Catalytic Conversion of H <sub>2</sub> S to H <sub>2</sub> : Challenges and Catalyst Limitations
Hassan Aljama, Zainab Alaithan, Ali Almofleh
Abstract
H 2 S, a highly toxic chemical, is produced in massive quantities worldwide as a byproduct. Environmental regulations require >99% sulfur recovery, which is currently met using sulfur recovery units based on the Claus process, where H 2 S is converted to sulfur and water. Ideally, hydrogen in H 2 S is recovered as H 2 . Despite much effort to achieve this objective, especially in thermal catalysis, an industrial application remains distant. A fundamental factor is the lack of an effective catalyst. In this work, we employ density functional theory to illustrate the main limitations in existing catalysts. We use pure metals to explain this by studying the full elementary steps in H 2 S decomposition. We find that many catalysts, though capable of decomposing H 2 S, are limited due to sulfur poisoning. We conclude by outlining the ideal properties of a catalyst for this process.