Solvent-free catalytic synthesis and optical properties of super-hard phase ultrafine carbon nitride nanowires with abundant surface active sites

Abstract

High-quality ultrafine α/β-carbon nitride (α/β-C₃N₄) nanowires have been fabricated through a novel hot melt reduction synthetic method using polyvinylchloride ([–C₂H₃Cl–]_n), ammonium chloride (NH₄Cl) and ferric oxide (Fe₂O₃) as raw materials. The purity, structure, morphology, crystallinity and surface state of the as-prepared samples were investigated by FSEM, TEM, HRTEM, SAED, XRD, EDX, FTIR and XPS. The nanowires presented good crystallinity with a length range of 1–4 μm and an average diameter of about 10 nm. Every nanowire possessed a high specific surface area and rough surface with abundant exposed atoms/prominences, indicating that the surface structure will facilitate further surface modification, functionalization and related applications. In addition, UV-vis diffuse reflectance and the corresponding photoluminescence (PL) spectra indicated that the nanowires have a wide band gap (4.38 eV) and obvious ultraviolet luminescence properties at the maximum emission peak of about 340 nm. A catalytic reaction mechanism and the growth model were also proposed to explain the formation process of the C₃N₄ nanowires.