High-efficiency of novel hierarchical 3D macroporous g-C3N4 material on solar-driven photocatalytic water-splitting for hydrogen evolution.

The use of multi-pore nanostructured g-C 3 N 4 photocatalysts is an efficient approach to separate photogenerated charge carriers and increase visible light photocatalytic performance. Recent progress has yielded nanostructured material through hard templating, which limits potential applications. Integrating the 2D building block into multidimensional porous structures remains a significant challenge in scalable production. Herein, a novel technique based on P407 bubble clusters templating and fixation by freezing is described for the first time to fabricate a 3D opened-up macroporous g-C 3 N 4 nanostructures for photocatalytic H 2 evolution. Three-dimensional hierarchical nanostructures provide more contact active sites and synergistically promote the creation of heterogeneous catalytic interfaces. This feature is very useful for understanding the transfer path of photoinduced charges as well as the origins of the high charge separation efficiency in photocatalytic reactions, thus yielding a remarkable visible light-induced H 2 evolution rate of 4213.6 μmol h−1 g−1, which is nearly 5.6 times (716 μmol h−1 g−1) higher than that of lamellar bulk g-C 3 N 4. This newly developed approach offers a promising alternative to synthesize broad-spectral response 3D hierarchal g-C 3 N 4 nanostructures and can be extended to assemble other functional nanomaterials as building blocks into macroscopic configurations coupled with electronic modulation strategy simultaneously. [Display omitted] • Hierarchically 3DMCNs were synthesized by Poloxamer 407 bubble clusters as a porogen template. • 3DMCN nanostructures with unusual spatial electron transfer properties were systematically demonstrated. • Optical absorption and interfacial reaction active sites were discussed. • The origin of the much superior HER by unique 3DMCN was proposed. [ABSTRACT FROM AUTHOR]