Chapter 3. Metal Phosphides and Their Applications in Catalysis

Abstract

Transition metal phosphides represent an interesting class of catalytic materials applicable to a wide variety of important reactions associated with renewable and/or cleaner energy processes. The activity of transition metal phosphides has been reported by many researchers as higher than the activity of industrial catalysts for hydrodesulfurisation (HDS) and hydrodenitrogenation (HDN) reactions required in petroleum refineries. Transition metal phosphides have also been used as selective catalysts to deoxygenate various biomass-derived model compounds, where selective cleavage of the C–O functionalities present in biomass is desired while preserving the aromatic nature of the feedstock. Very recently, the literature involving the hydrogen evolution reaction (HER) using transition metal phosphides has proliferated, as phosphides have the ideal property of low overpotential compared to other classes of non-noble metal materials. More importantly, the ability to alter the properties of phosphides by including multiple metals is key to their versatility. For example, bimetallic phosphides have further increased reaction performance via increases in activity, product selectivity, and stability. In this chapter, the synthesis of monometallic and bimetallic phosphides and their corresponding catalytic applications are highlighted for the above-mentioned reactions.