A Microscopic approach to Understand Synergies in Electrocatalysis - Finanziamento dell’Unione Europea – NextGenerationEU – missione 4, componente 2, investimento 1.1.

Very often to change the status quo is necessary to break some rules. This is the spirit of MUSE, a high risk/high gain project that wants to make a breakthrough in electrocatalysis by breaking scaling relations in oxygen and hydrogen electrocatalysis. This will be achieved by exploiting synergistic effects at the nanoscale and carefully orchestrating the interactions between different active sites. In particular, MUSE will tackle the study of ultrathin films (low dimensional oxides, transition metal dichalcogenides, doped graphene) supported on metals, which are intriguing materials characterized by unconventional structures and electronic properties, where a variety of nanoscale phenomena such as electron tunneling or nanoconfinement are possible. These systems will be synthesized under ultra-high-vacuum conditions, and then decorated by multiple single atoms to obtain synergistic multifunctional systems. Theoretical considerations suggest that such systems should circumvent the typical limitations of single site catalysts of scaling relations and open the possibility of new reaction mechanisms, but on the other handhowever they are extremely complex and sensibly depending on multiple factors. Therefore, to effectively exploit their potential in electrocatalysis it is necessary to achieve a precise understanding of their structure, properties and mechanism ofsynergistic interactions. To reach these goals we propose to study model systems (i.e. ultrathin films designed with atomic scale precision on single crystals surfaces) using the reductionist approach of Surface Science. Moreover, in addition to standard state-of-the art methods, we will use a brand new technique developed by the research unit @University of Padova, the noise-analysis of the tunneling current in electrochemical scanning tunneling microscopy (Nat. Catal. 2021, 4, 850; Joule 2022, 6, 617). This is a quite unique operando technique that can provides a direct imaging of the catalytic sites down to atomic level, and through the noise analysis allows to evaluate in a quantitative way the electrocatalytic activity: it is even possible to obtain Tafel slope and Turn Over Number on single catalytic centres. By using such atomically resolved information, complemented by theoretical modelling performed by the research unit @University of Torino, MUSE aims at obtaining unprecedented insights into electrocatalytic phenomena, e.g. understanding reactions paths, identifying reliable reaction descriptors and connecting them to the physicochemical properties of the catalytic centres. Given this knowledge, it will be possible to rationally design a new generation of electrocatalysts that could be used in alkaline fuel cells and alkaline water electrolysers. Thence, MUSE has the potential to give a significant contribution to the two most fundamental applied technologies needed for the implementation of the new energy infrastructure of the hydrogen economy.