Sustainable Production of High-Purity Hydrogen by Sorption Enhanced Steam Reforming of Glycerol over CeO<sub>2</sub>-Promoted Ca<sub>9</sub>Al<sub>6</sub>O<sub>18</sub>–CaO/NiO Bifunctional Material
Bibliographic record
Abstract
The present work investigates the sustainable production of high-purity hydrogen through sorption enhanced steam reforming of glycerol (SESRG) over Ca 9 Al 6 O 18 –CaO/ x NiO ( x = 15, 20, and 25 wt %) and Ca 9 Al 6 O 18 –CaO/20NiO– y CeO 2 ( y = 5, 10, and 15 wt %) bifunctional catalyst-sorbent materials. A wet mixing method involving limestone acidification coupled with two-step calcination was employed to prepare the bifunctional materials. Cyclic carbonation/calcination tests revealed that the bifunctional materials promoted with 10 and 15 wt % of CeO 2 possessed an excellent CaO conversion (97% in both cases) and a remarkable cyclic stability (up to 15 cycles). This was mainly attributed to the thin shell-connected structure formed by the addition of CeO 2 and the oxygen mobility characteristic of CeO 2 . The use of Ca 9 Al 6 O 18 –CaO/ x NiO materials in five consecutive SESRG/regeneration cycles revealed that they suffered from fast deactivation mainly due to CaO sintering and coke deposition. Despite the high H 2 purity obtained (∼98%), the prebreakthrough time and hydrogen yield decreased significantly over five cycles. Interestingly, the addition of CeO 2 to the most efficient catalyst (Ca 9 Al 6 O 18 –CaO/20NiO) resulted in a significant improvement in material stability during cyclic operation. The performance of CeO 2 -promoted materials was shown to depend strongly on the CeO 2 content which controlled the number of adjacent Ni active sites, the amount of coke deposition, and the degree of CaO sintering. The bifunctional material promoted with 10 wt % of CeO 2 showed the best performance over five consecutive SESRG/regeneration cycles, with a stable H 2 purity of ∼98%, H 2 yield of ∼91%, and prebreakthrough time of 48 min. The long-term cyclic stability test of Ca 9 Al 6 O 18 –CaO/20NiO–10CeO 2 over 20 cycles exhibited a very stable performance with a H 2 yield of 91% and H 2 purity of 98% within 20 cycles, confirming the high potential of this material for SESRG process.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".