Dynamic single-atom catalysts on gallium to overcome the scaling relationship limit: AIMD screening for CO₂ reduction and hydrogen evolution reactions.

Abstract

Extensive research has been conducted on single-atom catalysts (SACs) for a range of electrochemical reactions. However, <i>static</i> SACs suffer from scaling relationship limits, which hinder their further development. In this work, we introduce the idea of <i>dynamic</i> SACs supported on Gallium for the hydrogen evolution reaction (HER) and the CO₂ reduction reaction (CO₂RR). We utilized AIMD and DFT calculations to systematically conduct high-throughput screening on s-, p-, d-, and f-block elements supported by Gallium denoted as M-SAC@Ga. We found that among all the understudied catalysts, Re-, Pt-, Pd-, Rh-, Ir-, Au-, Ag-, Ru-, Tc-, Ni-, Cu-, Os-, Hg-, and Ge-SAC@Ga possess thermodynamic and electrochemical stabilities. In addition: Ni-SAC@Ga leads to CO₂RR overpotentials of 0.28, 0.28, 0.69, and 0.92 V, respectively, toward CHOOH, CO, CH₃OH, and CH₄ formation. Low overpotentials and mitigation of scaling relationship limits are primarily due to the atomic intelligence (the ability to guide reactions) and dynamic coordination changes of SACs, seen through DFT and AIMD calculations. Analyzing the phonon-induced fluctuations in total energies suggests a standard deviation of up to 0.26 V in the calculated overpotentials. Additionally, the dephasing time for these dynamic systems is below 5 fs, a crucial factor affecting the modeling of catalytic behavior. Feature importance analysis suggests that the d-electron numbers serve as the universal descriptors for these catalysts. This study offers a comprehensive insight into the discovery of cutting-edge electrocatalysts and beyond by applying the concept of <i>dynamic</i> SACs.