Mo-Doped FeS Mediated H2 Production from H2S via an In Situ Cyclic Sulfur Looping Scheme

Decomposition of H2S into sulfur and clean fuel H-2 is an attractive process and requires a design concept with a maximum H2S conversion and a minimal energy consumption. Herein, we demonstrate a sulfur looping scheme in a one-reactor system using a low-cost and environmentally safe iron-based sulfur carrier. H2S decomposition is split into cyclic sulfidation and regeneration of sulfur carriers, which overcomes the inherent thermodynamic constraint, allowing in situ H-2 generation. We experimentally obtained 24% higher sulfur uptake in 2% Mo-doped iron-based sulfur carriers compared with undoped sulfur carriers. The reaction mechanisms unveiled by the density functional theory indicate that surface hydrogen diffusion is the rate-determining step for sulfidation of the sulfur carrier. Compared with the undoped sulfur carrier, Mo dopant facilitates the surface hydrogen diffusion, thus promoting the overall H2S conversion. This work demonstrates a novel strategy for high-yielding H2S removal through low-percentage dopant modification sulfur carrier and provides new insights for an effective dopant screening strategy aiding the future carrier design.