Designing Superatomic(Li/Na/K)-Al-Sc Cluster Catalystsfor Selective Electrochemical HER and NRR

Catalyst development is crucial for advancing sustainable energy conversion, particularly in key reactions, such as hydrogen evolution reaction (HER) and nitrogen reduction reaction (NRR), which are essential for green fuel alternatives. Metal nanocluster-based catalysts, with their high atomic utilization and selectivity, show great potential for generating H₂ and NH₃. However, the progress of HER electrocatalysis is hindered by the lack of cost-effective non-noble metal catalysts, while NRR encounters additional challenges due to its intricate multielectron transfer mechanisms. Furthermore, the competitive interplay between HER and NRR introduces obstacles to achieving selective catalytic efficiency. In this study, we employ density functional theory and <i>ab initio</i> molecular dynamics simulation to explore design strategies aimed at enhancing catalytic performance for selective electrochemical HER and NRR. Specifically, we focus on magic-sized superatomic clusters within the (Li/Na/K)-Al-Sc compositional space, which exhibit 40-electron stability, as anticipated by the nuclear shell model. Our study demonstrates that the optimal scandium concentration in subnanometer MAl_{13–<i>x</i>}Sc_<i>x</i> (M = Li, Na, K) clusters enhances catalytic efficiency for HER and NRR. The precise composition of MAl₉Sc₄ cluster efficiently buffers electrons/protons, enabling multielectron redox processes and enhancing NRR selectivity, while MAl₁₁Sc₂ and MAl₁₀Sc₃ favor HER. These insights highlight the promise of atomically engineered metal cluster electrocatalysts, suggesting a compositional threshold to optimize stability, activity, and selectivity.