Enhancement of Hydrogen Adsorption on Spray-Synthesized HKUST-1 via Lithium Doping and Defect Creation.

We prepared HKUST-1 (CuBTC; BTC = 1,3,5-benzenetricarboxylate) using a spray synthesis method with Li doping and defect created via partial replacement of HBTC with isophthalic acid (IP) to enhance the H adsorption capacity. Li-doping was performed by incorporating LiNO in HKUST-1 via spray synthesis and subsequent thermal treatment for decomposing NO, which enhances H uptake at 77 K and 1 bar per unit mass and per unit area from 2.37 wt% and 4.16 molecules/nm for undoped HKUST-1 to 2.47 wt% and 4.33 molecules/nm, respectively. Defect creation via the replacement of the BTC linker with the IP linker slightly in HKUST-1 skeleton did not affect H uptake. Both Li-doping and defect creation significantly enhanced H uptake to 3.03 wt%, which was caused by the coordination of Li ions with free carboxylic groups of the created defects via IP replacement.