(584dl) Unlocking Switchable Reactivity of 2D Boride By Asymmetric Adsorption

The structural diversity of metal borides arises from boron’s polymorphism, spanning intermetallic to covalent frameworks. Their stability, electronic behavior, and catalytic properties are governed by boron content and coordination. This intrinsic tunability enables broad reactivity across bulk and low-dimensional metal borides.

In this study, we investigate the reactivity of a series of boron-enriched 2D metal boride (hexagonal sandwich structure). We found it to be primarily covalent and exhibit significant fluxionality in both geometry (corrugation) and electronic structure upon adsorbate binding. This prompt us to study a scenario where the 2D boride has asymmetric ligands on both sides, and the implication on adsorption energetics turns out to be huge, alternating the adsorption energy of key NRR intermediates by up to 1.6 eV. In other words, by controlling the adsorbate on one side of the 2D boride, the other side can be switched between underbinding and overbinding energetics, therefore enabling a dynamic catalytic system going beyond the limit of the activity volcano. This system may be achieved by pulses or oscillations in film-separated compartments, and a promising dynamic catalyst with vast design space.