Electrochemical valorization of H2S in natural gas to sulfate under mild conditions

H 2 S capture and valorization from polluted natural gas offer environmental and resource recovery benefits, but current approaches produce moderate-value sulfur with intensive carbon footprint. Herein, we develop an electrochemical deep oxidation method that converts H 2 S from polluted natural gas into value-added K 2 SO 4 using in-situ cathodically generated H 2 O 2 . We first validate this concept using commercial H 2 O 2 and then in-situ generated H 2 O 2 in H-cell, revealing the importance of high H 2 O 2 concentration for deep H 2 S oxidation, especially sluggish S 2 O 3 2− -to-SO 3 2− conversion. We then showcase its application potential in 4-cm 2 and then 100-cm 2 flow reactor with high interfacial H 2 O 2 concentration and large current, with the latter achieving H 2 S removal (100,000 ppm to <15 ppm), >70% K 2 SO 4 selectivity, and 100-h stable operation. Life-cycle assessment and techno-economic analysis confirm the strategy’s sustainability advantages and economic viability. We finally extend this method to produce a 1.4 wt% H 2 SO 4 solution by modifying the flow reactor with a solid-electrolyte type.