Synthesis of Self-Assembled Porous Naphtalene Dianhydride-TiO2 Composites for Photocatalytic Hydrogen Production

Conversion of solar energy to clean energy via naphthalenetetracarboxylic dianhydride (ND)-based organic semiconductors represents a topic of research. Nonetheless, efforts in this area are challenging due to the rapid recombination of photogenerated electron-hole (e-h) pairs arising from over-accumulation. Herein, various n -type hybrid photocatalysts, ND-TiO 2 (x:y) (x and y represent the ratios of ND and TiO 2 , respectively), featuring excellent visible-light responsiveness, fast separation and migration ability of charge carriers, and permanent porosity, are constructed via a sol–gel self-assembly approach. The rational assembly of ND with TiO 2 not only effectively inhibits the problematic overgrowth of ND but also enables the composites with excellent visible-light responsiveness, and facilitates the separation and migration of charge carriers, thus resulting in greatly improved photocatalytic H 2 evolution performance. The optimized composite ND-TiO 2 (1:10) with 0.38 wt% Pt nanoparticle loading presents a maximum hydrogen-evolution rate of 3.23 mmol·g −1 ·h −1 , with extraordinary TON (2446) and TOF (163.1 h −1 ), which are much higher than ND (0.031 mmol·g −1 ·h −1 ) and TiO 2 -Colloid (0.027 mmol·g −1 ·h −1 ) counterparts. In addition, the underlying photocatalytic mechanism is well established through comprehensive experiments and computational studies.