CO2催化加氢制备高附加值化学品是缓解温室效应,实现人类社会可持续发展的关键技术之一。二维MoS2材料由于其特殊的层状结构和表面丰富可调的S缺陷位,在CO2活化与转化中被广泛关注,将MoS2催化剂用于CO2加氢的关键在于表面S空位的构建。为开发高效构建S空位工艺,以MoS2纳米片为基础,利用H2O2刻蚀法在其表面引入S空位,对比了H2O2刻蚀前后CO2在常压和高压下的反应性能。研究表明,H2O2刻蚀能显著提升S空位含量,且不会改变MoS2的晶相结构,也未影响S空位的化学性质,从而明显提升CO2催化加氢的转化率,但不影响产物分布。在常压条件下,S空位主要催化CO2解离加氢为CO,选择性达96%以上;而在高压(5MPa)低温(180℃)条件下能以较高的选择性(79%)催化CO2加氢为甲醇,升高反应温度会提升CO2转化率,但甲醇的选择性会显著降低,同时伴随甲烷的生成。本研究提供了一种简便高效的构造S空位的制备工艺,为MoS2催化剂的工业化应用提供一定的理论和技术支撑。

Catalytic hydrogenation of CO2 to valuable chemicals is one of the key technologies to relieve global warming and promote thesustainable development of human society. Two - dimensional MoS2 materials have emerged as promising catalysts for CO2 activationand conversion due to their unique layered structure and adjustable S vacancies sites, which is the key active center for CO2 hydrogenation.In order to develop an efficient process for S vacancy creation, building S vacancies on MoS2 nanosheet were used as the basis for introducing S vacan-cies on the surface using H2O2 etching method, and the reaction properties of CO2 at atmosphere and high pressure beforeand after H2O2 etching were compared. The results show that H2O2 etching can significantly enhance the content of S vacancies without changing the crystal structure of MoS2 or affecting the chemical properties of S vacancy sites, which significantly enhances the conversion rate of CO2 catalytic hydrogena-tion without affecting the product distribution. Specifically, the S vacancies catalyze CO2 dissociationto pro-duce CO at atmosphere pressure with selectivity higher than 96%, whereas they are able to catalyze the hy-drogenation of CO2 tothe methanol at high pressure of 5 MPa and 180 ℃ with high selectivity (79%). In-creasing the reaction temperature improves theCO2 conversion, but the selectivity of methanol will be signifi-cantly reduced, accompanied by the generation of methane. Briefly, thiswork demonstrates a simple and ef-fective method to create S vacancies on MoS2, providing theoretical and technical support for the industrial application of MoS2 catalysts.

0 引言

1 试验

   1.1 材料

   1.2 催化剂制备

   1.3 催化剂表征

   1.4 反应性能评价

2 试验结果与讨论

   2.1 催化剂的结构表征

   2.2 反应性能评价

3 结论