20253,52372235,and 22279116。
文摘Aqueous sodium-ion batteries(ASIBs)have garnered significant attention as promising candidates for large-scale energy storage applications.This interest is primarily due to their abundant resource availability,environmental friendliness,cost-effectiveness,and high safety.However,their electrochemical performance is limited by the thermodynamic properties of water molecules,resulting in inadequate cycling stability and insufficient specific energy density.To address these challenges,this study developed a hydrogen-bond enhanced urea-glycerol eutectic electrolyte(UGE)to expand the electrochemical stability window(ESW)of the electrolyte and suppress corresponding side reactions.The eutectic component disrupts the original hydrogen bonding network in water,creating a new,enhanced network that reduces the activity of free water and forms a uniform,dense passivation layer on the anode.As a result,the optimized composition of UGE exhibits a broad ESW of up to 3 V(-1.44 to 1.6 V vs.Ag/AgCl).The Prussian blue(PB)/UGE/NaTi_(2)(PO_(4))_(3)@C full cell exhibits an exceptionally long lifespan of 10,000 cycles at 10 C.This study introduces a low-cost,ultra-long-life ASIB system,utilizing a green and economical eutectic electrolyte,which expands the use of eutectic electrolytes in aqueous batteries and opens a new research horizon for constructing efficient electrochemical energy storage and conversion.
基金Project supported by the National Natural Science Foundation of China(22161033,21875125)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2023ZD11)+1 种基金the 111 Project(D20033)the"Grassland Talent"Program and"Grassland Talent"Innovation Team of Inner Mongolia。
文摘Transformation of glycerol into value-added che micals via electro-oxidation using the green electricity is considered as a sustainable and promising process.Whereas,the synthesis of specific C3 products such as glyceric acid(GLA)from electro-oxidation of glycerol still suffers from poor catalytic performance.Here,we used a two-step deposition strategy to prepare Au-CeO_(2)/CNT catalyst for highly efficient electrosynthesis of GLA from glycerol oxidation under alkaline conditions.Upon treating 0.5 mol/L glycerol at 1.12 V(vs.RHE)for 12 h in 1.0 mol/L KOH solution,the glycerol conversion and GLA selectivity over Au-CeO_(2)/CNT achieve 99.7%and 50.0%,respectively.The glycerol conversion doubles when an optimal amount of CeO_(2)is introduced to the Au/CNT catalyst,Au-CeO_(2)/CNT provides numerous active sites at ternary junctions of Au-CeO_(2)-CNT,which effectively suppress the adsorption of GLA on the surface of Au nanoparticles and prevent the nanoparticles from serious agglomeration,thereby facilitate the glycerol-to-GLA conversion with considerable cyclability.This study provides valuable insight into the rational design of high-performance catalysts for alcohol electro-oxidation.
基金financially supported by the National Natural Science Foundation of China(No.22205205)the Natural Science Foundation of Zhejiang Province(No.LQ24E040002)the Science Foundation of Zhejiang Sci-Tech University(ZSTU)(Nos.21062337Y,LW-YP2024076)。
文摘Integrating electrochemical upgrading of glycerol and water electrolysis is regarded as a promising and energy-saving approach for the co-production of chemicals and hydrogen.However,developing efficient electrocatalyst towards this technology remains challenging.Herein,a metallic cobalt mediated molybdenum nitride heterostructural material has been exploited on nickel foam(Co@Mo_(2)N/NF)for the glycerol oxidation reaction(GOR)and hydrogen evolution reaction(HER).Remarkably,the obtained Co@Mo_(2)N/NF realizes eminent performance with low overpotential of 49 mV at 50 mA/cm^(2)for HER and high Faradaic efficiency of formate of 95.03%at 1.35 V vs.RHE for GOR,respectively.The systematic in-situ experiments reveal that the Co@Mo_(2)N heterostructure promotes the cleavage of C-C bond in glycerol by active CoOOH species and boosts the conversion of glycerol to aldehyde intermediates to formate product.Moreover,the density functional theory(DFT)calculations confirm the strong interaction at Co@Mo_(2)N interface,which contributes to the optimized water dissociation and the transformation of H^(*)to H^(2).Benefiting from those advantages,the built HER||GOR electrolyzer delivers a low voltage of 1.61 V at 50 mA/cm^(2),high Faradaic efficiency,and robust stability over 120 h for sustained and stable electrolysis.
文摘The electrocatalytic oxidation of glycerol toward formic acid is one of the most promising pathways for transformation and utilization of glycerol.Herein,a series of well-defined Ni_(n)(SR)_(2n) nanoclusters(n=4,5,6;denoted as Ni NCs)were prepared for the electrocatalytic glycerol oxidation toward formic acid,in which Ni_(6)-PET-50CV afforded the most excellent electrocatalytic performance with a high formic acid selectivity of 93% and a high glycerol conversion of 86%.This was attributed to the lowest charge transfer impedance and the most rapid reaction kinetics.Combined electrochemical measurements and X-ray absorption fine structure measurements revealed that the structures of Ni NCs remained intact after CV scanning pretreatment and electrocatalysis via forming the Ni–O bond.Additionally,the kinetic studies and in-situ Fourier transformed infrared suggested a sequential oxidation mechanism,in which the main reaction steps of glycerol→glyceraldehyde→glyceric acid were very rapid to produce a high selectivity of formic acid even though the low glycerol conversion.This work presents an opportunity to study Ni NCs for the efficient electrocatalytic oxidation of biomass-derived polyhydroxyl platform molecules to produce value-added carboxylic acids.
基金supported by the National Key R&D Program of China(2022YFA1503003)the National Natural Science Foundation of China(U24A20550,52273264,22173090)+2 种基金the Youth Scienceof China(22409056)the Innovation Program for Quantum Science and Technology(2021ZD0303303)the Key Project of the Heilongjiang Provincial Natural Science Foundation(ZD2024B001)。
文摘Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites by forming oxygen-bridged diatomic Ni-O-Ni confined in MOF-derived TiO_(2)(O-Ni_(2)/TiO_(2))via oxalic acid chelation.Among them,MOF-derived TiO_(2)scaffold provides a highly porous structure,supporting highly exposed active sites of Ni-O-Ni dimers linked by oxygen bridges.Density functional theory calculations show that the Ni-O-Ni sites regulate the local electronic structure of Ni sites,promoting the adsorption and activation of reactant molecules.Ultrafast spectroscopy shows that,in comparison with monomeric Ni/TiO_(2),the strong interaction in dimeric O-Ni_(2)/TiO_(2)tends to bring forth a more pronounced suppression of photogenerated electron-hole recombination,beneficial for achieving better charge separation and transfer as desired.As a direct outcome,the O-Ni_(2)/TiO_(2)photocatalyst has shown enhanced photocatalytic activity and selectivity in glycerol reforming reaction,with the average rates of H_(2)and CO evolution attaining as high as 2542.6 and 361.7μmol g^(-1)h^(-1),respectively,along with a remarkable selectivity of96.1%towards the syngas production(under a 365-nm light irradiation).Notably,the H_(2)and CO yields of the O-Ni_(2)/TiO_(2)photocatalyst are 3.9 and 6.7 times higher than those of the Ni/TiO_(2)photocatalyst,respectively.This study highlights the beneficial role of engineering the local electronic structure of atomicdispersed catalytic sites and provides an effective way for selective photocatalytic biomass conversion.
基金financially supported by the National Natural Science Foundation of China(22205205)the Science Foundation of Zhejiang Sci-Tech University(ZSTU)under Grant No.21062337-Y。
文摘The electrochemical biomass valorization of industrial by-products or pollutants using renewable electricity offers significant promise for carbon neutrality.However,the huge challenges still exist in the development of efficient bifunctional electrocatalysts.Herein,we put forward a high-efficiency coelectrolysis system by coupling the nitrite reduction reaction(NO_(2)RR)and the glycerol oxidation reaction(GOR)over a novel heterogeneous β-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl catalyst.Theβ-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl shows excellent bifunctional performance with high Faradaic efficiencies of formate(90.1%)and NH_(3)(91.9%)at cell voltage of 1.5 V,high yield rate of formate(89.6 mg h^(-1)cm^(-2))and NH_(3)(36.07 mg h^(-1)cm^(-2))at cell voltage of 1.9 V,and superior stability in an anion exchange membrane co-electrolyzer.The in-situ Raman result confirms the unique Co/Cu-based bimetallic synergistic sites of β-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl towards superior GOR performance,while the operando Fourier transform infrared spectroscopy demonstrates the improved protonation kinetics of key intermediates and optimized water dissociation ability ofβ-Co(OH)_(2)/Cu_(2)(OH)_(3)Cl for high NO_(2)RR activity.Our work illuminates alternative avenues to exploit the innovative and energy-saving technology for the co-production of high-added chemicals.
基金Financial support from the National Key Research and Development Program of China(2022YFB3805602)the National Natural Science Foundation of China(22138001,22288102)the Fundamental Research Funds for the Central Universities。
文摘Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol carbonate.Deep investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.
基金support from the National Natural Science Foundation of China(2207213641672033)+2 种基金the research grants from Engineering Research Center of Non-metallic Minerals of Zhejiang Province(ZD2023K01)the projects from Qing Yang Institute for Industrial Minerals(KYYHX-20220336KYY-HX-20170557).
文摘Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in microreactors remains challenging.In this investigation,a technique for creating Cu_(2)O/montmorillonite catalyst coating,using electrostatic attraction for layer-by-layer self-assembly,was proposed.The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite,alongside layer-by-layer coating times.The Cu_(2)O nanoparticles were immobilized using the flow deposition approach.The resulting Cu_(2)O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone.The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants,temperature,residence time,and Cu_(2)O loading.The maximum glycerol conversion observed was 47.6%,with a 27%selectivity toward dihydroxyacetone.The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing,which can serve as a foundation for the future application of microreactors in glycerol conversion.
基金supported by the National Research and Development Program of China(2021YFC3001100)the National Natural Science Foundation of China(22288102).
文摘Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial effect.The direct esterification of glycerol with lauric acid is the main method to synthesize GML.In this work,the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst.A complete kinetic model of consecutive esterification reaction has been established,and the kinetic equation of acid catalysis was deduced.The isomerization reactions of GML and glycerol dilaurate were investigated.It was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification reaction.The kinetic equations of the consecutive esterification reaction were obtained by experiments as k_(1)=(276+92261Xcat)exp(-37720/RT)and k_(2)=(80+4413Xcat)exp(-32240/RT).The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.
基金the Spanish Government,through the project RTI2018-099362-B-C21 MINECO/FEDER,EU,for the financial support provided to perform this researchthe China Scholarship Council (CSC,201706300052)for financial support。
文摘An up-flow anaerobic sludge blanket(UASB)reactor targeting sulfate reduction was operated under a constant TOC/S-SO2-4ratio of 1.5±0.3 g C/g S for 639 days using crude glycerol as carbon source.A filamentous and fluffy flocculant material,namely slime-like substances(SLS),was gradually accumulated in the bioreactor after the cease of methanogenic activity.The accumulation of SLS was followed by a decrease in the removal efficiencies and a deterioration in the performance.Selected characteristics of SLS were investigated to explore the causes of its formation and the effect of SLS on the UASB performance.Results showed that glycerol fermentation and sulfate reduction processes taking place in the reactor were mainly accomplished in the bottom part of the UASB reactor,as the sludge concentration in the bottom was higher.The accumulation of SLS in the UASB reactor caused sludge flotation that further led to biomass washout,which decreased the sulfate and glycerol removal efficiencies.Batch activity tests performed with granular sludge(GS),slime-covered granular sludge(SCGS)and SLS showed that there was no difference between GS and SLS in the mechanism of glycerol fermentation and sulfate reduction.However,the specific sulfate reduction rate of GS was higher than that of SLS,while SLS showed a higher glycerol fermentation rate than that of GS.The different rates in GS and SLS were attributed to the higher relative abundances of fermentative microorganisms found in SLS and higher relative abundances of sulfate reducing bacteria(SRB)found in GS.
基金funded by the National Research Council of Thailand (NRCT)the Second Century Foundation (C2F),Chulalongkorn University,ThailandResearcher Supporting Project RSP2024RR400,King Saud University,Saudi Arabia
文摘The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the catalyst deactivation via sintering,metal leaching,and coking can predominantly occur in the aqueous phase reaction.In this work,the effect of reaction temperature,pressure and second promoter(Cu,Fe,Rh,Mn,Re,Ru,Ir,Sn,B,and P)on catalytic performance and deactivation behaviour of Pt/WOx/-Al2O3 was investigated.When doped with Rh,Mn,Re,Ru,Ir,B,and P,the second promoter boosts catalytic activity by promoting great dispersion of Pt on support and increasing Pt surface area.The increased Bronsted acid sites lead to selective synthesis of 1,3-PDO than 1,2-propanediol(1,2-PDO).The characterization studies of fresh and spent catalysts reveal that the main cause of catalyst deactivation is the Pt sintering,as interpreted based on XRD,CO chemisorption,and TEM analyses.The Pt sintering is affected depending on the second promoter that can either or reduce the interaction between Pt,WO_(χ)/γ and Al_(2)O_(3).As an electron acceptor of Pt in Pt/WO_(χ)/γ-Al_(2)O_(3),Re and Mn as second promoters resulted in increased Pt^(2+) on the catalytic surface,which strengthens the contact between Pt andγ-Al_(2)O_(3) and WO_(χ),resulting in a decrease in Pt sintering.The metal leaching and coking are not affected by the presence of second promoter.The catalyst modified with a second promoter possesses improved catalytic activity and 1,3-PDO production,however the stability continues to remain a challenge.The present work unrav-elled the determining parameters of catalytic activity and deactivation,thus providing a promising pro-tocol toward effective catalysts for glycerol hydrogenolysis.
基金sponsored by National Natural Science Foundation of China(No.22202130)China Postdoctoral Science Foundation(No.2022M710088)+3 种基金Science and Technology Innovation Team of Shaanxi Province(Nos.2023-CX-TD-27 and 2022TD-35)Fundamental Research Funds for the Central Universities(Nos.GK202202001 and GK202101005)Open Funds of the State Key Laboratory of Electroanalytical Chemistry(No.SKLEAC202207)the 111 Project(No.B14041)。
文摘The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization.In this work,Au nanowires(Au-NW)modified with polyethyleneimine(PEI)molecule(Au-NW@PEI)is obtained by an up-bottom post-modification approach.Physical characterization,molecular dynamics simulation and density functional theory demonstrate that the loose-packed PEI monolayer firmly and uniformly distribute on the Au-NW surface due to the strong Au-N interaction.Electrochemical experiments and product analysis display that PEI modification significantly enhance the electro-activity of Au-NW for the glycerol electro-oxidation reaction(GEOR)due to the electronic effect.Meanwhile,the steric hindrance and electrostatic effect of PEI layer make the optimizing adsorption of intermediates possible.Therefore,the selectivity of C3 product glyceric acid over Au-NW@PEI is increased by nearly 20%.The work thus indicates that the rational design of metal-organic interface can effectively elevate the electro-activity and selectivity of Au nanostructures,which may have wide application in biomass development.
基金supported by the Henan Provincial Science and Technology Research Project(222102520015)the Science and Technology Innovation Leading Talents of Central Plains,Henan province,China(204200510018).
文摘Glycerol-assisted instant catapult steam explosion(ICSE)of lignocellulose is an effective pretreatment method for enhancing sugar production compared to glycerol-free ICSE.In this study,glycerol-assisted ICSE of corn stover was studied in order to understand the reaction mechanisms and further optimize the process.Results showed that water extraction of corn stover prior to ICSE reduced pseudo-lignin formation.The combination of water extraction and glycerol-assisted ICSE led to the formation of lignin with a lower molecular weight(Mw)of 2851 g/mol than 3521 g/mole of that from the combination of water extraction and glycerol-free ICSE.1H-13C NMR analysis revealed that glycerol likely reacted with lignin carboxylic OHs through esterification while etherification of aliphatic OHs was not observed in ICSE.These lignin analyses indicated that glycerol protected lignin from condensation/repolymerization during glycerol-assisted ICSE.Enzymatic hydrolysis results showed that without water extraction increasing glycerol usage from 0.2 kg/kg stover to 0.4 kg/kg stover improved glucan digestibility to 78%but further increase to 0.5 kg/kg stover reduced glucan digestibility.In addition,at the glycerol usage of 0.2-0.4 kg/kg stover,washing of pretreated stover for removal of glycerol and other biomass-derived compounds did not improve glucan digestibility compared to unwashed ones.Combination of water extraction and glycerol-assisted ICSE led to a high glucan digestibility of 89.7%and a total glucose yield of 25.5 g glucose/100 g stover,which were 30.1%and 7.5 g/100 g stover higher than those derived from glycerol-free ICSE of stover,respectively.Since glycerol is a low-cost carbon source,the resulting enzymatic hydrolysate that contained both glucose and glycerol may be directly used to produce bioproducts by microbial fermentation.
基金financially supported by the National Natural Science Foundation of China(21473155,21273198,21073159)Natural Science Foundation of Zhejiang Province(L12B03001)the foundation from State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology(GCTKF2014009)~~
文摘Selective oxidation of glycerol is a hot topic.Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied.However,Pt catalysts suffer from deactivation because of weak metal-support interactions.In this study,multi-walled carbon nanotube（MWCNTs）-pillared nitrogen-doped graphene（NG） was prepared by direct pyrolysis of melamine on MWCNTs,and the synthesized NG-MWCNT composite was used as the support for Pt.Characterization results showed that the surface area（173 m^2/g） and pore volume of the NG-MWCNT composite were greater than those of bare MWCNTs and the separated melamine pyrolysis product（CH_x）.Pt（1.4±0.4 nm） dispersion on the NG-MWCNTs was favorable and the Pt/NG-MWCNT catalyst was highly active and selective in the oxidation of glycerol to glyceric acid（GLYA） in base-free aqueous solution.For example,the conversion of glycerol reached 64.4% with a GLYA selectivity of 81.0%,whereas the conversions of glycerol over Pt/MWCNTs and Pt/CN_x were 29.0% and 31.6%,respectively.The unique catalytic activity of the Pt/NG-MWCNTs is attributed to well-dispersed Pt clusters on the NG-MWCNTs and the electron-donating effect of the nitrogen dopant in the NG-MWCNTs.
基金supported by the National Natural Science Foundation of China(21176236)~~
文摘Pt/activated carbon （Pt/AC） catalyst combined with base works efficiently for lactic acid production from glycerol under mild conditions. Base type （LiOH, NaOH, KOH, or Ba（OH）2） and base/glycerol molar ratio significantly affected the catalytic performance. The corresponding lactic acid selectivity was in the order of LiOH〉NaOH〉KOH〉Ba（OH）2. An increase in LiOH/glycerol molar ratio ele‐vated the glycerol conversion and lactic acid selectivity to some degree, but excess LiOH inhibited the transformation of glycerol to lactic acid. In the presence of Pt/AC catalyst, the maximum selec‐tivity of lactic acid was 69.3% at a glycerol conversion of 100% after 6 h at 90 °C, with a Li‐OH/glycerol molar ratio of 1.5. The Pt/AC catalyst was recycled five times and was found to exhibit slightly decreased glycerol conversion and stable lactic acid selectivity. In addition, the experimental results indicated that reaction intermediate dihydroxyacetone was more favorable as the starting reagent for lactic acid formation than glyceraldehyde. However, the Pt/AC catalyst had adverse effects on the intermediate transformation to lactic acid, because it favored the catalytic oxidation of them to glyceric acid.
基金the National Science Foundation of China(No.12075002)the Outstanding Youth Fund of Anhui Province(No.2008085J21)+1 种基金Anhui Provincial Supporting Program for Excellent Young Talents in Universities(No.gxyqZD2019005)the Innovation and Entrepreneurship Project of Overseas Returnees in Anhui Province(No.2019LCX018)。
文摘Energy-saving glycerol electrolysis with lower potential than water spitting endows a promising way for the concurrent production of value-added formate and high-purity hydrogen. However, there is still lack of efficient electrocatalysts at both anode and cathode for glycerol electrolysis. Herein, we report the activation of Ni site in NiV layered double hydroxide(LDH) by electrochemical and N_(2)/H_(2) plasma regulations for boosting the activity of glycerol oxidation reaction(GOR) and hydrogen evolution reaction(HER), respectively. Specifically, boosted GOR performance with a low overpotential(1.23 V at 10 mA·cm^(-2)) and a high Faradic efficiency(94%) is demonstrated by electrochemically regulated NiV LDH(ENiV LDH) with elevated valence state of Ni site. In situ Raman spectrum reveals the generation of Ni(Ⅲ) species by electrochemical regulation, and the highly active Ni(Ⅲ)can be regenerated with the process of electrochemical oxidation. Additionally, the possible reaction pathway is speculated based on the in situ Fourier transform infrared spectroscopy(FTIR) and high-performance liquid chromatography results. The plasma-regulated NiV LDH(PNiV LDH) with lower valence state of Ni site exhibits outstanding HER activity, displaying a low overpotential of 45 m V to deliver 10 mA·cm^(-2).When employing E-NiV LDH and P-NiV LDH as anode and cathode electrocatalyst, respectively, the assembled electrolyzer merely needs 1.25 V to achieve 10 m A·cm^(-2) for simultaneous production of formate and hydrogen, demonstrating remarkable 320 mV of lower potential than water electrolysis.
文摘This research was focused on the valorisation of glycerol,exploring the feasibility of an efficient route for oxygenated additives production based on its etherification with bio-butanol.A home-made BEA zeolite sample with a tuneable acidity has been proposed as the catalytic system,being tested in a stirred reactor under different etherification conditions.Although a reaction temperature as high as 200℃resulted to be beneficial in terms of glycerol conversion(-90%),only by operating at milder conditions the product selectivity to glycerol-ethers can be better controlled,in order to obtain a bio-fuel complying with the requirements for mixing with fossil diesel or biodiesel,without any need of purification from large amount of by-products.A comprehensive identification of all the compounds formed during the reaction was performed by a GC-MS analysis,on the basis of the complex network of consecutive and parallel reaction paths leading not only to the desired ethers,but also to many side products not detected in similar acid-catalyzed reactions in liquid phase and not available in the most used mass-spectra libraries.
基金the financial support from Scientific Research Foundation for Doctoral Program of Liaoning Province(20081104)
文摘Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.
