Multifunctional 2D porous g-C3N4 nanosheets hybridized with 3D hierarchical TiO2 microflowers for selective dye adsorption, antibiotic degradation and CO2 reduction

Abstract

Seeking effective strategy to design multifunctional materials for pollutant removal and solar fuel production is of great significance for solving the worldwide environment and energy problems. In this work, two-dimensional porous graphite-like carbon nitride (p-g-C3N4) nanosheets (NSs) decorated with three-dimensional (3D) hierachical TiO2 microflowers (MFs) were constructed through a facile acid hydrothermal route. 3D TiO2 MFs originating from K2Ti6O13 nanobelts were combined with p-g-C3N4 NSs via solid interfacial connections. By chemical exfoliation and etching, the surface area of g-C3N4 was significantly increased along with the formation of porous structures and C vacancies. Interestingly, the hydrothermally produced two-dimensional (2D) p-g-C3N4 NSs showed extraordinarily selective adsorption towards anionic methyl orange via strong electrostatic attraction. More importantly, such 3D/2D TiO2/p-g-C3N4 micro-nano heteroarchitectures exhibited remarkably improved visible-light photocatalytic properties for antibiotic degradation and CO2 reduction, mainly attributed to the enlarged surface areas and pore volumes, increased adsorption/active sites, improved light absorption and higher separation efficiency of photogenerated charge carriers. This one-pot synthesis method opens new possibilities for rational design of multifunctional g-C3N4-based photocatalysts towards environmental purification and solar energy conversion.