Heterogeneous catalysis is the most crucial technological advancement in the chemical industry, environmental and energy applications, etc. This chapter highlights recent developments in creating and using metal oxide/hydroxide catalytic nanoparticles for chemical processes such as hydrogen evolution reaction, Fischer–Tropsch process, oxygen evolution reaction, transesterification process and oxidation of volatile organic compounds to the reduction of NOx. These metal oxides have multiple redox states, tunable electronic structure and high electron conductivity, which enable them to act as catalysts and electrocatalysts for such catalysis processes. In this chapter, the classification of catalysis and synthesis of different nanostructures of metal oxides are also highlighted.