The direct reaction of KPHI with alkylchlorosilanes or HMDS did not result in formation of hydrophobic materials since polymeric carbon nitrides are known to be notoriously unreactive and difficult to modify. Therefore, KPHI was first modified by sol-gel deposited silica that served as a platform for attachment of hydrophobic moieties. The success of this hydrophobization procedure is demonstrated in Figure , where a water droplet in contact with the hydrophobized materials exhibits large contact angles, whereby hydrophilic KPHI and KPHI-Si films show complete wetting (Table ).