Prepaeation And Properties Of Ni-based Metal From LDH/C Composite Precursor

Catalytic hydrogenation reactions have provided important methods fororganic synthesis. The main generation are product and water, withoutproduction of by-products. Given the increasingly stringent environmentalregulations, there is now a concerted move to benign alternatives and catalytichydrogenation is emerging as one of the most promising and progressive lowenergy/nondestructive technologies. Recently, scientists are seeking highactivity and selectivity of the catalyst in hydrogenation.Layered double hydroxides (LDHs) have many unique and excellentproperties. LDHS as catalysts material can ensure two advantage: First, thevariable active components content, so as to achieve the catalyst materialpreparation control requirements; second, laminate on the active component isuniformly arranged, so that after high temperature calcinations the activespecies can highly dispersed, which make for catalyst materials with regularstructure and high yield. In this paper, LDH as base material and combined with its advantages.On one hand, We prepared the catalyst active of metal cation on layer boardand change the layers of anion with the help catalytic element, get the catalystof new preparation methods. On the other hand, active component areuniformly distributed after the reduction roasting.which make for catalyst withregular structure and high yield. The catalyst materials were characterized byXRD、FT-IR、HTXRD、BET、TPR、XPS、HRTEM、EMAX and a seriesof conclusions are obtained.(1) In the preparation of nickel boron catalyst, we combined with LDHinterlayer anions with exchangeable characteristic. Promoter B wasintercalated to the Ni-Al LDH by coprecipitation, and using the hydrothermalmethod preparation of hydrotalcite coating carbon precursor (LDH-BO3/C).The reduction of the catalyst in N2atmosphere and the optimal reductiontemperature was500℃. The experiment results show that doped with a smallquantity of promoter B could further promote the dispersion of metallic nickeand improvement of the particle size of catalyst. Catalytic performance of thecatalyst show that the catalyst in HDC of chlorobenzene has superiorperformance, indicative of the Ni efficient utilization.(2) Promoter P was intercalated to the Ni-Al LDH by anion-exchangemethod, and using the hydrothermal method preparation of hydrotalcitecoating carbon precursor (LDH-PO4/C). The reaction temperature of600℃was appropriate for P-Ni catalyst in N2atmosphere. The results indicated that: the appropriate P content had a great influence on the morphology andstructure of Ni-based catalyst and promote catalytic performance in thehydrogenation of cinnamaldehyde. However, catalyst nanoparticles may formCore-shell structure in the presence of too high P content, which reducescatalytic performance.