Highly Active and Water-Resistant Cu-Doped OMS-2 Catalysts for CO Oxidation: The Importance of the OMS-2 Synthesis Method and Cu Doping.
Highly Active and Water-Resistant Cu-Doped OMS-2 Catalysts for CO Oxidation: The Importance of the OMS-2 Synthesis Method and Cu Doping.
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DOI：
10.1021/acsami.3c14133
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发表时间：
2023-12
影响因子：
9.5
通讯作者：
Rong Zhang;Qi Chen;Yun-Tao Hu;Li Yang;Zhen Chen;Cunwen Wang;Yuan-Hang Qin
中科院分区：
文献类型：
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作者：
Rong Zhang;Qi Chen;Yun-Tao Hu;Li Yang;Zhen Chen;Cunwen Wang;Yuan-Hang Qin
多孔隐黑烷型锰氧化物（OMS-2）具有优异的氧化还原性能，是贵金属催化剂CO氧化的理想替代品，但其催化活性仍有待提高，特别是在有水存在的情况下。鉴于OMS-2在氧化反应中具有较强的结构-性能相关性，本文采用固相法（OMS-2S）、回流法（OMS-2R）和水热法（OMS-2H）合成了OMS-2，旨在通过调整合成参数来调整其粒度、形貌和结晶度，从而提高其CO氧化性能。表征表明，OMS-2S由于结晶度低、比表面积高、氧空位含量大、氧化还原性能好，在无水条件下具有最高的CO氧化活性，但有水的存在会大大降低其CO氧化活性。在OMS-2中掺入Cu不仅可以提高其CO氧化活性，还可以大大提高其耐水性。的Cu-doped OMS-2S∼4 wt %铜催化剂可以实现T90的49°C (1% / 10% O2 / N2和WHSV = 60000毫升·g - 1·h级),排名最低的报道T90值锰氧化物CO氧化催化剂,它可以保持近100%股份转换的5卷%用水超过50 h。原位漂移特性表明,良好的耐水性Cu-doped OMS-2S可以归因于显著抑制表面羟基的一代,因为铜掺杂。本工作证明了合成方法和Cu掺杂对测定OMS-2的CO氧化活性和耐水性的重要性，将为合成高活性和耐水性的CO氧化催化剂提供指导。
Porous cryptomelane-type Mn oxide (OMS-2) has an outstanding redox property, making it a highly desirable substitute for noble metal catalysts for CO oxidation, but its catalytic activity still needs to be improved, especially in the presence of water. Given the strong structure-performance correlation of OMS-2 for oxidation reactions, herein, OMS-2 is synthesized by solid state (OMS-2S), reflux (OMS-2R), and hydrothermal (OMS-2H) methods, aiming to improve its CO oxidation performance through manipulating synthesis parameters to tailor its particle size, morphology, and crystallinity. Characterization shows that OMS-2S has the highest CO oxidation activity in the absence of water due to its low crystallinity, high specific surface area, large oxygen vacancy content, and good redox property, but the presence of water can greatly reduce its CO oxidation activity. Doping Cu into an OMS-2 can not only improve its CO oxidation activity but also greatly improve its water tolerance. The Cu-doped OMS-2S catalyst with ∼4 wt % Cu can achieve a T90 of 49 °C (1% CO/10% O2/N2 and WHSV = 60,000 mL·g-1·h-1), ranking among the lowest reported T90 values for Mn oxide-based CO oxidation catalysts, and it can maintain nearly 100% CO conversion in the presence of 5 vol % water for over 50 h. In situ DRIFTs characterization indicates that the good water resistance of Cu-doped OMS-2S can be attributed to the significantly suppressed surface hydroxyl group generation because of Cu doping. This work demonstrates the importance of the synthesis method and Cu doping in determining the CO oxidation activity and water resistance of OMS-2 and will provide guidance for synthesizing highly active and water-resistant CO oxidation catalysts.