Porous crystalline g-C3N4: Bifunctional NaHCO3 template-mediated synthesis and improved photocatalytic H2-evolution rate

Abstract To overcome the shortcomings of traditional gas-template method (which always causes a more disordered framework in the resulting porous g-C3N4 due to the thermal gas-flow shock from the template decomposition), in this study, we designed a new one-step template-mediated approach for the simultaneous realization of highly porous and ordered crystalline g-C3N4 photocatalyst, namely, bifunctional NaHCO3 template-mediated route. It was found that the NaHCO3 first works as the gaseous template to induce the formation of fluffy and porous prepolymerized dicyandiamide, while the produced Na2CO3 can further serve as the high-temperature solvent to promote the effective crystallization of the s-triazine structures, resulting in the production of porous and crystalline g-C3N4. Consequently, the resultant porous crystalline g-C3N4 presents a prominent increase for H2-generation rate, over two-fold larger than that of conventional bulk g-C3N4. The present bifunctional-template mediated approach may offer a novel technique for the construction of highly porous crystalline materials.