Sulphur doped boron carbon nitride as novel metal free nanomaterials for photocatalytic degradation of organic pollutants and H₂ production

During microwave irradiation of the melamine-boric acid complex, boron/graphitic carbon nitride (BCN) has been successfully synthesized. Sulphur has been doped into a boron carbon nitride matrix by mechanical ball milling. Sulphur doped boron carbon nitride (SBCN) and boron carbon nitride (BCN), in addition to pure materials (i.e., g-C₃N₄ & h-BN) were vigorously analyzed to determine structural, morphological, and spectroscopical characteristics through XRD, FTIR, UV–vis DRS, XPS, TEM, and BET techniques. The photocatalytic activity of the materials was evaluated for the photodegradation of Methyl Violet (MV) under solar light. BCN showed enhancement in the photocatalytic activity degradation of MV in comparison to pure h-BN and g-C₃N₄. Introducing boron within CN framework has enhanced the electronic properties, the surface area, and suppressed charge recombination. A double band gap has been observed for BCN at 4.76 eV and 3.78 eV for B-N and C-N transition, respectively. The synergistic effect of CN and BN leads to efficient electron separation and transformation, hence improving photocatalytic activity. Moreover, upon doping with Sulphur, the photocatalytic degradation (MV) was enhanced up to 9.5 & 5.3 times compared to h-BN and g-C₃N₄, respectively. In addition, by Sulphur doping, the surface area has been increased up to > 3 times as compared to BCN, which may indicate the exfoliation of BCN sheets and the decrease of the planar size of BCN, that's confirmed by XRD and TEM. Moreover, Noble metal loaded SBCN showed good photocatalytic H₂ evolution with efficiency of 833 μmol h⁻¹ g⁻¹ and ¹766.7 μmol h⁻¹ g⁻¹ for Ag/SBCN and Pt/SBCN, respectively. This study introduces novel metal free photocatalysts with excellent recyclability as sustainable materials for the water remediation from organic pollutants and hydrogen (H₂) generation.