Dinitrogen
(N2) is earth’s most abundant form
of gas, and its photofixation into ammonia (NH3) is a sustainable
solution. Solar-driven photoreduction of N2 to NH3 at ambient temperature and pressure is a benign technique to generate
renewable fuels; however, the NH3 production is currently
limited to noble-metal-containing systems that operate at high pressure
and temperature. Herein, we assess the light-driven photoreduction
of N2 to NH3 and dye degradation activity of
γ-gallium oxide (γ-Ga2O3) hierarchical
nanostructures deposited on two-dimensional graphitic carbon nitride
(GCN). Using the advantage of surface nitrogen vacancies of GCN and
interfacial coupling of GCN-γ-Ga2O3 nanohybrid
catalysts, we were able to photoreduce N2 to NH3 under light irradiation at ambient conditions and effectively degrade
various organic dyes. The N2 photoreduction using GCN-γ-Ga2O3(10) nanohybrid yielded NH4
+ production rate of 355.5 μmol L–1 h–1, which is 1.6-fold and 16-fold higher than GCN and
γ-Ga2O3, respectively. The underlying
highlights of the hybrid catalyst presents economical route to aqueous-phase
N2 reduction into NH3 via heterogeneous photocatalysis
under solar light.
Conducting polymers, mainly polyaniline (PANI) and polypyrrole (PPY) with positive charges bind to the negatively charged bacterial membrane to interfere with bacterial activities. After this initial electrostatic adherence, the conducting polymers might partially penetrate the bacterial membrane and interact with other intracellular biomolecules. Conducting polymers can form polymer composites with metal, metal oxides, and nanoscale carbon materials as a new class of antimicrobial agents with enhanced antimicrobial properties. The accumulation of elevated oxygen reactive species (ROS) from composites of polymers-metal nanoparticles has harmful effects and induces cell death. Among such ROS, the hydroxyl radical with one unpaired electron in the structure is most effective as it can oxidize any bacterial biomolecules, leading to cell death. Future endeavors should focus on the combination of conducting polymers and their composites with antibiotics, small peptides, and natural molecules with antimicrobial properties. Such arsenals with low cytotoxicity are expected to eradicate the ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.
Considering the global spread of bacterial infections,
the development
of anti-biofilm surfaces with high antimicrobial activities is highly
desired. This work unraveled a simple, sonochemical method for coating
Cu2O nanoparticles (NPs) on three different flexible substrates:
polyester (PE), nylon 2 (N2), and polyethylene (PEL). The introduction
of Cu2O NPs on these substrates enhanced their surface
hydrophobicity, induced ROS generation, and completely inhibited the
growth of sensitive (Escherichia coli and Staphyloccocus aureus) and drug-resistant
(MDR E. coli and MRSA) planktonic and
biofilm. The experimental results confirmed that Cu2O-PE
exhibited complete biofilm mass reduction ability for all four strains,
whereas Cu2O-N2 showed more than 99% biomass inhibition
against both drug-resistant and sensitive pathogens in 6 h. Moreover,
Cu2O-PEL also indicated a 99.95, 97.73, 98.00, and 99.20%
biomass reduction of MRSA, MDR E. coli, E. coli, and S. aureus, respectively. All substrates were investigated for time-dependent
inhibitions, and the associated biofilm mass and log reduction were
evaluated. The mechanisms of Cu2O NP action against the
mature biofilms include the generation of reactive oxygen species
(ROS) as well as electrostatic interaction between Cu2O
NPs and bacterial membranes. The current study could pave the way
for the commercialization of sonochemically coated Cu2O
NP flexible substrates for the prevention of microbial contamination
in hospitals and industrial environments.
Functionalized carbon dots (CDs) exhibit intriguing photo-exciton dynamics. CDs can donate or accept electrons depending on their functional groups and electrostatic characteristics. We exploited the electron-accepting capability of nitrogendoped graphitic carbon dots (N-g-CDs) to improve the chargecarrier separation of the polymeric carbon nitride (PCN) photocatalyst. L-Aspartic acid pyrolyzed at 320 °C yielded ∼25 nm size N-g-CDs that were embedded with PCN. The in-plane infiltration of nanosized N-g-CDs increased the surface area of PCN from 11.5 to 104.9 m 2 g −1 . The N-g-CDs/PCN hybrid catalyst tested for photocatalytic chromium reduction evidenced about a 3-fold higher rate than PCN. Also, the antibiotic tetracycline and rhodamine B dye rapidly degraded with faster degradation kinetics. The carrier dynamic analysis and computational investigations suggest that the electron acceptor feature of N-g-CDs governs the effective separation of photo-excitons and the high surface area of N-g-CDs/PCN contributes to photoactivity enhancement. This study offers insights into designing high-performance metal-free photocatalysts for water treatment applications.
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