Oxygen reduction reaction on nanostructured Pt-based electrocatalysts: A review

Pt deposition/anchoring technique and nature of the support influence the oxygen reduction reaction (ORR) activity in low-temperature proton exchange membrane fuel cells. Surface distribution, morphology (particle shape and size) of the deposited Pt nanoparticles (NPs) and physicochemical properties contribute to the electrocatalytic activity and durability of the catalyst. Investigations over the past two decades lead to various metal and metal oxide-based supports, along with advanced nanocarbon materials as suitable candidates since they play a vital role in defining surface morphology, particle-size distribution, crystallinity and electronic structure of the deposited Pt catalyst. Moreover, such supports improve the ORR activity and stability of the electrocatalyst due to their stronger interaction with the deposited Pt NPs. Briefly, a well-controlled and selective deposition of Pt NPs and designing of an excellent corrosion-resistant support for a promising ORR catalyst has gained more attention. Many advanced strategies are developed for the fabrication of atomically precise nanostructured Pt catalysts. This review summarises recent developments in the electrochemical, photochemical and physical deposition techniques for Pt NPs on various supports and their effects on the physicochemical properties and electrocatalytic activity towards the ORR.