Water Splitting on a Pt1/C3N4 Single Atom Catalyst: A Modeling Approach

In this work we present a computational study of the nature of a Single Atom Catalyst (SAC) consisting of a Pt1 atom anchored on a C3N4 support, and of its reactivity in the water splitting semi-reactions, the Hydrogen Evolution (HER) and Oxygen Evolution (OER) Reactions. The work is motivated by the intense research in designing catalytic materials for water splitting characterized by a low amount of noble metal species, maximization of active phase, and stability of the catalyst. C3N4-based SACs are promising candidates. The results indicate that the chemistry of a single atom is complex, as it can be anchored to the support in different ways resulting in a different stability. The reactivity of the most stable structure in HER and OER has been considered, finding that Pt1@C3N4 is more reactive than metallic platinum. Furthermore, unconventional but stable intermediates can form that differ from the intermediates usually found on extended catalytic surfaces. The work highlights the importance of considering the complex chemistry of SACs in view of the analogies existing with coordination chemistry compounds.