Proaño Laura, Galefete Katlo, Rim Guanhe, Gusmão Gabriel, Jones Christopher W
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
ACS Sustain Chem Eng. 2025 Mar 21;13(12):4811-4822. doi: 10.1021/acssuschemeng.4c10562. eCollection 2025 Mar 31.
Reactive capture and conversion (RCC) explores the use of a single-unit process to capture CO and produce a product, in this case, methanol (MeOH). In this study, different configurations of a catalytic sorbent (CS) composed of ZnZrO catalyst and MgAlO sorbent with and without alkali modification are evaluated for CO adsorption, steady-state catalysis with cofed CO and H, and transient RCC performance. A catalyst composed of a physical mixture of MgAlO with ZnZrO resulted in a slight increase in CO uptake, with a low impact on the catalytic activity and RCC of the materials compared to ZnZrO alone. In contrast, Na impregnation significantly increased the level of CO uptake from 0.28 mmol/g (ZnZrO alone) to 0.6 and 1.1 mmol/g for the CS with Na on the catalyst or MgAlO , respectively. However, Na impregnation reduced the CO conversion rate and MeOH selectivity during steady-state cofeed experiments at 300 °C and 6 bar. In contrast to steady-state catalysis conditions, RCC, which is a cyclic capture and conversion process, creates dynamic CO and H surface coverages, favoring CH in the early stages of the conversion step and then CO and MeOH as the catalyst CO coverage reduces. The highest MeOH productivity during RCC was achieved with CS that balanced the CO uptake with only moderate catalyst rate reductions caused by Na addition. The optimal material, ZnZrO+10%Na/MgAlOx, achieved a CO uptake of 0.8 mmol/g and a MeOH productivity of 0.5 mmol/g with 100% selectivity at 260 °C and 6 bar during RCC. This marks the highest RCC MeOH productivity reported to date, although the process needs further optimization and even with optimization, may remain impractical. The results further demonstrate that optimization of catalytic sorbents under steady-state flow conditions does not easily correlate to transient capture and conversion cycles for methanol synthesis from CO.
反应性捕获与转化（RCC）探索使用单一单元工艺来捕获一氧化碳并生产一种产物，在本案例中为甲醇（MeOH）。在本研究中，对由ZnZrO催化剂和MgAlO吸附剂组成的催化吸附剂（CS）在有无碱改性的不同配置下进行了一氧化碳吸附、与共进料一氧化碳和氢气的稳态催化以及瞬态RCC性能评估。由MgAlO与ZnZrO的物理混合物组成的催化剂使一氧化碳吸收量略有增加，与单独的ZnZrO相比，对材料的催化活性和RCC影响较小。相比之下，钠浸渍显著提高了一氧化碳吸收水平，对于催化剂上有钠的CS或MgAlO，分别从0.28 mmol/g（单独的ZnZrO）提高到0.6 mmol/g和1.1 mmol/g。然而，在300°C和6巴的稳态共进料实验中，钠浸渍降低了一氧化碳转化率和甲醇选择性。与稳态催化条件相反，RCC是一个循环捕获和转化过程，会产生动态的一氧化碳和氢气表面覆盖度，在转化步骤的早期有利于生成甲烷，然后随着催化剂一氧化碳覆盖度降低，有利于生成一氧化碳和甲醇。在RCC过程中，通过平衡一氧化碳吸收与仅由钠添加导致的适度催化剂速率降低的CS实现了最高甲醇生产率。最佳材料ZnZrO + 10%Na/MgAlOx在260°C和6巴的RCC过程中实现了0.8 mmol/g的一氧化碳吸收量和0.5 mmol/g的甲醇生产率，选择性为100%。这是迄今为止报道的最高RCC甲醇生产率，尽管该工艺需要进一步优化，而且即使经过优化，可能仍然不实用。结果进一步表明，在稳态流动条件下对催化吸附剂的优化不易与从一氧化碳合成甲醇的瞬态捕获和转化循环相关联。
