... Four typical kinds of crop seeds are studied as non-metallic bio-precursors to synthesize biogenic N-P-codoped TiO₂ (BNP-TiO₂). The as-prepared BNP-TiO₂ samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen-adsorption measurement and UV-Vis spectroscopy. The results show that BNP-TiO₂ possesses single anatase phase with mesopore structures, and nitr ...