Cooperative adsorption performance of topological nodal surface fermions and excess electrons in a three-dimensional topological electride Ba₃CrN₃

Electrides and topological materials have individually been identified as promising candidates for use in electrochemical catalysis. Recently, the concept of topological electrides has emerged, where the topological fermions arise from the excess electrons characteristic of electrides, highlighting their potential in catalytic processes. In this work, we report that the topological electride Ba₃CrN₃, hosting nodal surface fermions near the Fermi level, exhibits excellent adsorption properties-a critical requirement for catalytic applications. The bands forming the nodal surface are predominantly derived from the excess electrons located at the corners of the Ba₃CrN₃ unit cell. Due to the extensive projection of the nodal surface onto the Fermi level, Ba₃CrN₃ demonstrates robust adsorption characteristics, even under external biaxial strain up to 6%. Moreover, by doping holes to neutralize excess electrons, its adsorption ability is suppressed, confirming that these excess electrons play a pivotal role in the adsorption process. Overall, we reveal that the exceptional adsorption properties stem from the interplay between its topological features and the presence of excess electrons, providing insights into its catalytic potential.