A Cosolvent Electrolyte Boosting H₂S Decomposition via Three-Phase Indirect Electrolysis

Renewable electricity-driven production of value-added sulfur and H₂ via electrocatalytic H₂S decomposition represents a sustainable route to conventional thermocatalysis. Both the electrocatalyst and electrolyte solution strongly impact the H₂S decomposition performance. Despite significant progress in developing sophisticated electrocatalysts, a well-designed electrolyte solution in conjunction with industrial catalysts is an attractive strategy to advance the industrialization process of electrocatalytic H₂S decomposition, but remains unexplored. Here, for the first time, we design a solid–liquid–gas three-phase indirect electrolysis system based on a kind of CS₂-N electrolyte solution and Ni-Mo₂C that can efficiently enable H₂S decomposition into valuable H₂ and sulfur. Specifically, the solid-phase Ni-Mo₂C as a heterogeneous redox mediator presents excellent electrocatalytic efficiency for the H₂S removal efficiency of up to 99%, and the formation of liquid-phase sulfur product (CS₂-N electrolyte solution dissolves sulfur, yield up to 95%) with the generation of gas-phase H₂ product (~1.32 mL min⁻¹), resulting in an interesting three-phase indirect electrolysis system. Remarkably, it enables the scale-up production (~6 g in a batch experiment) of sulfur with continuous operation for 120 h without attenuation. This work may inaugurate a new electrocatalytic H₂S decomposition avenue to explore porous metal materials and electrolyte systems in simultaneous production of value-added sulfur and H₂.