Comparative Study of Pd–Ni Bimetallic Catalysts Supported on UiO-66 and UiO-66-NH(2) in Selective 1,3-Butadiene Hydrogenation

Selective hydrogenation of 1,3-butadiene (BD) is regarded as the most promising route for removing BD from butene streams. Bimetallic Pd–Ni catalysts with changed Pd/Ni molar ratios and monometallic Pd catalysts were synthesized using two differently structured metal-organic framework supports: UiO-66 and UiO-66-NH(2). The effects of the structure of support and the molar ratio of Pd/Ni on the catalytic property of selective BD hydrogenation were studied. The Pd–Ni bimetallic supported catalysts, PdNi/UiO-66 (1:1) and PdNi/UiO-66-NH(2) (1:1), exhibited fine catalytic property at low temperature. Compared with UiO-66, UiO-66-NH(2) with a certain number of alkaline sites could reduce the catalytic activity for the BD hydrogenation reaction. However, the alkaline environment of UiO-66-NH(2) is helpful to improve the butene selectivity. PdNi/UiO-66-NH(2) (1:1) catalyst presented better stability than PdNi/UiO-66 (1:1) under the reaction conditions, caused by the strong interaction between the –NH(2) groups of UiO-66-NH(2) and PdNi NPs. Moreover, the PdNi/UiO-66-NH(2) (1:1) catalyst presented good reproducibility in the hydrogenation of BD. These findings afford a beneficial guidance for the design and preparation of efficient catalysts for selective BD hydrogenation.