Boosting CO₂ Hydrogenation to Methanol over Monolayer MoS₂ Nanotubes by Creating More Strained Basal Planes

The controlled creation, selective exposure, and activation of more basal planes while simultaneously minimizing the generation and exposure of edge sites are crucial for accelerating methanol synthesis from CO₂ hydrogenation over MoS₂ catalysts but remain a bottleneck. Here, we report a facile method to fabricate heteronanotube catalysts with single-layer MoS₂ coaxially encapsulating the carbon nanotubes (CNTs@MoS₂) through host-guest chemistry. Inheriting the long tubular structure of CNTs, the grown MoS₂ nanotubes exhibit significantly more basal planes than bulk MoS₂ crystals. More importantly, the tubular curvature not only promotes strain and sulfur vacancy (Sv) generation but also preferentially exposes more in-plane Sv while limiting edge Sv exposure, which is conducive to methanol synthesis. Both the strain and layer number of MoS₂ can be easily and finely adjusted by altering CNT diameter and quantity of precursors. Remarkably, CNTs@MoS₂ with monolayer MoS₂ and maximum strain displayed methanol selectivity of 78.1% and methanol space time yield of 1.6 g g_MoS^-1 h^-1 at 260 °C and GHSV of 24000 mL g_cat.^-1 h^-1, representing the best results to date among Mo-based catalysts. This study provides prospects for novel catalyst design by synthesizing coaxial tubular heterostructure to create additional catalytic sites and ultimately enhance conversion and selectivity.