Gold Catalysis: A Reflection on Where We are Now

Heterogeneous catalysis by gold is now a very well established research topic and several thousands of papers have appeared since the pioneering studies based on CO oxidation and acetylene hydrochlorination reactions in which, for the first time, supported gold catalysts were shown to be the best catalysts for these reactions. It is now widely recognised that gold either by itself or in combination with other metals is an excellent redox catalyst. In particular gold-containing catalysts are very effective for the selective oxidation of alcohols. Initially it was considered that base was needed to be present for alcohols to be effectively oxidised but efficient catalyst design has enabled alcohols to be oxidised to aldehydes without the need for added base. Gold-containing catalysts are also exceptionally effective for the hydrogenation of oxygen to form hydrogen peroxide. This direct synthesis route shows great potential for a number of applications at this time. More recently gold-containing catalysts have been shown to be effective in C-H activation reactions. Due to the ever increasing opportunities for applying heterogeneous gold catalysts, interest in how effective catalysts are designed and synthesised remains strong. In this paper both the early work and the more recent discoveries concerning heterogeneous catalysis by gold will be considered and some suggestions on the way forward will be presented.