Role of Synthesis in Evolution of Catalyst: Bulk, Dispersed to Single Atom

Abstract

The quantity of information available on subject such as synthesis and catalysis is vast. However, it is significant to integrate both subjects and present a comprehensive article. The present chapter is a small contribution to acclaim the role of synthesis in the development of catalysis industry and research. Three main categories of catalysts that evolved over the years are bulk, dispersed or supported and single atom catalysts (SACs)—which is an ultimate possible form of the dispersed catalysts. With the advancement in research on synthetic techniques, the dream of dispersion of single atoms on support could be realized by managing the associated high surface energy, which is a chief obstacle causing agglomeration and migration of metal ions. SACs are promising catalysts with exceptionally high activity, selectivity and turn over number. The catalyst industry is heavily dependent on bulk and dispersed catalysts, while SAC is at research stage. This chapter aims to give a brief account of all three classes and synthetic methods used to prepare industrial catalysts. It also gives an overview of novel/modified methodologies used to prepare nanoparticles of mixed metal bulk oxides and supported catalysts at large scale. Atomic layer deposition, wet chemical co-precipitation route, photo-deposition and atom trapping are four different approaches adopted to synthesize SACs are also discussed. Finally, it emphasizes synthesis–activity correlations by using examples from our laboratory on thermal reactions ranging from low-temperature CO oxidation, CO + N2O to high-temperature sulfuric acid decomposition catalytic reactions.KeywordsSynthesisBulk oxidesDispersedSingle atom catalystCO + N2OSulfuric acid decomposition