A theoretical study of novel Rh2P2 and their analogs for electrocatalytic hydrogen evolution reactions

Abstract

The hydrogen evolution reaction (HER) plays an important role in water splitting for hydrogen production. Exploring the origins of catalyst activity from a theoretical perspective and establishing descriptors that relate catalytic activity to ΔG_H∗ are crucial steps in the pursuit of efficient catalysts. Here, we propose a novel family of orthorhombic electrocatalytic materials, T₂X₂ (T = Rh, Pd, Ir; X = P, Ge, Sb), for HER, based on first-principles calculations. Our calculations show that Rh₂P₂ exhibits an overpotential (η = 0.061 V) and can serve as an efficient HER electrocatalyst, showing lower overpotential than Pt. By analyzing the linear relationship between the p-band center (ε_p) of various materials and ΔG_H∗, we reveal the key role of electronic properties in catalytic performance. The study reveals that the p-band center serves as a key descriptor for HER catalyst design, providing theoretical support at the electronic structure level for constructing efficient energy conversion materials.