Hydrogen Recovery\nfrom H<sub>2</sub>S Electrochemical\nOxidation: A DFT Study

Electrolysis of hydrogen sulfide (H<sub>2</sub>S) offers\na green\nand zero-emission process for producing hydrogen and treating pervasive\nand harmful H<sub>2</sub>S from oil and gas refineries. However, the\ndevelopment of such a technology requires an efficient and stable\ncatalyst. Herein, we investigate the mechanism of the electrochemical\nH<sub>2</sub>S oxidation reaction (H<sub>2</sub>SOR) over various\nmetal oxides and metal sulfides using DFT calculations. We demonstrate\nwhy RuO<sub>2</sub> has been widely reported as an active H<sub>2</sub>SOR catalyst. We also demonstrate that metal oxides are affected\nby sulfur poisoning and that their activity toward H<sub>2</sub>SOR\nis enhanced following sulfur coverage. By including surface coverage\nanalysis for S-intermediates, we identify TiO<sub>2</sub> as a promising\nand durable catalyst for H<sub>2</sub>SOR with a 0.49 V calculated\noverpotential. We also investigated the H<sub>2</sub>SOR activity\nof pristine and doped metal sulfides. We show that even though doping\nappears to reduce the overpotential needed to drive H<sub>2</sub>SOR,\nthe S-intermediates block the active sites and decrease the reactivity.\nThis research paves the way for the creation of more effective catalysts\nby providing a computational understanding of H<sub>2</sub>S electrolysis\nover various catalysts.