Enhancement effect of strong metal-support interaction (SMSI) on the catalytic activity of substituted-hydroxyapatite supported Au clusters

Cation- and anion-substituted hydroxyapatites (sHAPs) supported gold catalysts showed strong metal-support interaction (SMSI) under oxidative atmosphere. Mg- and Ce-substituted sHAPs stabilized Au clusters and imparted positively charged Au. The Au on these sHAPs became more positively charged upon formation of the oxidative SMSI. The catalytic activities for transvinylation of benzoic acid with vinyl acetate and isomerization of 3,4-diacetoxybut-1-ene (34DABE) correlated well with the cationic properties of Au; Au/Mg0.1SrHAP and Au/Ce0.1SrHAP with SMSI exhibited higher catalytic activity than other Au/sHAPs and the same catalysts without SMSI. The enhanced cationic properties of Au particles induced by oxidative SMSI surpassed the disadvantages of the reduction of the exposed surface Au atoms caused by SMSI. This work reveals that controlling the degree of SMSI is an efficient methodology to tune an optimal electronic state of metal NPs for target reactions and to provide highly active and durable catalysts.