Schottky\nJunction-Driven\nPhotocatalytic Effect in\nBoron-Doped Diamond-Graphene Core–Shell Nanoarchitectures:\nAn sp<sup>3</sup>/sp<sup>2</sup> Framework for Environmental Remediation

Self-formation\nof boron-doped diamond (BDD)-multilayer\ngraphene\n(MLG) core–shell nanowalls (BDGNWs) via microwave plasma-enhanced\nchemical vapor deposition is systematically investigated. Here, the\nincorporation of nitrogen brings out the origin of MLG shells encapsulating\nthe diamond core, resulting in unique sp<sup>3</sup>/sp<sup>2</sup> hybridized frameworks. The evolution mechanism of the nanowall-like\nmorphology with the BDD-MLG core–shell composition is elucidated\nthrough a variety of spectroscopic studies. The photocatalytic performance\nof these core–shell nanowalls is examined by the deterioration\nof methylene blue (MB) and rhodamine B (RhB) dyes beneath low-power\nultraviolet (UV) light irradiation. Starting with 5 ppm dye solutions\nand employing BDGNWs as the photocatalyst, remarkable degradation\nefficiencies of 95% for MB within 100 min and 91% for RhB within 220\nmin are achieved. The effect of varying dye concentrations was also\nexamined. The enhanced photocatalytic activity is driven by carrier\nphotogeneration and mediated by the Schottky junction formed between\nBDD and MLG, promoting efficient photoinduced charge separation. The\nstability of the BDGNW photocatalyst is examined, and after five test\nruns, the photocatalytic behavior for MB and RhB degradation decreases\nto 87 and 85%, respectively, from initial values of 96 and 91%, demonstrating\nexcellent photostability. These findings underscore the significance\nof diamond-graphene nanoarchitectures as promising green carbonaceous\nphotocatalysts.