Breaking the poisoning paradigm: a high-throughput DFT screening of high-entropy alloys with a focus on phonon-induced uncertainty

Abstract

Although surface poisoning is usually thought to deactivate electrocatalysis, this work illustrates its intentional application in promoting the hydrogen evolution reaction (HER) via a systematic high-throughput machine learning and density functional theory (DFT) exploration of high-entropy alloys (HEAs). Eleven transition metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au) were systematically explored in the M₁M₂M₃M₄M₅-HEA platforms to establish their thermodynamic stability, dynamic behaviors, and CO*-poisoning capability. CO*-poisoned surfaces surprisingly reduced the average HER overpotential to 0.33 V from 0.82 V for a clean surface. In particular, CO*-poisoned FeCoCuPdAu-HEA catalysts have an HER overpotential of 0.06 V, which is lower than that of the clean surface, which exhibits an HER overpotential of 0.18 V. Our density of states analysis indicates that orbital hybridization between CO and active sites modifies the stabilization of the H* intermediate. Our analysis indicates that the number of valence electrons of the intermediates and the d-orbital numbers and atomic radius of the metals are critical descriptors for Gibbs free energy predictions. Ab initio molecular dynamics (AIMD) calculations includes uncertainties (standard deviation ≈ 0.16 V) in overpotentials and a quantum coherence loss of below 10 femtoseconds due to phonon-induced energy fluctuations. The study presents a fundamental investigation on the poisoned surface of high-entropy electrocatalysts and introduces new concepts to consider the phonon-induced fluctuation in energy.