Creation of a Highly Active Small Cu-Based Catalyst Derived from Copper Aluminium Layered Double Hydroxide Supported on α-Al O for Acceptorless Alcohol Dehydrogenation.

A highly dispersed carbonate-intercalated Cu -Al layered double hydroxide (CuAl LDH) was created on an unreactive α-Al O surface (CuAl LDH@α-Al O ) via a simple coprecipitation method of Cu and Al under alkaline conditions in the presence of α-Al O . A highly reducible CuO nanoparticles was generated, accompanied by the formation of CuAl O on the surface of α-Al O (CuAlO@α-Al O ) after calcination at 1073 K in air, as confirmed by powder X-ray diffraction (XRD) and Cu K-edge X-ray absorption near edge structure (XANES). The structural changes during the progressive heating process were monitored by using in-situ temperature-programmed synchrotron XRD (tp-SXRD). The layered structure of CuAl LDH@α-Al O completely disappeared at 473 K, and CuO or CuAl O phases began to appear at 823 K or 1023 K, respectively. Our synthesised CuAlO@α-Al O catalyst was highly active for the acceptorless dehydrogenation of benzylic, aliphatic, or cyclic aliphatic alcohols; the TON based on the amount of Cu increased to 163 from 3.3 of unsupported CuAlO catalyst in 1-phenylethanol dehydrogenation. The results suggested that Cu was obtained from the reduction of CuO in the catalyst matrix during the reaction without separate reduction procedure and acted as a catalytically active species.