Confined NiRu Bimetallic Catalysts for the Hydrogenation of Dimethyl Terephthalate to Dimethyl Cyclohexane-1,4-dicarboxylate

The structure of the catalyst plays an important regulatory role in heterogeneous catalysis. Herein, we report the preparation of a novel NiRu bimetallic catalyst Ru/Ni/Ni(Al)O-x, confined by a weak crystalline Ni(Al)O-x matrix, by the reduction of an NiAIRu-layered double hydroxide (LDH) precursor in hydrogen atmosphere. Doping Ru3+ in LDH can facilitate the reduction of Ni2+ by hydrogen spillover and obviously decrease the size of Ni particles. The catalytic performance was evaluated by dimethyl terephthalate (DMT) hydrogenation to dimethyl cyclohexane-1,4-dicarboxylate (DMCD). The Ru/Ni/Ni(Al)O-x sample showed an enhanced catalytic activity with the conversion rate of DMT 99.3% and the selectivity of DMCD 93.2%. The reduction temperature can greatly affect the microstructure evolution and accordingly the catalytic performance. The synergistic effect of metal Ru and Ni is proposed to enhance the ability to activate H-2 and to adsorb DMT on the Ni(Al)O-x matrix.