Cr3+-ZnGa2O4@Pt for Light-Triggered Dark Catalytic Regeneration of Nicotinamide Coenzymes without Other Electron Mediators.

Photocatalysts for regeneration of reduced nicotinamide adenine dinucleotide (NADH) usually work with continuous lighting and electron mediators, which causes impracticability under dark conditions, risk of NADH reoxidation, and complex separation. To solve these problems, we present a new catalyst of tiny Pt nanoparticles photodeposited on chromium-doped zinc gallate (CZGO@Pt). Upon being light-triggered, the photogenerated electrons are stored in the traps of CZGO and then gradually released and transferred by Pt to directly reduce NAD+ after stoppage of illumination. Three lighting modes are compared to demonstrate the feasibility and advantage of this light-triggered dark catalysis. Within 4 h of reaction, the in-the-dark NADH yield reaches 75.0% under prelighting CZGO@5%Pt and it reaches 80.0% under prelighting CZGO@5%Pt and triethanolamine (TEOA). However, the NADH yield is only 53.5% under continuous lighting of CZGO@5%Pt, TEOA, and NAD+. Consequently, the light-triggered dark catalytic regeneration of NADH not only saves energy and operates easily but also significantly elevates the NADH yield. It thus would secure wide interests and applications in places where no light or only intermittent light is available.

Surface engineering of Al2O3 nanotubes by ureasolysis method for activating persulfate degradation of antibiotics.

Though ecofriendly, pure Al2O3 has never been used for activation of peroxodisulfate (PDS) to degrade pollutants. We report the fabrication of Al2O3 nanotubes by ureasolysis method for efficient activating PDS degradation of antibiotics. The fast ureasolysis in aqueous AlCl3 solution produces NH4Al(OH)2CO3 nanotubes, which are calcined to porous Al2O3 nanotubes, and the release of ammonia and carbon dioxide engineers the surface features of large surface area, numerous acidic-basic sites and suitable Zeta potentials. The synergy of these features facilitates the adsorption of the typical antibiotics ciprofloxacin and PDS activation, which is proved by experiment results and density functional theory simulation. The proposed Al2O3 nanotubes can catalyze 92-96% degradation of 10 ppm ciprofloxacin within 40 min, with chemical oxygen demand removal of 65-66% in aqueous, and 40-47% in whole including aqueous and catalysts. Ciprofloxacin at high concentration, other fluoroquinolones and tetracycline can also be effectively degraded. These data demonstrate the Al2O3 nanotubes prepared by the nature-inspired ureasolysis method has unique features and great potentials for antibiotics degradation.