Robust Photocatalytic H₂O₂ Production over Inverse Opal g‑C₃N₄ with Carbon Vacancy under Visible Light

In the field of green chemistry, producing hydrogen peroxide (H₂O₂) via photocatalysis could be a promising method for obtaining chemical feedstock during industrial and environmental processes. Herein, we simultaneously introduced inverse opal (IO) structure and carbon vacancies (CVs) into carbon nitride to improve H₂O₂ production by photocatalysis. Experimental results reveal that, after visible light irradiation for 2 h, IO carbon nitride (IO CN-Cv) shows a H₂O₂ generation value of 325.74 μM over 1.69, 2.13, and 1.84 times more than the H₂O₂ generation of bulk CN-Cvs (bulk carbon nitride with Cvs), bulk CN (bulk carbon nitride without Cvs), and nanosheet CN (carbon nitride nanosheet), respectively. On the one hand, the typical IO structure improves the efficiency of visible light absorption and simultaneously provides more surface area for the adsorption of molecular oxygen. Meanwhile, the introduction of Cvs improves the separation ability of carriers. This study offers a new idea for enhanced production of H₂O₂ using visible light with metal-free materials in the era of energy shortage.