Tailoring the morphology of poly (triazine imide) by chemical equilibrium towards enhanced photocatalytic overall water splitting

Abstract

Poly (triazine imide) generally obtained via ionothermal synthesis typically exhibits nanosheet or hexagonal prism aggregation. This study presents an innovative approach to modulate PTI morphology without the addition of structure-directing agents. By manipulating the volatilization rate of gaseous substances like ammonia, various PTI morphologies were achieved. The results indicate that adjusting chemical equilibrium conditions favors the formation of morphologies with higher surface energy, leading to increased specific surface area and morphological variations. Notably, these changes do not alter the crystal structure, elemental composition or band gap, but significantly impact the dynamics of photogenerated carriers. Additionally, this morphological transformation not only increase the surface active sites but also enhance the interfacial interaction between the cocatalyst and the PTI support. Among the morphologies, rod-like PTI exhibit superior photocatalytic performance, with hydrogen evolution and oxygen evolution of 506.8 μmol h^-1 g^-1 and of 234.0 μmol h^-1 g^-1, respectively, representing a 15.8-fold increase over the original sample. Furthermore, the manipulation of chemical equilibrium during polymerization offers new insights and potential for advancing crystalline carbon nitride-based photocatalyst.