Isomorphic Insertion of Ce(III)/Ce(IV) Centers into Layered Double Hydroxide as a Heterogeneous Multifunctional Catalyst for Efficient Meerwein–Ponndorf–Verley Reduction

The development of highly active acid-base catalysts for transfer hydrogenations of biomass derived carbonyl compounds is a new, pressing challenge. Solid Frustrated Lewis Pairs (FLP) catalysis is possibly a solution but the development of this concept is still at a very early stage. Herein, by inserting Ce(III)/Ce(IV) centers into layered double hydroxide (MgAlCe–LDH), effective, selective and recyclable solid acid-base catalysts were synthesized, which enabled efficient transfer hydrogenation (MPV reduction) of biomass derived carbonyl compounds to corresponding alcohols. The cooperative, FLP-like interplay between the active sites of Ce(III)/Ce(IV) and the aluminum-containing defect sites formed by the incorporation of cerium into the lattice of LDH is necessary to maximize the catalytic efficiency. Furthermore, the crucial role of the surface hydroxyl groups in the MPV reactions and the negative impact of the interlamellar/adsorbed water molecules on the catalytic activity of MgAlCe-LDH were demonstrated. These solid FLP-like acid-base catalysts exhibited excellent catalytic performance (cyclohexanol yield of 45%; furfuryl alcohol yield of 51%), which is competitive or superior to the benchmark, Sn- and Zr-containing zeolite catalysts, under mild reaction conditions, especially low temperature (T = 65°C in the case of cyclohexanol production). Our research has indicated that Ce-containing LDH is a potentially commercial solid FLP catalysts