SBA-15 assisted preparation of mesoporous g-C3N4 for photocatalytic H2 production and Au3+ fluorescence sensing

In the present work, we report the preparation of mesoporous graphitic-like carbon nitride (mpg-C3N4) using SBA-15 as hard template agent. The mpg-C3N4 exhibited a hypsochromic shift in the UV-vis absorption profile probably due to a lower degree of condensation of the tris-s-triazine units in its conjugate aromatic system. In addition, the mesoporous material demonstrated enhanced textural properties with a surface area estimated in 49.8 m(2)/g, which is one order of magnitude higher than the surface area of the bulk g-C3N4 sample. In this sense, the mpg-C3N4 shows a higher photocatalytic performance in the production of H-2 through the water splitting process. Furthermore, the mpg-C3N4 was also used as fluorescent probe for the sensitive detection of Au3+ ions in aqueous solution. The fluorescence quenching was quantitatively analyzed by the Stern-Volmer equation using the evolution of the photoluminescence (PL) emission at 371 nm (lambda(exc) = 250 nm). The limit of detection (LOD) was estimated at 1.1 mu M, which was lower than the estimated LOD using the bulk g-C3N4 sample (2.1 mu M). To the best of our knowledge, this work reports for the first time the detection of Au3+ ions through fluorescence quenching using g-C3N4 samples with different textural properties.