Visible-light photocatalytic regeneration of NADH using P-doped TiO2 nanoparticles

Silicon nanowires as a rechargeable template for hydride transfer in redox biocatalysis

We report a new possible application of hydrogen-terminated silicon nanowires (H-SiNWs) as a rechargeable template for hydride transfer in redox biocatalysis. H-SiNWs transfer hydride efficiently to regenerate NADH by oxidizing Si-H(x) bonds. The oxidized H-SiNWs were readily recharged for the continuous regeneration of NADH and enzymatic reactions.

Zn-containing porphyrin as a biomimetic light-harvesting molecule for biocatalyzed artificial photosynthesis

Among the porphyrin molecules with different metal insertion sites and functional ligands, Zn-porphyrin most efficiently regenerates NADH through photo-induced electron transfer in the presence of [Cp*Rh(bpy)H(2)O](2+), a rhodium-based electron mediator. Photochemical regeneration of NADH by Zn-porphyrin is successfully coupled with redox enzymatic synthesis under dark state conditions.

Photoenzymatic synthesis through sustainable NADH regeneration by SiO2-supported quantum dots

Sustainable photochemical NADH regeneration and redox-enzymatic synthesis are accomplished by using CdS nanocrystals grown on the surface of SiO(2) beads. CdS nanocrystals grown on SiO(2) beads worked efficiently as a visible-light absorbing photocatalyst for in situ NADH regeneration with high catalytic activity and minimal loss of activity despite repeated uses.

Photodegradation of methyl orange by photocatalyst of CNTs/P-TiO(2) under UV and visible-light irradiation

A novel nanoscale photocatalyst CNTs/P-TiO(2) was successfully prepared by hydrothermal method. The morphology and the physicochemical properties of the prepared samples were investigated using TEM, XPS, XRD, BET, FTIR, TG-DSC and UV-vis DRS spectroscopy. The photocatalytic activity was evaluated by degradation of methyl orange (MO) dye. The results demonstrated that CNTs/P-TiO(2) nanoparticles could effectively photodegrade MO not only under UV irradiation but also under visible-light (VL) irradiation. The MO degradation performance on CNTs/P-TiO(2) was superior to that of the commercial P25. The optimal mass ratio of CNTs to P-TiO(2) in the nanocomposite catalyst was 5:100. The synergetic effect was discussed in terms of different roles played by phosphorus doping and introducing CNTs into the composite catalysts.

Biogenic N-P-codoped TiO2: synthesis, characterization and photocatalytic properties

Four typical kinds of crop seeds are studied as non-metallic bio-precursors to synthesize biogenic N-P-codoped TiO(2) (BNP-TiO(2)). The as-prepared BNP-TiO(2) samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen-adsorption measurement and UV-Vis spectroscopy. The results show that BNP-TiO(2) possesses single anatase phase with mesopore structures, and nitrogen and phosphorus contained in original crop seeds are self-doped into the lattice as anions and cations, respectively. Besides, BNP-TiO(2) exhibits a strongly enhanced absorption in the UV-Vis light range and red shift of the absorption edge, implicating the highly efficient light-harvesting capacity and sensitization towards visible light. Furthermore, experiments of crystal violet degradation under Xe lamp irradiation indicate superior photocatalytic activity of BNP-TiO(2), of which the degradation rate is almost three times that of common TiO(2). Circled photocatalytic degradation also shows good photocatalytic stability of BNP-TiO(2). This work may pave a new and facile pathway of utilizing discarded biomass to synthesize desirable element-doped metal oxides based on biomass precursors.

Hydrothermal synthesis of ionic liquid [Bmim]OH-modified TiO2 nanoparticles with enhanced photocatalytic activity under visible light

TiO(2) nanocomposites modified with the ionic liquid [Bmim]OH are synthesized by a hydrothermal procedure. X-ray diffraction, Zeta-potential measurement, TEM, thermogravimetric analysis, photoluminescence, UV/Vis, FTIR, and X-ray photoelectron spectroscopy are used to characterize the TiO(2) nanocomposites. The TiO(2) nanocomposites consist of pure anatase particles of about 10 nm. The modification of [Bmim]OH on the surface of the TiO(2) particles extends the TiO(2) absorption edge to the visible-light region. The electrochemical redox potentials indicated that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of [Bmim]OH match well with the valence band (VB) and conduction band (CB) of the TiO(2) semiconductor. [Bmim]OH-modified TiO(2) is much more active than pristine TiO(2) under visible-light irradiation in the photocatalytic degradation of methylene blue in aqueous solution. [Bmim]OH is chemically bonded to the surface Ti-OH of TiO(2) particles rather than adsorbed on the surface. A possible mechanism for the photocatalysis is proposed.