Noncovalent functionalization of Ti3C2TX using cationic porphyrins with enhanced stability against oxidation

Ti3C2TX, as the most explored MXenes, are a rising star among 2D materials due to their astonishing physicochemical properties. However, their practical applications remain extremely challenging because of chemical degradation into TiO2 nanoparticles due to oxidation. Chemical functionalization is an effective way to improve their stability against oxidation and tune the physicochemical properties of 2D materials. In this paper, Ti3C2TX is noncovalently functionalized using two different cationic porphyrins and the two hybrids show good stabilities in water against oxidation. The electrostatic interactions between the cationic porphyrins and the Ti3C2TX nanosheets are confirmed by the changes in the zetapotential and the photophysical measurements. The hybrids show a red shifted Soret band of the porphyrins with a complete quenching of the fluorescence emission, which confirms the effective interactions and an energy/electron transfer between the porphyrins and the Ti3C2TX nanosheets. The exfoliated and functionalized Ti3C2TX are characterized using various microscopic and spectroscopic techniques. The two hybrids exhibit pH dependent release of cationic porphyrins particularly under acidic conditions. This study proposes a potentially useful strategy for the preparation of highly stable and functional MXenes towards promising applications in biomedicines, optoelectronics and sensors.