One approach to improving photocatalytic activity is through nitrogen doping. Nitrogen, with its higher electronegativity compared to carbon, introduces electron-rich sites in the structure of the material, which can alter its electronic properties . Nitrogen doping has been shown to enhance the light absorption capabilities of semiconductors, particularly in the visible light range . This is achieved through the creation of new energy levels within the material, which lowers the band gap, allowing for more efficient photon absorption. Additionally, nitrogen doping can modify the charge carrier dynamics, promoting charge separation and reducing recombination rates, which are crucial for improving the efficiency of photocatalysts in HER . These modifications ultimately contribute to a material's increased photocatalytic activity under visible light.