2D graphitic-C3N4 hybridized with 1D flux-grown Na-modified K2Ti6O13 nanobelts for enhanced simulated sunlight and visible-light photocatalytic performance

Two-dimensional (2D) graphitic-C3N4 (g-C3N4) was successfully hybridized with one-dimensional (1D) flux-grown Na-modified K2Ti6O13 nanobelts (Na-K2Ti6O13 NBs) for the first time to construct novel 1D/2D Na-K2Ti6O13/g-C3N4 heterostructured photocatalysts using a facile mixing-calcination method. The heterostructured Na-K2Ti6O13/g-C3N4 composites with three-dimensional (3D) hybrid architectures exhibited a remarkably enhanced photocatalytic efficiency for organic pollutant degradation in comparison with pure Na-K2Ti6O13 and g-C3N4 under both simulated sunlight and visible-light irradiation (lambda > 420 nm), which could be mainly attributed to the synergistic effects between Na-K2Ti6O13 and g-C3N4 including more efficient interfacial charge transfer, longer lifetimes and the stronger oxidation and reduction ability of photogenerated charge carriers, fundamentally originating from the formation of Na-K2Ti6O13/g-C3N4 heterojunctions based on the well-matched energy-band structures. Moreover, the Na-K2Ti6O13/g-C3N4 hybrids showed good stability and reusability for the photocatalytic degradation of organic pollutants. Finally, the possible mechanisms responsible for the improved simulated sunlight and visible-light photocatalytic performance were also investigated, respectively, based on the results of PL spectra, time-resolved fluorescence decay spectra, radical species trapping experiments, ESR spectra and PL-TA measurements. Overall, this work will not only be beneficial for the design and development of more efficient visible-lightresponsive g-C3N4-based composites for solar energy conversion and environmental remediation but will also be influential in optimizing the visible-light photocatalytic activity of wide-band-gap 1D titanate nanomaterials to meet the requirements of practical applications.