On-Site Electrochemical Oxygen Reduction to Hydroxide and Hydrogen Peroxide for Sulfuryl Fluoride Solution Hydrolysis

Sulfuryl fluoride (SO 2 F 2 ) has been largely used as a postharvest fumigant replacing methyl bromide (widely recognized among ozone-depleting substances). Sulfuryl fluoride, however, is a potent greenhouse gas with a Global Warming Potential (GWP) of ~ 5000 for a 100-year time zone far higher than that of carbon dioxide and methane. Ongoing pilot work showed that SO 2 F 2 fumes vented from fumigation chambers can be captured and hydrolyzed by hydroxide (OH - ) and hydrogen peroxide (H 2 O 2 ) solution at pH ~12 in a scrubber with a complete conversion into SO 4 2- and F - as waste salts. The purchase, shipment, storage, and handling of concentrated stocks of H 2 O 2 and NaOH for use in SO 2 F 2 hydrolysis involve cost and safety concerns. Herein, we present an on-site, facile, and cost-effective pathway for the electrochemical production of OH - and H 2 O 2 in large enough concentrations to fully degrade ~ 95% of SO 2 F 2 captured. In that, we employed a commercial carbon catalyst that produced 250 mM H 2 O 2 at pH 12.6 within 4 h with a Faradaic efficiency of 98.8% for O 2 reduction to H 2 O 2 . We also propose a facile approach via surface oxidation of abundant carbon materials to significantly enhance both activity and selectivity for OH - and H 2 O 2 production under electrochemical oxygen reduction reaction. These findings provide new insights in the on-site production of industrial chemicals by means of clean, facile, and environmentally friendly electrochemical pathway. Moreover, the capability of recycling the hazardous SO 2 F 2 fumes and using the SO 4 2- and F - waste products as free sources of electrolyte can’t be overemphasized.