Multifunctional Roles of Clathrate Hydrate Nanoreactors for CO 2 Reduction

In this study, we explore a possible platform for the CO 2 reduction (CO 2 R) in one of water's solid phases, namely clathrate hydrates (CHs), by ab initio molecular dynamics and well‐tempered metadynamics simulations with periodic boundary conditions. We found that the stacked H 2 O nanocages in CHs help to initialize CO 2 R by increasing the electron‐binding ability of CO 2 . The substantial CO 2 R processes are further influenced by the hydrogen bond networks in CHs. The first intermediate CO 2 − in this process can be stabilized through cage structure reorganization into the H‐bonded [CO 2 − ⋅⋅⋅H−OH cage ] complex. Further cooperative structural dynamics enables the complex to convert into a vital transient [CO 2 2− ⋅⋅⋅H−OH cage ] intermediate in a low‐barrier disproportionation‐like process. Such a highly reactive intermediate spontaneously triggers subsequent double proton transfer along its tethering H‐bonds, finally converting it into HCOOH. These hydrogen‐bonded nanoreactors feature multiple functions in facilitating CO 2 R such as confining, tethering, H‐bond catalyzing and proton pumping. Our findings have a general interest and extend the knowledge of CO 2 R into porous aqueous systems.