RESUMO
Active colloidal catalysts inspired by glutathione peroxidase (GPx) were synthesized by integration of catalytically active selenium (Se) moieties into aqueous microgels. A diselenide crosslinker (Se X-linker) was successfully synthesized and incorporated into microgels through precipitation polymerization, along with the conventional crosslinker N,N'-methylenebis(acrylamide) (BIS). Diselenide bonds within the microgels were cleaved through oxidation by H2 O2 and converted to seleninic acid whilst maintaining the intact microgel microstructure. Through this approach catalytically active microgels with variable amounts of seleninic acid were synthesized. Remarkably, the microgels exhibited higher catalytic activity and selectivity at low reaction temperatures than the molecular Se catalyst in a model oxidation reaction of acrolein to acrylic acid and methyl acrylate.
Assuntos
Microgéis/química , Selênio/química , Catálise , OxirreduçãoRESUMO
Molybdenum disulphide (MoS2) is a layered material with interesting photocatalytic properties. In this study, a layered MoS2 was produced using a hydrothermal method. The obtained material was characterised by XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscopy), UV-Vis spectroscopy, DLS (dynamic light scattering), and zeta potential analysis. For the evaluation of the photocatalytic properties of layered MoS2, a solution of bromophenol blue (BPB) and the catalyst was illuminated for 120 minutes. According to the experimental results, MoS2 exhibited excellent catalytic activity in BPB degradation. The MoS2 preparation method enabled improved light harvesting, avoided fast charge recombination (related to bulk MoS2), and created a large number of suitable electron transfer sites for photocatalytic reactions. Simulation of BPB decay and bromide production was carried out for a further understanding of MoS2 photocatalytic action. The simulation results proved the reduction mechanism of BPB photodegradation.