Alkali-Assisted Synthesis of Nitrogen Deficient Graphitic Carbon Nitride with Tunable Band Structures for Efficient Visible-Light-Driven Hydrogen Evolution

A facile synthetic strategy for nitrogen-deficient graphitic carbon nitride (g-C₃ N_x ) is established, involving a simple alkali-assisted thermal polymerization of urea, melamine, or thiourea. In situ introduced nitrogen vacancies significantly redshift the absorption edge of g-C₃ N_x , with the defect concentration depending on the alkali to nitrogen precursor ratio. The g-C₃ N_x products show superior visible-light photocatalytic performance compared to pristine g-C₃ N₄ .