Nanofabrication of a Solid-State, Mesoporous Nanoparticle Composite for Efficient Photocatalytic Hydrogen Generation

Room-temperature self-assembly was used to fabricate a periodic array of uniformly sized Al³⁺ -doped SiO₂ nanoparticles (Al-SiO₂ NPs, 20-30 nm). The uniform mesoporous structure was suitable for uniformly incorporating and distributing Pt nanoparticles (PtNPs), which were used as hydrogen-evolution catalysts in artificial photosynthetic systems, without agglomeration during the catalytic reaction. When the surfaces of the Al-SiO₂ NPs were covered with an organic photocatalyst (2-phenyl-4-(1-naphthyl)quinolinium ion, QuPh⁺ -NA), each PtNP was surrounded by multiple QuPh⁺ -NA ions. The structure allowed the PtNP to receive multiple electrons from QuPh^. -NA molecules, which were generated by reduction of the photoexcited state of QuPh⁺ -NA ions (QuPh^. -NA^{. +} ) with β-dihydronicotinamide adenine dinucleotide (NADH), thereby resulting in efficient photocatalytic H₂ evolution.