Directional electron/ion flux at crystalline-amorphous CoS2-MnOx heterointerface boosts water and seawater oxidation electrocatalysis

Crystalline-amorphous CoS 2 -MnO x constructed via deposition-order regulation. • Amorphous MnO x underlayer transports electron and ion flux to electrode surface. • Optimized d-band center on crystalline CoS 2 promoting OER kinetics in seawater. • Electron-enriched surface and dissolved manganate species repelling chloride ions. • Conventional crystalline-on-crystalline anti-chloride overlayer dilemma overcomed. Conventional crystalline-on-crystalline anti-chloride overlayer structures for seawater oxidation electrocatalysis suffer from physical shielding of active sites and limited functional tunability due to lattice constraints. Herein, a crystalline-amorphous CoS 2 -MnO x heterostructure is constructed on graphite felt via a sequential electrodeposition-hydrothermal route, with deposition order mediating precise interface regulation. The as-prepared structure exhibits superior electrocatalytic performance for alkaline seawater oxidation, demanding low overpotentials of 170, 308, and 392 mV to achieve current densities of 10, 100, and 500 mA cm −2 , respectively, together with robust stability. Experimental investigation and theoretical calculation reveal that the heterostructure triggers electron transfer from MnO x to CoS 2 , generating a built-in electric field with interfacial charge redistribution. This modulates the d-band center and accelerates oxygen evolution kinetics. Meanwhile, surface electron enrichment synergizes with released manganate ions to effectively repel chloride ions from approaching and adsorbing. Such directional electron and ion fluxes endow the catalyst with excellent chloride-resisting and oxygen evolution performances in seawater electrolysis. This work demonstrates a facile strategy for constructing crystalline-amorphous heterostructures and elucidates the interfacial engineering mechanism for enhanced seawater oxidation, offering a promising new paradigm for advanced electrocatalysts in green hydrogen industry. To address the dilemma of conventional crystalline-on-crystalline anti-chloride overlayer structures for seawater oxidation, a crystalline-amorphous CoS 2 -MnO x heterostructure is fabricated via precise deposition-order regulation. The amorphous MnO x underlayer not only exposes abundant active CoS 2 sites but also transports electron and ion flux to the surface for OER promotion and Cl − repulsion, establishing a novel and promising paradigm for durable seawater electrocatalysis. Download: Download high-res image (193KB) Download: Download full-size image