Upgraded charge transport in g-C3N4 nanosheets by boron doping and their heterojunction with 3D CdIn2S4 for efficient photodegradation of azo dye

The facilitation of charge transport toward the targeted chemical reaction is a challenging task for two-dimensional (2D) nanomaterials. We demonstrate the effectiveness of two different strategies, non-metal doping and heterojunction formation, to adjust the electronic and molecular structures of g-C3N4 nanosheets (CN), which could widen the visible-light response and improve the photo-induced electron–hole separation. The g-C3N4 nanosheets containing impurity levels (boron doping (BCN)) were prepared by a high-temperature solid-state reaction. Additionally, by anchoring the 3D dichalcogenide structures (CdIn2S4) elicited by a wet chemical route, hybrid BCN/CdIn2S4 nanostructures were obtained. The resulting BCN/CdIn2S4 (BCN–CIS3) nanostructures exhibited an excellent degradation efficiency (95%) for methyl orange (MO) compared to pristine g-C3N4 nanosheets (CN) (28%) and boron-doped g-C3N4 (BCN) (35%). All the optimized photocatalysts were thoroughly characterized using various techniques and investigated for comparative structural, optical, morphological, and catalytic properties. Our results reveal that introducing boron atoms into the lattice of g-C3N4 nanosheets leads to reduction in the band-gap energy and rapid electron transfer. The formation of heterojunctions with the 3D CdIn2S4 further assists in improving the degradation efficiency by minimizing the undesired electron–hole recombination, as confirmed by time-resolved photoluminescence (TRPL) analysis. This work proposes feasible strategies and their synergy to develop innovative materials for sustainable energy conversion and environmental remediation applications.