Compressible and Recyclable Monolithic g-C(3)N(4)/Melamine Sponge: A Facile Ultrasonic-Coating Approach and Enhanced Visible-Light Photocatalytic Activity

Powdery photocatalysts seriously restrict their practical application due to the difficult recycle and low photocatalytic activity. In this work, a monolithic g-C(3)N(4)/melamine sponge (g-C(3)N(4)/MS) was successfully fabricated by a cost-effective ultrasonic-coating route, which is easy to achieve the uniform dispersion and firm loading of g-C(3)N(4) on MS skeleton. The monolithic g-C(3)N(4)/MS entirely inherits the porous structure of MS and results in a larger specific surface area (SSA) than its powdery counterpart. Benefit from this monolithic structure, g-C(3)N(4)/MS gains more exposed active sites, enhanced visible-light absorption and separation of photogenerated carriers, thus achieving noticeable photocatalytic activity on nitric oxide (NO) removal and CO(2) reduction. Specifically, NO removal ratio is as high as 78.6% which is 4.5 times higher than that of the powdery g-C(3)N(4), and yield rate of CO and CH(4) attains 7.48 and 3.93 μmol g(−1) h(−1). Importantly, the features of low-density, high porosity, good elasticity, and firmness, not only endow g-C(3)N(4)/MS with flexibility in various environmental applications, but also make it easy to recycle and stable for long-time application. Our work provides a feasible approach to fabricate novel monolithic photocatalysts with large-scale production and application.