Interfacial sulfur anchoring in high-entropy metal sulfides for durable and accelerated oxygen evolution reaction

High-entropy metal sulfides (HEMs) demonstrate superior electrocatalytic activity over their metallic counterparts by leveraging sulfur-modulated electronic structures to optimize the adsorption energetics of oxygen evolution reaction (OER) intermediates. However, conventional high-temperature solid-state synthesis and wet-chemical strategies for multicomponent systems still suffer from active-species aggregation and weak metal-substrate interfacial bonding, limiting active-site exposure and undermining catalytic activity and durability. Herein, a sulfur-anchoring strategy based on a two-step transient high-temperature shock (THTS) process is developed. The thermal shock incorporates sulfur into carbonized wood (CW), generating sulfur-modified porous carbonized wood (PCW) that subsequently serves as a substrate for the in-situ formation of quinary (FeCoNiMnMo)S_x nanoparticles. This strategy provides synergistic physical and chemical anchoring through CW hierarchical pores and interfacial metal‑sulfur‑carbon (M-S-C) coordination, effectively suppressing elemental segregation and nanoparticle migration. The optimized catalyst exhibits an excellent overpotential of 184 mV at 10 mA cm², significantly outperforming commercial RuO₂, and maintains stable operation for over 105 h with negligible decay. Microstructural characterization and X-ray photoelectron spectroscopy (XPS) reveal strong interfacial coupling between HEM nanoparticles and the sulfur-modified CW substrate. Density functional theory (DFT) calculations show that sulfur-induced interfacial electronic modulation shifts the d-band center from 0.893 to 1.01 eV, lowering the free-energy barrier of the rate-determining *O → *OOH step from 2.75 to 2.58 eV, and thereby accelerating OER kinetics. This work demonstrates the effective synergistic role of sulfur modification and porous interfaces in tuning the charge transfer and adsorption energetics, providing new insights into interfacial engineering for high-performance high-entropy electrocatalysts for water splitting.