Fabrication Of High-Efficiency Transition Metal(Co,Ni)Catalysts And Their Catalytic Performance In Biomass Upgrading

Biomass,as one of the most important clean and sustainable energy sources,can be converted into a series of high-valued biofuels and fine chemicals.This green route for producing fuels and chemicals can greatly reduce the consumption of fossil resources and alleviate environmental pollution.So far,the research for biomass conversion mainly focus on the development of cheap,efficient and stable catalysts and the design of new catalytic system.In view of the problems existed in experimental and industrial catalysis,such as low catalytic activity,easy leaching and sintering of active metals,extensive use of organic solvents and harsh reaction conditions,in-depth research and discussion have been carried out.To this end,we construct several high active and stable transition metals(Co,Ni)catalytic material using simple and effective methods,which can realize the catalytic conversion of a wide range of biomass-derived platform compounds(furfural,vanillin,etc.)under water solvent and realatively moderate reaction conditions.The corresponding reaction pathways,catalytic mechanisms and structure-function relationships have further been reveled by combining related characterizations and theoretical calculations.In addition,we also explored an efficient electrocatalytic system to catalytic oxidation of 5-hydroxymethylfurfural using water as an oxygen source at room temperature and atmospheric pressure,which showing great potential for biomass upgrading.The main contents of the research are shown as follows:1.The cyclopentanone and its derivatives are a class of crucial fine chemicals for various industries and currently produced by conventional petrochemical synthetic routes.Here,we demonstrated a new synthetic approach to directly fabricate N-doped carbon nanotubes(N-CNTs)networks with confined Co nanoparticles(NPs)from Co2+-impregnated bulk g-C3N4 as high performance hydrogenation rearrangement(HR)catalyst to efficiently convert a wide range of biomass-derived furanic aldehydes to the corresponding cyclopentanones in water under a record-low H2 pressure and mild temperature.We unveiled a Co-catalysed bulk g-C3N4 decomposition/carbonisation CNTs formation mechanism.A new HR pathway was also unveiled.2.Catalytic hydrodeoxygenation(HDO)is one of the most important strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we reported for the first time of a simple synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultanted Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveiled that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirmed that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption and spillover of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work provides a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.3.The development of suitable and efficient wide-spectrum catalysts is crucial and will continue to be one of the major challenges for the advancement of innovative organic synthesis.Herein,we demonstrated an effective strategy to synthesize highly dispersed and highly loaded Co NPs catalyst via reducing Co-malonic acid(MA)precursor under a H2/Ar atmosphere.The as-synthesized Co-MA-280 as a wide-spectrum of catalyst can effectively hydrogenate a series of unsaturated compounds contain various functional groups,such as aldehydes,ketones,alkenes,N-heterocycles and nitro compounds in a low temperature and water solvent.Importantly,the catalyst can amplify the catalytic hydrogenation reaction of various compounds to gram-scale,and thus has great potential for industrial application.4.The earth-abundant transition metal hydroxides have been widely explored in oxygen evolution reaction(OER)because of their excellent redox abilities.However,for the selective HMF oxidation reaction(HOR),the OER is a major competitive reaction and thus the over-high OER activity will lead to a low conversion efficiency and faradaic efficiency.Herein,we synthsized a Ni(OH)2@SNMOFs composite material using Ni(OH)2 nanosheet arrays as precursor and template,which was further grown on NF and used as an electrode for high-efficiency HOR.The as-synthesized Ni(OH)2@SNMOFs/NF exhibited superior HOR performance,affording 100%FDCA yield with a faradaic efficiency of 100%at 1.4 V(vs.RHE)in 1.0 M KOH electrolyte.The presence of MOFs layers on the surface of Ni(OH)2 not only effectively suppresses the over-high OER activity of Ni(OH)2,but also facilitates the adsorption for HMF molecule via improved specific area and pore structure,thus dramatically enhancing the HOR performance.