Potassium-Doped Borophane Nanosheets: A Multifunctional Platform for Reversible Hydrogen Storage and Metal-Free Hydrogen Transfer.

2D borophene has long been proposed as a promising hydrogen storage material, but experimental demonstrations remain limited to boron hydride sheets derived from MgB₂. Here, we report the synthesis of potassium-doped borophane (BH) nanosheets, which serve as a high-capacity, reversible hydrogen storage platform and metal-free reducing agent. Through selective hydride transfer, the BH sheet efficiently converted levulinic acid (LA) to γ-valerolactone (GVL) under mild reaction conditions. Density functional theory (DFT) predicts a theoretical hydrogen content of 4.2 wt.% for the potassium-doped BH sheet. Remarkably, the dehydrogenated BH sheets can be partially regenerated under 50 bar H₂, demonstrating reversible hydrogen storage. This work serves as an experimental validation for alkali-metal-modified borophanes acting as a multifunctional material for hydrogen storage and transfer, opening avenues for sustainable energy and other applications.