Preparation Of Ni-In Intermetallic Compound Catalyst And Hydrogenation Of Furfural Platform Molecules

The growing demand for energy and bulk chemicals in contemporary society was rapidly depleting our limited fossil resources.Renewable biomass was used as a feedstock to produce oils and fine chemicals,which can significantly reduce the use of fossil energy.In this regard,furfural and its derivative 5-hydroxymethylfurfural,as one of the important biomass platform compounds,which can transform to produce a series of high value-added chemicals with broad application prospects.But the highly efficient catalytic conversion of furfural-like platform molecules into specific chemicals was a difficult area of research at present.Intermetallic compounds,as novel noble metal-like catalysts,exhibited excellent target product selectivity in many hydrogenation reactions.Therefore,in this paper,Ni-In intermetallic compounds were used as catalysts to investigate the effects of Ni/In ratio,metal-support interaction and support acidity and basicity on the hydrogenation conversion of furfural-like platform molecules.The efficient hydrogenation of furfural platform molecules was achieved by modifying the catalyst structure and optimizing the experimental conditions.The first part of the work was the Ni-In intermetallic compound catalyst for the synthesis of 2,5-dimethylfuran（DMF）by hydrogenation of 5-hydroxymethylfurfural（HMF）.A single-phase Ni₂In intermetallic compound（IMC）catalyst was prepared via one-step reduction using Ni-Mg-Al-In quaternary hydrotalcite（LDH）as a precursor.The Ni₂In/Mg O-Al₂O₃ catalyst exhibited high selectivity for DMF,with the highest DMF yield reaching 93.2%following the optimization of reaction conditions.Furthermore,the Ni₂In/Mg O-Al₂O₃ catalyst demonstrated excellent stability.The experimental results and characterization indicated that the efficient conversion of HMF to DMF was achieved through the synergistic catalysis of Ni₂In and acid-base sites.This research has laid a foundation for the development of IMC-support synergistic catalysts in biomass hydrogenation and hydrogenolysis.To further improve the Ni-In-catalyzed hydrogenation conversion activity,Ni In_0.2/Mg O-Al₂O₃ with Ni-Ni₂In double hydrogenation active sites was prepared by adjusting the Ni/In ratio based on the work in Part I.The XRD,TEM and STEM revealed the formation process of Ni-In intermetallic compounds in the catalyst.The reaction findings revealed that Ni In_0.2/Mg O-Al₂O₃ catalyst exhibited greater hydrogenation activity and furfuryl alcohol selectivity than Ni₂In and Ni catalysts,with the maximum furfuryl alcohol yield of up to 98.9%.DFT calculations and characterization results showed that Ni and Ni₂In were the active sites for the adsorption of H₂ and furfural,respectively,improving the catalyst hydrogenation activity.The previous two sections of the experiment demonstrated that the structure and composition of the metal active site and acid-base of the support had significant effects on the hydrogenation performance of the catalyst.Therefore,in the third part of work,the acid-base of the Ni-In catalyst was adjusted by tuning the content of Mg and Al in Ni-Mg-Al-In LDH,which was used to catalyze the conversion of HMF to 5-methyl-2-furanmethanol（MFA）.The reaction results showed that changing the Mg/Al ratio considerably influenced the selectivity of MFA.When Mg/Al ratio was 4,the yield of MFA reached 50.0%.