Pure hydrogen and sulfur production from H2S by an electrochemical approach using a NiCu–MoS2 catalyst

Abstract

An enormous amount of hydrogen sulfide (H₂S) exists in an industrial world primarily as an undesirable waste by-product of fossil fuel processing, including natural gas, petroleum, and coal gasification, entailing a greener strategy for its conversion into more beneficial products viz. hydrogen (H₂) and sulfur (S). Herein, we have formulated a cost-effective and mixed-phase (1T and 2H) micro-flower like NiCu–MoS₂ catalyst towards the anodic sulfide oxidation reaction (SOR) and cathodic H₂ production via electrolysis. The SOR was initiated at 0.21 V vs. RHE, which is 1.02 V inferior to the thermodynamical potential of the oxygen evolution reaction (OER), i.e. 1.23 V. Moreover, it maintains 98.1% H₂ faradaic efficiency with remarkable endurance up to 150 h. Importantly when a H₂S electrolyzer was fabricated with NiCu–MoS₂, only 0.7 V cell potential was adequate to yield profuse H₂ by H₂S splitting, which is practically unachievable for water splitting due to kinetic and energetic complexity.