A Cosolvent Electrolyte Boosting <scp> H ₂ S </scp> Decomposition via Three‐Phase Indirect Electrolysis

Renewable electricity‐driven production of value‐added sulfur and H 2 via electrocatalytic H 2 S decomposition represents a sustainable route to conventional thermocatalysis. Both the electrocatalyst and electrolyte solution strongly impact the H 2 S 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 H 2 S 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 CS 2 ‐N electrolyte solution and Ni‐Mo 2 C that can efficiently enable H 2 S decomposition into valuable H 2 and sulfur. Specifically, the solid‐phase Ni‐Mo 2 C as a heterogeneous redox mediator presents excellent electrocatalytic efficiency for the H 2 S removal efficiency of up to 99%, and the formation of liquid‐phase sulfur product (CS 2 ‐N electrolyte solution dissolves sulfur, yield up to 95%) with the generation of gas‐phase H 2 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 H 2 S decomposition avenue to explore porous metal materials and electrolyte systems in simultaneous production of value‐added sulfur and H 2 .