Preparation Of Pb-Based Catalysts For Electrocatalytic Reduction Of Levulinic Acid To Valerate

With the diminishing of the fossil resources and the rapid increasing of the environmental problems,electrocatalytic conversion of biomass-derived platform molecules has received a widespread attention.Levulinic acid（LA）,As one of the important platform molecules derived from lignocellulosic biomass,can be used to synthesize many value-added chemicals,such as valeric acid（VA）,γ-valerolactone（GVL）,1,4-pentanediol,2-methyltetrahydrofuran,etc.Among these processess,one-pot synthesis of VA from LA is of great significance.Compared with thermocatalytic hydrogenation,electrocatalytic hydrogenation under ambient conditions is more promising.Design and optimization of the electrode materials can significantly improve the target product selectivity and Faradaic efficiency during the electrocatalytic hydrogenation.Metallic lead（Pb）has been reported to be the ideal non-precious metal cathode material with high selectivity of VA.Therefore,Pb-based electrodes with specific structures and compositions can be designed for the efficient and selective electrocatalytic reduction of LA to VA.In this paper,Pb-based materials were prepared by adding different types of surfactants and Pb-In composite materials were synthesized by hydrothermal method for the electrocatalytic hydrogenation of LA to VA.The details are as follows:1)Pb-based materials with different morphologies were synthesized by adding different types of surfactants in the preparation process and used for electrochemical reduction of LA.All the prepared materials were characterized and the corresponding electrochemical properties were analyzed.It was found that the electrochemical performance of all Pb-based catalysts prepared with the addition of surfactants was improved compared to the prepared without surfactant.Among the prepared Pb-based materials,CTAB-Pb material exhibited the best electrohchemical performance,with the VA selectivity of83.9%,the VA Faradaic efficiency of 90.2%,and the LA conversion of 32.4%.The addition of CTAB greatly changed the morphology and composition of the catalyst,giving more exposed active sites,and improved catalytic performance.Fuethermore,the prepared CTAB-Pb catalyst exhibited better stability.2)A series of non-noble metal Pb-In nanocomposites with different Pb-In molar ratios were prepared by a hydrothermal method.The prepared catalysts were characterized and electrochemical performance were tested.It is showed that the crystal phase,morphology and catalytic performance of the synthesized Pb-In composites were obviously affected the molar composition and calcination temperature during the preparation process.Among all Pb-In composites,the Pb₁-In₂-600 catalyst exhibited the best electrohchemical performance,which could be ascribed to the uniform sizes,low interfacial charge transfer resistance,large electrochemical surface area,and the synergistic effect between Pb and In metal of Pb₁-In₂-600.The LA conversion 41.4%,VA selectivity of 97.8%,VA Faradaic efficiency of 89.2%,and the current density of 134 m A cm^-2 could be obtained,which was higher than that reported in the previous literatures.