Constructing bio-templated 3D porous microtubular C-doped g-C3N4withtunable band structure and enhanced charge carrier separation

For the first time, the bio-templated porous microtubular C-doped (BTPMC) g-C₃N₄with tunable band structure was successfully prepared by simple thermal condensation approach using urea as precursors and kapok fibre which provides a dual function as a bio-templates and in-situ carbon dopant. Prior to the thermal condensation process, the impregnation strategies (i.e. direct wet and hydrothermal impregnation) of urea on the treated kapok fibre (t-KF) were compared to obtained well-constructed bio-templated porous microtubular C-doped g-C₃N₄. The details on a physicochemical characteristic of the fabricated samples were comprehensively analyze using X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), N₂ adsorption-desorption, Thermogravimetric (TGA), and UV–vis spectroscopy. Our finding indicated that the hydrothermal impregnation strategy resulted in well-constructed microtubular structure and more carbon substitution in sp²-hybridized nitrogen atoms of g-C₃N₄ as compared to the direct wet impregnation. Also, compared to pure g-C₃N₄, the fabricated BTPMC g-C₃N₄ exhibited extended photoresponse from the ultraviolet (UV) to visible and near-infrared regions and narrower bandgap. The bandgap easily tuned with the increased t-KF loading in urea precursor which responsible for in-situ carbon doping. Moreover, as compared to pristine g-C₃N_4, dramatic suppression of charge recombination of the BTPMC g-C₃N₄ was confirmed through photoluminescence, photocurrent response, and electrochemical impedance spectroscopy. The resultants BTPMC g-C₃N₄ possesses more stable structure, promoted charge separation, and suitable energy levels of conduction and valence bands for photocatalysis application.

1. Mohamed, M., M. Zain, M., Jeffery Minggu, L., Kassim, M., Saidina Amin, N., W. Salleh, W., Salehmin, M., Md Nasir, M. and Mohd Hir, Z. (2018). Constructing bio-templated 3D porous microtubular C-doped g-C 3 N 4 with tunable band structure and enhanced charge carrier separation. Applied Catalysis B: Environmental, 236, pp.265-279.

DOI : https://doi.org/10.1016/j.apcatb.2018.05.037