Highly enhanced ammonia decomposition in a bimodal catalytic membrane reactor for COx-free hydrogen production

Ammonia decomposition in a bimodal catalytic membrane reactor (BCMR) consisting of a Ru/γ-Al2O3/α-Al2O3 bimodal catalytic support and a hydrogen-selective silica membrane in a single unit was proposed for COx-free hydrogen production in the present study. The bimodal catalytic membrane showed a H2 permeance of 6.2 × 10-7 mol/(m2 s Pa) at 500 °C, with H2/NH3 and H2/N2 permeance ratios of 200 and 720, respectively. Ammonia conversion was surprisingly enhanced form 45 to 95% at 450 °C in the BCMR after selective H2 extraction. The BCMR showed excellent stability with respect to both gas permeation properties and catalytic activities.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The reactor consisted of a bimodal catalytic support and a silica membrane. ► The silica membrane showed a H2/NH3 permeance ratio of 200 at 500 °C. ► NH3 conversion was highly enhanced from 45 to 95% at 450 °C after H2 extraction. ► The membrane reactor showed excellent stability in a NH3 atmosphere.