Twenty years after: scaling relations in oxygen electrocatalysis and beyond

Since the 2000s, so-called scaling relations have been recognised as a limiting factor in electrocatalysis. Overcoming these constraints is essential to advance energy conversion technologies such as electrolysers, fuel cells, and metal–air batteries. This review presents key concepts, tools, and manipulation strategies required to deal with the scaling relations in oxygen electrocatalysis, chosen as a representative case. Special attention is given to the catalyst's geometry as an emerging central variable in electrocatalysis – one whose influence is only beginning to be systematically understood. Building on geometric and chemical grounds, this review offers a structured tutorial for the theory-driven design of electrocatalysts the deliberate manipulation of scaling relations.