Tailoring the catalytic activity of electrodes with monolayer amounts of foreign metals

During the past decade, electrocatalysis has attracted significant attention primarily due to the increased interest in the development of new generations of devices for electrochemical energy conversion. This has resulted in a progress in both fundamental understanding of the complex electrocatalytic systems and in the development of efficient synthetic schemes to tailor the surface precisely at the atomic level. One of the viable concepts in electrocatalysis is to optimise the activity through the direct engineering of the properties of the topmost layers of the surface, where the reactions take place, with monolayer and sub-monolayer amounts of metals. This forms (bi)metallic systems where the electronic structure of the active sites is optimised using the interplay between the nature and position of the atoms of solute metals at the surface. In this review, we focus on recent theoretical and experimental achievements in designing efficient (bi)metallic electrocatalysts with selective positioning of foreign atoms to form a variety of active catalytic sites at the electrode surface. We summarize recent results published in the literature and outline challenges for computational and experimental electrocatalysis to engineer active and selective catalysts using atomic layers.