Exploiting the LDH Memory Effect in the Carbon Dioxide to Methanol Conversion

Abstract The conversion of carbon dioxide into platform chemicals such as methanol using copper‐zinc oxide‐alumina (CZA) catalysts is one of the most studied reactions of the past decade. A variety of materials has been tested as catalysts precursors for this reaction, including layered double hydroxides (LDHs). However, the memory effect property of these materials has yet to be fully exploited as a means to maximize their performance. Through successive reconstructions of CuZnAl and CuZnMgAl LDH in Cu(CH 3 COO) 2 aqueous solution, a family of catalysts is developed and thoroughly characterized by means of X‐ray diffraction, electron microscopy and photoelectron spectroscopy. The repeated cycles of calcination, followed by the reconstruction process, lead to the formation of heterostructures combining the recovered LDH structure with CuO nanoparticles (NPs) embedded within the LDH platelets. Each calcination‐reconstruction cycle leads to increasingly smaller and more monodisperse CuO NPs. Catalytic testing reveals the formation of Cu and ZnO NPs during the reductive activation of the LDH material, enabling a large Cu/ZnO interface. This Cu/ZnO synergy is promoted by the consecutive calcination‐reconstruction cycles, such that the third reconstruction of the parent LDH material nearly reaches the performance of the commercially available CZA catalyst.