Diffusion Monte Carlo study of hydrogen adsorption on silicon carbide nanotube

Hydrogen is one of the candidates for environmentally friendly energy carriers. Although it has a high energy density per unit weight, its volumetric energy density is rather low, making its compact storage difficult. This is rather important when storage volume is paramount, such as in automobile and aviation industries. Physisorption of hydrogen molecules on materials with high surface area to volume ratio like nanotubes is one of the strategies to increase this volumetric efficiency. Along with carbon nanotube (CNT) and boron nitride nanotube (BNNT), silicon carbide nanotube (SiCNT) is one of the candidate materials for this use. Although it has yet to be experimentally sythesized in single-walled form, larger silicon carbide nanotubes have shown promising gains compared to carbon nanotubes in terms of storage capacity and lack of sorption hysteresis. Theoretical studies points to a stronger binding energy and the existence of point charges naturally occurring on alternating Si-C surface. We present our initial Diffusion Monte Carlo (DMC) results of the adsorption of molecular hydrogen on single walled SiCNT surface. DMC is a stochastic method solving the many-body Schrödinger equation and has demonstrated accuracies below the Kcal/mol for a wide range of materials.