Designing of N-Doped Graphene Quantum Dot/NiAl Layered Double Hydroxide/TiO₂ Heterostructure for Enhanced Photocatalytic Hydrogen Production

Hydrogen energy across the world is acknowledged as a clean and sustainable chemical energy source. Nowadays, it is crucial to develop photocatalysts that can effectively use sunlight to produce hydrogen through photocatalysis. The current study synthesizes N-doped graphene quantum dot/NiAl layered double hydroxide/TiO2 (N-GQDs LDH/TiO2) to enhance their photocatalytic activity by achieving excellent charge separation and transfer efficiency. To verify the structural, morphological, and crystalline phase characteristics, FE-SEM, HR-TEM, XRD, and XPS analyses were performed. The 10 wt % N-GQDs LDH/TiO2 (10% NG LDH) demonstrated outstanding photocatalytic efficiency for the evolution of H2 when subjected to simulated solar light. The photocatalyst uses ethylene glycol as a hole scavenger to produce an extraordinary rate of hydrogen 1332.11 μmol g–1 h–1 in under 5 h of irradiation. Furthermore, four consecutive cycles of photocatalysis with 10% NG LDH demonstrated that the synthesized material has excellent stability without altering its morphological framework, with the fourth cycle showing a little 7.07% decline in photocatalytic activity. The chemical pathways for H2 evolution across the most active 10% NG LDH were also thoroughly examined, and it was found that the heterojunction is crucial for improving electron–hole pair separation.