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    基于二维MoS2催化剂光热催化CO2加氢高选择性制备乙烷

    Highly selective production of ethane from CO2 hydrogenation using 2D MoS2 catalyst under photothermal catalysis

    • 摘要: 在全球气候治理与“双碳”目标的共同推动下,CO2催化转化研究倍受关注。近年来,光热催化作为一种新兴的催化技术,不仅能够提高太阳光利用率,还可以将光能转化为热能,提升催化反应温度,兼具光催化和热催化的优势,因此成为CO2加氢反应的研究热点之一。然而,目前光热催化CO2加氢反应依然面临着催化剂活性低、光热效率不高和产物选择性难以调变等瓶颈问题,并且传统催化剂其主要选择性产物为C1,C2+产物的生成涉及复杂的C—C耦合过程,需要克服较高的动力学势垒,从而使得传统催化剂对C2产物的选择性普遍偏低。因此开发具有高活性、高选择性及光热稳定性的催化剂是实现CO2定向转化为C2产物的关键。通过调控前驱体中硫源和钼源的质量比,采用水热法合成了由超薄纳米片自组装而成的三维花状微米球一系列MoS2催化剂。其中MoS2-1.5催化剂在1.2 W/cm2光照下对C2H6选择性达69.2%,产率达253.66 μmol/(g·h)。同时,结果证实:通过调控光照强度、延长光照时间,可有效提升CO2转化率与乙烷选择性;通过与热催化的对比,凸显了光热催化条件下具有更高CO2转化效率与产物选择性的显著优势。MoS2优异的稳定性展现了二维硫化物在碳链增长反应中的独特优势,为设计在温和条件下将二氧化碳转化为高附加值化学品的光热催化剂提供了新思路。

       

      Abstract: Under the combined push of global climate governance and the “dual-carbon” goal, research on CO2 catalytic conversion has attracted great attention. In recent years, photothermal catalysis, as an emerging catalytic technology, can not only enhance the utilization of solar energy but also convert light energy into heat, increasing the reaction temperature and combining the advantages of both photocatalysis and thermocatalysis. Therefore, it has become one of the research hotspots for CO2 hydrogenation reactions. However, photothermal catalytic CO2 hydrogenation still faces challenges such as low catalyst activity, limited photothermal efficiency, and difficulty in controlling product selectivity. Furthermore, the main selective products of traditional catalysts are C1 compounds, and the formation of C2+ products involves complex C—C coupling processes that require overcoming high kinetic barriers, resulting in generally low selectivity for C2 products by conventional catalysts. Therefore, developing catalysts with high activity, high selectivity and photothermal stability is the key to achieving the targeted conversion of CO2 into C2 products. A series of MoS2 catalysts composed of three-dimensional flower-like microspheres self-assembled from ultrathin nanosheets were synthesized by hydrothermal method through regulating the mass ratio of sulfur source and molybdenum source in the precursor. Among them, the MoS2-1.5 catalyst achieved a C2H6 selectivity of 69.2% and a production rate of 253.66 μmol/(g·h) under 1.2 W/cm2 light irradiation. Meanwhile, the research results confirmed that by regulating the light intensity and extending the light exposure time, the CO2 conversion rate and ethane selectivity could be effectively enhanced. Through comparison with thermal catalysis, the significant advantages of higher CO2 conversion efficiency and product selectivity under photothermal catalysis conditions were highlighted. The excellent stability of MoS2 demonstrated the unique advantages of two-dimensional sulfides in carbon chain growth reactions, providing a new idea for designing photothermal catalysts that can convert CO2 into high-value chemicals under mild conditions.

       

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