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Syngas to Olefins over a CrMnGa/SAPO-34 Bifunctional Catalyst: Effect of Cr and Cr/Mn Ratio
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2021-09-02 , DOI: 10.1021/acs.iecr.1c02150
Peng Zhang 1 , Fanhui Meng 1 , Langlang Yang 1 , Guinan Yang 1 , Xiaotong Liang 1 , Zhong Li 1
Affiliation  

Metal oxide in a bifunctional catalyst plays crucial roles in catalytic activity for syngas conversion to olefin (STO). Here, ternary co-precipitated CrMnGa oxides with various Cr/Mn ratios were prepared and combined with SAPO-34 for an STO reaction. By adjusting the Cr:Mn:Ga atomic ratio to 3:2:1, a high CO conversion (43.5%) with light olefin selectivity (87.0%, CO2 free) is achieved under the reaction conditions of 400 °C, 3.0 MPa, and 3000 mL·h–1·g–1. The increase in the Cr/Mn ratio facilitated the CrMnGa catalyst reduction and enhanced surface oxygen vacancies contents and H2 dissociation ability. The mechanism reveals that *CH3O species act as the reaction intermediate for the reaction of CO with the surface OH group and the subsequent hydrogenation. More importantly, the introduction of Cr enhanced the CO activation ability at high temperatures and thus provided a well temperature match for intermediate generation over CrMnGa oxide and further transformation into light olefin over SAPO-34. This study provides a strategy for rational design of highly active metal oxides, which could be used to combine with other zeolites for syngas conversion to high value-added chemicals.

中文翻译:

CrMnGa/SAPO-34 双功能催化剂上的合成气制烯烃:Cr 和 Cr/Mn 比的影响

双功能催化剂中的金属氧化物在合成气转化为烯烃 (STO) 的催化活性中起着至关重要的作用。在这里,制备了具有各种 Cr/Mn 比的三元共沉淀 CrMnGa 氧化物,并与 SAPO-34 结合用于 STO 反应。通过将 Cr:Mn:Ga 原子比调整为 3:2:1,在 400 °C、3.0 MPa 的反应条件下实现了高 CO 转化率(43.5%)和轻烯烃选择性(87.0%,不含CO 2) , 和 3000 mL·h –1 ·g –1。Cr/Mn比的增加促进了CrMnGa催化剂的还原并提高了表面氧空位含量和H 2解离能力。该机制表明*CH 3O 物种充当 CO 与表面 OH 基团反应和随后氢化的反应中间体。更重要的是,Cr的引入增强了CO在高温下的活化能力,从而为CrMnGa氧化物中间生成和SAPO-34上进一步转化为轻烯烃提供了良好的温度匹配。该研究为合理设计高活性金属氧化物提供了一种策略,可用于与其他沸石结合,将合成气转化为高附加值化学品。
更新日期:2021-09-15
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