The present work investigates the sustainable production of high-purity hydrogen through sorption enhanced steam reforming of glycerol (SESRG) over Ca₉Al₆O₁₈–CaO/xNiO (x = 15, 20, and 25 wt %) and Ca₉Al₆O₁₈–CaO/20NiO–yCeO₂ (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 CeO₂ 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 CeO₂ and the oxygen mobility characteristic of CeO₂. The use of Ca₉Al₆O₁₈–CaO/xNiO 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 H₂ purity obtained (∼98%), the prebreakthrough time and hydrogen yield decreased significantly over five cycles. Interestingly, the addition of CeO₂ to the most efficient catalyst (Ca₉Al₆O₁₈–CaO/20NiO) resulted in a significant improvement in material stability during cyclic operation. The performance of CeO₂-promoted materials was shown to depend strongly on the CeO₂ 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 CeO₂ showed the best performance over five consecutive SESRG/regeneration cycles, with a stable H₂ purity of ∼98%, H₂ yield of ∼91%, and prebreakthrough time of 48 min. The long-term cyclic stability test of Ca₉Al₆O₁₈–CaO/20NiO–10CeO₂ over 20 cycles exhibited a very stable performance with a H₂ yield of 91% and H₂ purity of 98% within 20 cycles, confirming the high potential of this material for SESRG process.

中文翻译：

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吸附作用下CeO ₂促进的Ca ₉ Al ₆ O ₁₈ –CaO / NiO双功能材料对甘油的蒸汽重整增强，从而可持续生产高纯氢

本工作研究了通过在Ca ₉ Al ₆ O ₁₈ –CaO / x NiO（x = 15、20和25 wt％）和Ca ₉ Al上吸附增强的甘油蒸汽重整（SESRG）来可持续生产高纯度氢的方法。₆ O ₁₈ –CaO / 20NiO– y CeO ₂（y = 5、10和15 wt％）双功能催化剂吸附材料。采用包括石灰石酸化和两步煅烧的湿法混合法制备双功能材料。循环碳酸化/煅烧测试表明，双功能材料可通过10和15 wt％的CeO ₂促进具有出色的CaO转化率（两种情况下均为97％）和出色的循环稳定性（最多15个循环）。这主要是归因于通过加入的CeO形成的薄壳-连接结构₂和铈的氧迁移率特性₂。在连续的五个SESRG /再生循环中使用Ca ₉ Al ₆ O ₁₈ –CaO / x NiO材料表明，它们主要由于CaO烧结和焦炭沉积而遭受快速失活的困扰。尽管获得了很高的H ₂纯度（约98％），但预突破时间和氢产率在五个循环中均显着下降。有趣的是，添加了CeO ₂最有效的催化剂（Ca ₉ Al ₆ O ₁₈ –CaO / 20NiO）的使用显着提高了循环操作过程中材料的稳定性。已表明，CeO ₂促进材料的性能在很大程度上取决于控制相邻Ni活性位点数量，焦炭沉积量和CaO烧结程度的CeO ₂含量。用10 wt％的CeO ₂促进的双功能材料在五个连续的SESRG /再生循环中表现出最佳性能，稳定的H ₂纯度约为98％，H ₂产率约为91％，预突破时间为48分钟。Ca ₉的长期循环稳定性测试在20个循环中，Al ₆ O ₁₈ –CaO / 20NiO–10CeO ₂表现出非常稳定的性能，在20个循环中H ₂产率为91％，H ₂纯度为98％，证实了该材料在SESRG工艺中的巨大潜力。