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• Heterostructure formed between Melem and g-C 3 N 4 suppress the electron-hole rebombination. • The composite material of g-C 3 N 4 /melem by molecular engineering strategy is prepared. • The photocatalytic efficiency of g-C 3 N 4 /melem was twice as high as that of pristine g-C 3 N 4. The low efficiency of photogenerated charge separation is a critical factor to restrict the efficiency of photocatalytic reaction. Extensive research efforts have been devoted to charging kinetics to improve the efficiency of photogenerated charge separation and transfer to catalytic sites. In this research, the heterostructure and interfacial electron polarization are formed between melem and graphitic carbon nitride (g-C 3 N 4) through first-principles calculation, which can greatly suppress the electron-hole recombination. The synergistic advantage of g-C 3 N 4 /melem hybrid reveals great enhancement in photocatalytic hydrogen activity. Subsequently, we prepared the composite material of g-C 3 N 4 /melem by molecular engineering strategy, and found that the photocatalytic efficiency of g-C 3 N 4 /melem was twice of pristine g-C 3 N 4. This study provides an insightful idea to improve the efficiency of photogenerated charge separation. [ABSTRACT FROM AUTHOR]

Abstract Graphic carbon nitride (g-C 3 N 4) is a kind of promising organic semiconductor in visible light driven photocatalysis due to its metal free, high physicochemical stability and appealing electronic band structure. In this work, a porous hexagonal-prism g-C 3 N 4 (ACNH) photocatalyst was successfully synthesized via an acetic acid-assisted supramolecular assembly approach followed by calcination. The resulting ACNH materials have a corrugated and closely packed porous structure, which is composed of thin layers about 30 nm in thickness. The specific surface area of ACNH is as high as 67.7 m2 g−1, which is approximately 8-fold of bulk g-C 3 N 4. Moreover, the porous structure induces the red shift of the absorption edge and facilitates the photo-induced charge separation of g-C 3 N 4. Compared to bulk g-C 3 N 4 , the ACNH sample exhibits almost 13-fold improvement for the RhB degradation with the rate constant of 0.053 min−1. This finding suggests that the acid-assisted supramolecular assembly may become a feasible method to synthesize g-C 3 N 4 -based photocatalysts with higher surface area and photocatalytic activity. Graphical abstract Unlabelled Image Highlights • A facile way to synthesize g-C 3 N 4 from supermolecular precursors is proposed. • Porous g-C 3 N 4 hexagonal-prisms with high specific surface were obtained. • Acetic acid serves as pore-forming agent in the formation of porous g-C 3 N 4. • ACNH-3 exhibits almost 13-fold increase in RhB degradation than bulk g-C 3 N 4. [ABSTRACT FROM AUTHOR]