Covalent organic nanosheets (CONs) have emerged as functional two-dimensional materials for versatile applications. Although π-π stacking between layers, hydrolytic instability, possible restacking prevents their exfoliation on to few thin layered CONs from crystalline porous polymers. We anticipated rational designing of a structure by intrinsic ionic linker could be the solution to produce self-exfoliated CONs without external stimuli. In an attempt to address this issue, we have synthesized three self-exfoliated guanidinium halide based ionic covalent organic nanosheets (iCONs) with antimicrobial property. Self-exfoliation phenomenon has been supported by molecular dynamics (MD) simulation as well. Intrinsic ionic guanidinium unit plays the pivotal role for both self-exfoliation and antibacterial property against both Gram-positive and Gram-negative bacteria. Using such iCONs, we have devised a mixed matrix membrane which could be useful for antimicrobial coatings with plausible medical benefits.

The need for renewable energy focuses attention on hydrogen obtained by using sustainable and green methods. The sustainable compound glycerol can be used for hydrogen production by heterogeneous photocatalysis. A novel approach involves the promotion of the TiO2 photocatalyst with a binary combination of nitrogen and transition metal. We report the synthesis and spectroscopic characterization of the new N-M-TiO2 photocatalysts (M=none, Cr, Co, Ni, Cu), and the photocatalytic reforming of glycerol to hydrogen under ambient conditions and near-UV or visible light versus benchmark P25 TiO2 . In units of activity μmol m(-2)  h(-1) , N-Ni-TiO2 is five-fold more active than P25, and N-Cu-TiO2 is 44-fold more active. The photocatalytic activity of N-M-TiO2 increases from Cr to Co and Ni, whereas the photoluminescence decreases; the change in activity is due to the modulation of charge recombination.

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For the sustainable production of hydrogen by photocatalysis, the use of renewable resources such as water, organic compounds from plant biomass and earth abundant metal promoters is desired. We herein describe the previously not reported "one-pot" photoassisted synthesis of a binary metal-nitrogen promoted Cu(0)-N-TiO photocatalyst from a N-TiO precursor by photodeposition of copper directly in the photocatalytic suspension. The N-TiO contains nanocrystalline anatase as found by XRD and Raman spectroscopy. X-ray Photoelectron Spectroscopy (XPS) and Electron Spin Resonance (ESR) spectroscopy indicate that a nitrogen promoter is present as a substitutional site. The scheme of relaxation of a photoexcited charge through a substitutional nitrogen induced midgap states in N-TiO is proposed. The binary promoted Cu(0)-N-TiO photocatalyst prepared from N-TiO by "one-pot" photodeposition of copper in the suspension showed a high activity in the in situ hydrogen generation under near-UV/visible light with glycerol in water, up to 675 μmol g h. The "one-pot" photoassisted synthesis and mechanism of operation of the Cu(0)-N-TiO photocatalyst are studied by the complementary in situ spectroscopic methods.