Constructing bio-templated 3D porous microtubular C-doped g-C3N4 with tunable band structure and enhanced charge carrier separation by Mohamed, Mohamad Azuwa, Zain, M. F. M., Jeffery Minggu, Lorna, Kassim, Mohammad B., Saidina Amin, Nor Aishah, Salleh, W. N. W., Salehmin, Mohd. Nur Ikhmal, Md. Nasir, Mohd. Faizal, Mohd. Hir, Zul Adlan