RESUMEN
This work reports a new form of tubular g-C3 N4 that is featured with a hierarchical core-shell structure introduced with phosphorous elements and nitrogen vacancies. The core is self-arranged with randomly stacked g-C3 N4 ultra-thin nanosheets along the axial direction. This unique structure significantly benefits electron/hole separation and visible-light harvesting. A superior performance for the photodegradation of rhodamine B and tetracycline hydrochloride is demonstrated under low intensity visible light. This photocatalyst also exhibits an excellent hydrogen evolution rate (3631 µmol h-1 g-1 ) under visible light. Realizing this structure just requires the introduction of phytic acid into the solution of melamine and urea during hydrothermal treatment. In this complex system, phytic acid plays as the electron donor to stabilize melamine/cyanuric acid precursor via coordination interaction. Calcination at 550 °C directly renders the transformation of precursor into such hierarchical structure. This process is facile and shows the strong potential toward mass production for real applications.
RESUMEN
MXenes are the first class of 2D materials with the combination of metallic conductivity and hydrophilicity. However, degradation forms a key drawback limiting their long-term applications. This work for the first time demonstrates a strategy for designing a hydrophilic yet ultra-stable MXene via surface grafting with ionomers.
RESUMEN
MXene is an emerging class of 2D materials exfoliated from ternary carbide and nitride ceramics. The exfoliation process, which is an acid etching approach, functionalizes the MXene surface with -OH, -O and -F groups. These functional groups offer significant opportunities for tuning the colloidal properties of the MXene nanoblocks; importantly, this tunability points the way towards a facile route for assembling these nanoblocks into 3D architectures that are in demand for many applications. This route, presented for the first time here, uses water/oil interfaces for assembling Ti3C2-MXene in 3D architectures. It shows that cetyl trimethylammonium bromide (CTAB) can be used to tune the hydrophilic-hydrophobic balance of Ti3C2-MXene via the interaction of positively charged -N(CH3)3 and -O groups on the MXene surface. Crucially, it is found that this interaction can be controlled via the hydrogen ion concentration in the aqueous phase. Stable oil-in-water emulsions are the only product when the aqueous phase is neutral or basic. This understanding led us to fabricate a high internal phase Pickering emulsion with more than 70 vol% oil droplets and also a solid porous monolith based on this emulsion template.