Efficient Photocatalytic H₂O₂ Production Ability of a Novel Graphitic Carbon Nitride/Carbon Composites under Visible Light

Abstract

In the present work, using one‐step calcination of a mixture made of potassium hydroxide (KOH), melamine, and microplastics, this work prepares a novel graphitic carbon nitride/carbon (g‐C3N4/C) composite, which can be employed to photo‐catalytically produce hydrogen peroxide (H2O2) at a high rate up to 6.146 mmol g−1 h−1 under visible light irradiation. By analyzing the energy band structure of the catalyst, the production of H2O2 in this system consists of two single‐electron reactions. The modification of KOH makes abundant N‐vacancies caused by cyano‐groups in g‐C3N4, enhancing the electron absorption ability. Moreover, the introduction of graphitic carbon increases its specific surface area and porosity and improves the adsorption ability of O2. Simultaneously, their synergism reduces the g‐C3N4 band gap, making both the conduction‐band and valence‐band positions more negative, showing enhanced reduction ability, lowering the energy barrier for oxygen reduction, and greatly improving the photogeneration performance of H2O2.