Fig. 2: Proof-of-concept for oxidizing H2S using H2O2.
From: Electrochemical valorization of H2S in natural gas to sulfate under mild conditions
a Pourbaix diagram of SO42− and S production from H2S in its various forms (H2S, HS−, or S2−) on the SHE (standard hydrogen electrode) scale. The dashed lines represent the reduction reactions of H2O2-to-H2O and O2-to-H2O, respectively, suggesting the thermodynamical ability of H2O2 for deep H2S oxidation, as well as stronger oxidizing capability than O2. H2Scap conversion (left in b), productivity of various oxidation products (right in b), and SO42− selectivity (c) at different H2O2 concentrations (0, 0.05, 0.1, 0.5, and 1 wt%) in 0.1 M KOH, with feeding 5% H2S/Ar at a flow rate of 20 ml min−1 for 2 h. The error bars represent the standard deviation of three independent measurements. Variation in the content of S2−, S2O32−, SO32−, and SO42− over time at H2O2 concentrations of 0.08 wt% (d), 0.4 wt% (e), and 1 wt% (f) in 0.1 M KOH. The amounts of NaHS and H2O2 were fixed at 1 mmol and 5 mmol, respectively. g Reaction pathway of H2O2-mediated H2S stepwise oxidation reactions under alkaline conditions.
