2D van der Waals solids (vdW) have received attention for decades, due to their unique anisotropic mechanical character, making them useful in applications such as lubricants and pencils. But their anisotropy is not limited only to mechanical properties; rather it extends by default to all physical properties, making vdW solids interesting candidates for applications in fields as varied as catalysis and electronics. Here, we explore nanostructures of group V transition metal dichalcogenides (TMDs), a family of vdW solids, NbS2 and TaS2. We develop new vapor-phase bottom-up synthetic routes for nanosheet and nanotube variants. Furthermore, we discover their anisotropy-resulting self-optimizing behavior as hydrogen evolution catalysts, opening a new area of research
