Enhanced photo-electrocatalytic performance of the nano heterostructures based on Pr³⁺ modified g-C₃N₄ and BiOI

Due to their superior optoelectronic characteristics and affordable cost, doped few-layered g-C₃N₄ (FCN) semiconductor nanostructures are attractive for photocatalytic and photoelectrochemical (PEC) water splitting applications. Nano heterostructures composed of Praseodymium (Pr)-doped few-layered graphitic carbon nitrides (FCN) and bismuth oxy iodide (BiOI) are manufactured using thermal condensation and hydrothermal technique in two steps. The inclusion of Pr dopant not only modifies the FCN by increasing its porosity and specific surface area, but also improves electron-hole separation and charge transfer. The metal-free nano heterostructure (Pr: FCN/BiOI) that was created exhibits a strong electron-hole separation. The observed rapid charge transit in a heterojunction results in a low rate of charge recombination. Thus, the produced metal-free nano heterostructure overcomes the barrier of FCN's high photo-charge carrier recombination rate. This study investigates the influence of Pr-doping on the structural, optical, electrical conductivity, and PEC characteristics of produced heterostructures. The addition of Pr dopant to FCN increases its ability to absorb solar light. The photocurrent density of the 1.5 wt percent Pr: FCN/BiOI nano heterostructure is 16.8 times greater than that of the 1.5 wt percent Pr: FCN nanostructure. In comparison to the other Pr-doping doses, it exhibits a high hydrogen evolution reaction (HER) photocurrent density (18.21 mA/cm²) and hydrogen evolution rate (3400 mol h⁻¹ cm⁻²) under solar light irradiation (420 nm). The current work gives significant insight into the optimization of composition and structural features for FCN photoelectrocatalysis with excellent performance.