Structure/Properties Relationship of Anionically Synthesized Diblock Copolymers "Grafted to" Chemically Modified Graphene

Graphene Oxide-Cytochrome c Multilayered Structures for Biocatalytic Applications: Decrypting the Role of Surfactant in Langmuir-Schaefer Layer Deposition

Graphene, a two-dimensional single-layer carbon allotrope, has attracted tremendous scientific interest due to its outstanding physicochemical properties. Its monatomic thickness, high specific surface area, and chemical stability render it an ideal building block for the development of well-ordered layered nanostructures with tailored properties. Herein, biohybrid graphene-based layer-by-layer structures are prepared by means of conventional and surfactant-assisted Langmuir-Schaefer layer deposition techniques, whereby cytochrome c molecules are accommodated within ordered layers of graphene oxide. The biocatalytic activity of the as-developed nanobio-architectures toward the enzymatic oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and decolorization of pinacyanol chloride is tested. The results show that the multilayer structures exhibit high biocatalytic activity and stability in the absence of surfactant molecules during the deposition of the monolayers.

Catalytic Decomposition of Residual Ozone over Cactus-like MnO2 Nanosphere: Synergistic Mechanism and SO2/H2O Interference

Ground-level ozone is an irritant and is harmful to human respiratory and nervous systems. Thus, four manganese oxides with different crystals were hydrothermally synthesized to decompose residual ozone (deO₃) in an ozone synergistic-oxidation system. Among them, a cactus-like MnO₂-IV nanosphere exhibited the highest deO₃ activity, with excellent tolerance to water vapor and SO₂/H₂O, which could maintain >88% deO₃ efficiency in the high-humidity and sulfur-containing conditions. It benefits from the unique morphology, high specific surface area, superior redox properties, oxygen chemisorption capabilities, abundant surface-active hydroxyl species, and low valence Mn species. More importantly, the detailed interference mechanism of O₂/O₃/H₂O/SO₂ molecules on MnO₂-IV was revealed utilizing in situ diffused reflectance infrared Fourier transform spectroscopy and X-ray photoelectron spectroscopy. H₂O generally caused recoverable deactivation, but that caused by SO₂ was irreversible. The synergistic effect of SO₂/H₂O promoted the formation of an unstable sulfate species, thereby deepening the deactivation but inhibiting the irreversible poisoning. Finally, nine specific steps to decompose ozone via surface-active hydroxyl/intermediates were established.