A new class of hydrophobic CuO nanosheets is introduced by functionalization of the cupric oxide surface with p-xylene, toluene, hexane, methylcyclohexane and chlorobenzene. The resulting nanosheets exhibit a wide range of hydrophobicities with contact angles ranging from 146° (p-xylene) to 27° (chlorobenzene). Significant changes to the surface composition induced by functionalization was verified by XPS, ATR-FTIR and computational modeling. UV-Vis DRS showed that functionalization with these molecules increase the band gap of the CuO nanosheets by 0.05-0.08eV. DFT and tight-binding calculations showed near identical increases of band gaps in modelled slabs of CuO with functional groups attached. Furthermore, TGA and H2-TPR show that the functional groups stabilize the CuO nanosheets, and that the stability is correlated with the hydrophobicity of the material.
