Pulsed Electrolysis Prevents Sulfur Poisoning for Sustained Sulfide Valorization.

Hydrogen sulfide (H2S), a toxic byproduct generated from metallurgy, incineration, and natural gas purification, poses serious environmental and health risks. Current treatments (e.g., the Claus process) are energy-intensive and generate secondary waste. Electrochemical sulfide oxidation (SOR) offers an energy-efficient alternative for simultaneous H2S removal and recovery of high-purity hydrogen and sulfur, but its application is hindered by anode deactivation due to sulfur deposition. Here, we report a dynamic microenvironment engineering strategy using pulsed electrolysis (PE) to achieve sustainable SOR. Coupled with a Sc-doped NiFe-LDH electrocatalyst optimized for intermediate adsorptions, we achieve periodical modulation of metal-sulfur redox, enabling efficient sulfur release and active site regeneration. This synergy enables continuous H2S destruction and hydrogen production for over 500 h with a Coulombic efficiency of 99.8% and a low energy consumption of 2.19 kWh m-3. Furthermore, using bio-derived formic acid, the acidification process is capable of co-production high-purity sulfur (99.5%) and sodium formate. This integrated process, validated also with industrial syngas and seawater electrolyte, increases the overall profit by 121% to US$1,294.7 per tonne of hydrogen. Overall, this report demonstrates a circular and economically viable strategy for H2S treatment and resource recovery, which is also implacable to other electrochemical systems facing catalyst poisoning.