Promoted Synergic Catalysis between Metal Ni and Acid–Base Sites toward Oxidant-Free Dehydrogenation of Alcohols

Abstract

In a number of heterogeneous catalysis processes, synergic catalysis of metal and acid–base sites of supports is of vital importance and remains a challenge to obtain largely improved catalytic performance. Herein, an acid–base-promoted Ni nanocatalyst supported on Ni/Al mixed metal oxide (denoted as Ni/NiAl-MMO) was prepared on the basis of the in situ structural topotactic transformation of NiAl-layered double hydroxide (NiAl-LDH) precursor. In situ studies including XRD, Raman, and EXAFS verify that the cubic NiO-like phase (Al3+-doped NiO species), with medium-strong acid–base sites (Niδ+–Oδ− pair), are well-distributed in the amorphous Al2O3 to form NiAl-MMO support. The concentration of Ni active site and acid–base sites can be simultaneously enhanced by precisely tuning the in situ structural topotactic transformation parameters of LDH precursor as revealed by CO pulse chemisorption, CO2-TPD, and NH3-TPD, so as to achieve a promoted synergic catalysis between metal Ni and acid–base sites. The resul...