Zhou Shenghui, Ma Wenrui, Anjum Uzma, Kosari Mohammadreza, Xi Shibo, Kozlov Sergey M, Zeng Hua Chun
Department of Chemical and Biomolecular Engineering, College of Design and Engineering, National University of Singapore, Singapore, 119260, Singapore.
The Cambridge Centre for Advanced Research and Education in Singapore, 1 CREATE Way, Singapore, 138602, Singapore.
Nat Commun. 2023 Sep 21;14(1):5872. doi: 10.1038/s41467-023-41362-y.
In-plane sulfur vacancies (Sv) in molybdenum disulfide (MoS) were newly unveiled for CO hydrogenation to methanol, whereas edge Sv were found to facilitate methane formation. Thus, selective exposure and activation of basal plane is crucial for methanol synthesis. Here, we report a mesoporous silica-encapsulated MoS catalysts with fullerene-like structure and atomic copper (Cu/MoS@SiO). The main approach is based on a physically constrained topologic conversion of molybdenum dioxide (MoO) to MoS within silica. The spherical curvature enables the generation of strain and Sv in inert basal plane. More importantly, fullerene-like structure of few-layer MoS can selectively expose in-plane Sv and reduce the exposure of edge Sv. After promotion by atomic copper, the resultant Cu/MoS@SiO exhibits stable specific methanol yield of 6.11 mol mol h with methanol selectivity of 72.5% at 260 °C, much superior to its counterparts lacking the fullerene-like structure and copper decoration. The reaction mechanism and promoting role of copper are investigated by in-situ DRIFTS and in-situ XAS. Theoretical calculations demonstrate that the compressive strain facilitates Sv formation and CO hydrogenation, while tensile strain accelerates the regeneration of active sites, rationalizing the critical role of strain.
二硫化钼(MoS₂)中平面内的硫空位(Sv)在CO加氢制甲醇反应中被首次发现,而边缘Sv则被发现促进甲烷生成。因此,选择性暴露和活化基面对于甲醇合成至关重要。在此,我们报道了一种具有类富勒烯结构和原子铜的介孔二氧化硅封装的MoS₂催化剂(Cu/MoS₂@SiO₂)。主要方法基于二氧化硅内二氧化钼(MoO₂)到MoS₂的物理受限拓扑转化。球形曲率能够在惰性基面中产生应变和Sv。更重要的是,少层MoS₂的类富勒烯结构可以选择性地暴露平面内Sv并减少边缘Sv的暴露。经原子铜促进后,所得的Cu/MoS₂@SiO₂在260℃下表现出稳定的甲醇比产率为6.11 mol mol⁻¹ h⁻¹,甲醇选择性为72.5%,远优于缺乏类富勒烯结构和铜修饰的同类催化剂。通过原位漫反射红外傅里叶变换光谱(DRIFTS)和原位X射线吸收光谱(XAS)研究了铜的反应机理和促进作用。理论计算表明,压缩应变促进Sv形成和CO加氢,而拉伸应变加速活性位点的再生,从而解释了应变的关键作用。