Integrating a Dual Mode of Intrinsic Structural Modifications of g-C₃N₄ by K⁺ Ions and Amorphous Carbon for Efficient Photocatalytic H₂O₂ Production

Herein, a dual mode of intrinsic structural modifications of g-C3N4 has been designed by simultaneous incorporations of alkali metal K+ and amorphous carbon inside the 2D matrix of g-C3N4. Detailed structural and elemental investigations suggest that this typical dual mode of structural modifications promotes intraband defects, porosity, and active sites for photocatalysis. The optoelectronic features of the structurally modified g-C3N4 are further supported by the in-depth photophysical studies. Results suggest that visible light absorption increases along with efficient charge separation inside g-C3N4, upon simultaneous incorporation of K+ and amorphous carbon. Finally, this typical structurally modified g-C3N4 system has been utilized for photocatalytic H2O2 production. The maximum H2O2 production reaches up to 9000 μmol gcatalyst–1 h–1 with ∼30% apparent quantum efficiency. The mechanism of this highly efficient photocatalytic H2O2 production has been studied by investigating the intermediates and photoinduced active species through chemical scavenging and electron paramagnetic resonance spectroscopy. Results show the crucial role of photoinduced oxygen free radicals in photocatalytic H2O2 production. This high value of H2O2 production efficiency upon application of the dual mode of structural modifications of g-C3N4 systems has been further supported by detailed transient photocurrent studies and electrochemical impedance spectroscopy.