Design Of Nano-Pd-based Catalyst And Its Application In Catalytic Research For The Selective Hydrogenation Of Resorcinol

With the increasing energy consumption of traditional chemical industry,environmental pollution and low production efficiency emerge in an endless stream.For this reason,new catalytic chemical production has become a research hotspot.From the perspective of green development and sustainable development,catalysis plays an increasingly important role in chemistry.The development of new and efficient catalysts is of great significance for the production of chemicals and the healthy development of society.1,3-Cyclohexanedione is an important chemical platform compound,which has important uses in medicine,agriculture,fine chemical industry and other fields.The production of 1,3-cyclohexanedione on catalysts with high activity,selectivity,stability,and low cost under mild conditions remains a great challenge.This paper revolves around the selective catalytic hydrogenation of resorcinol over a Pd-based catalyst to prepare 1,3-cyclohexanedione.The research mainly focuses on the following aspects:(1)Preparation of alkali metal K,Na doped Pd/Ti O₂ catalyst for resorcinol hydrogenation.And by changing the preparation method,adjusting the reducing agent,and adjusting the reaction conditions,the best activity data were obtained.And through characterization,it is proved that the alkali metal can make Pd more strongly immobilized on the surface of the carrier,so that the Pd particles are deposited smaller,more active sites are exposed,and the catalytic performance is improved.(2)Pd clusters/nano-Ti O₂(denoted as Pd_c/T₈)were prepared by chemical deposition-precipitation method using small-sized nano-anatase Ti O₂(8 nm)as the carrier for this reaction.Due to the quantum confinement effect of the carrier,the low size and crystal defects of nano-Ti O₂ can highly disperse and anchor Pd,and deposit Pd sub-nanoclusters.The material exhibits high selectivity and stability compared to catalysts with large-sized supports.Characterization studies show that the size of the support modulates the morphology,size,and electronic structure of Pd,and ultimately improves the catalytic performance.(3)The electron transfer of the catalyst is further investigated,and the catalytic mechanism is analyzed experimentally and computationally.Excessive hydrogenation experiments on TOF values confirmed that the intrinsic activity of Pd_c/T₈ was improved and the selectivity of resorcinol was high during hydrogenation.Electron transfer at the material interface was further confirmed by DFT calculations,with metal-support electron interaction(EMSI).The adsorption energy of each step of the catalyst was then calculated.The catalyst has the modes of"coplanar adsorption"and"non-coplanar adsorption"to the substrate.Due to EMSI,Pd_c/T₈ causes the electronic effect of metal to produce non-coplanar adsorption to the substrate.The reaction is highly selective.