Towards AquaSun practical utilization: strong adhesion and lack of ecotoxicity of solar-driven antifouling sol-gel coating

The outcomes of adhesion and ecotoxicity tests carried out on metal specimens faithfully representing the surface of real ships, including the primer and tie coat layers typically applied on ship hull prior to deposition of the antifouling paint, show the practical applicability of "AquaSun" antifouling sol-gel coatings. Newly developed AquaSun coatings share superhydrophicity (contact angle >115) and exceptionally high scratch resistance (ASTM 5B). Coupled to the ecofriendly antifouling mechanism based on continuous H2O2 formation upon exposure to solar light and foul release due to low surface energy, these results open the route to the practical utilization of these novel marine coatings.

Towards AquaSun practical utilization: strong adhesion and lack of ecotoxicity of solar-driven antifouling sol-gel coating

The outcomes of adhesion and ecotoxicity tests carried out on metal specimens faithfully representing the surface of real ships, including the primer and tie coat layers typically applied on ship hull prior to deposition of the antifouling paint, show the practical applicability of "AquaSun" antifouling sol-gel coatings. Newly developed AquaSun coatings share superhydrophicity (contact angle >115) and exceptionally high scratch resistance (ASTM 5B). Coupled to the ecofriendly antifouling mechanism based on continuous H2O2 formation upon exposure to solar light and foul release due to low surface energy, these results open the route to the practical utilization of these novel marine coatings.

Detecting reactive oxygen species in free-living symbiotic dinoflagellates exposed to nanoparticles v1

2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) is a popular fluorescent probe for the detection of oxidative stress in cells. Since the probe can be prone to auto-oxidation, carboxy-2',7'-dichlorodihydrofluorescein-diacetate (carboxy-H2DCF-DA) which is more stable and easily penetrates cell membranes is often reported in the literature instead. Upon crossing the cell membrane, esterases hydrolyse DCFH-DA to DCFH, which remains trapped within cells. The oxidation of DCFH yields DCF, a fluorescent compound which can be measured using excitation/emission wavelengths of 485-495/520-530 nm. Due to several cases of interference when used in cellular systems, DCFH-DA is a general marker of the cellular oxidative stress rather than a specific indicator H2O2 formation or other ROS.

Spherical Polydopamine-Modified Carbon-Felt Cathode with an Active Indole Structure for Efficient Hydrogen Peroxide Electroproduction

As one of the most promising methods for H2O2 production, H2O2 electroproduction has received increasingly more attention. In this study, a spherical particle polydopamine (pDA) modified carbon felt (noted as ht-pDA/ACF) for H2O2 production was fabricated. At a constant potential of 2.0 V and pH of 1.0, the H2O2 production of the ht-pDA/ACF cathode reached 220 mg/L after 6 h of electrolyzing, compared to the 30 mg/L H2O2 production of raw carbon felt. Firstly, the spherical pDA exposes more active sites that are favorable to the 2e− ORR compared to pDA film. Secondly, the ring cleavage and re-cyclization of indole structure in the pDA during electrolyzing could form the radicals that act as the intermediate to the H2O2 formation. This research exhibits a low-cost method to modify carbon materials for effective H2O2 electroproduction. The ht-pDA/ACF cathode is promising for green H2O2 production and wastewater treatment.

Lignin as a Multifunctional Photocatalyst for Solar-Powered Biocatalytic Oxyfunctionalization of C-H Bonds

Lignin is a key structural material in all terrestrial plants that is responsible for cell wall formation, water transportation, seed protection, and stress adaptation. Each year, pulp and paper industry produces approximately 50 million metric tons of lignin as waste, 95% of which is combusted or abandoned. Here, we report a new multifunctionality of lignin as a photocatalyst (e.g., synergistic formation of H2O2 formation through O2 reduction and H2O oxidation, use of H2O as an electron donor, and OH• -scavenging activity). Our spectroscopic and photoelectrochemical analyses reveal the photophysical characteristics (e.g., light absorption, charge separation/transfer) of lignin models [e.g., lignosulfonate (LS) and kraft lignin (KL)] and their electronic properties [HOMO-LUMO gap: 2.67 eV (LS), 2.95 eV (KL), LUMO: -0.VRHE (LS) and -0.26 VRHE (KL), HOMO: 2.44 VRHE (LS) and 2.69 VRHE (KL)]. We demonstrate lignin-sensitized redox chemistry, such as (i) H2O2 formation through O2 reduction using H2O as an electron donor and (ii) O2 evolution through H2O oxidation, under visible light. Furthermore, the integration of lignin and H2O2-dependent unspecific peroxygenases (UPOs) enables enantiospecific oxyfunctionalization reactions (e.g., benzylic hydroxylation, alkane hydroxylation, styrene epoxidation). Lignin photocatalysts solve existing issues (e.g., requirement of artificial electron donors, H2O2- or OH• -driven inactivation of UPO) related to the sustainable activation of UPO. The lignin/UPO hybrid achieves a total turnover number of enzyme of 81070, the highest value ever recorded for solar-powered biocatalytic oxyfunctionalization in photochemical platforms. This work demonstrates the propriety of lignin in robust photocatalyst/biocatalyst hybrids for artificial photosynthesis.

Lignin as a Multifunctional Photocatalyst for Solar-Powered Biocatalytic Oxyfunctionalization of C-H Bonds

Lignin is a key structural material in all terrestrial plants that is responsible for cell wall formation, water transportation, seed protection, and stress adaptation. Each year, pulp and paper industry produces approximately 50 million metric tons of lignin as waste, 95% of which is combusted or abandoned. Here, we report a new multifunctionality of lignin as a photocatalyst (e.g., synergistic formation of H2O2 formation through O2 reduction and H2O oxidation, use of H2O as an electron donor, and OH• -scavenging activity). Our spectroscopic and photoelectrochemical analyses reveal the photophysical characteristics (e.g., light absorption, charge separation/transfer) of lignin models [e.g., lignosulfonate (LS) and kraft lignin (KL)] and their electronic properties [HOMO-LUMO gap: 2.67 eV (LS), 2.95 eV (KL), LUMO: -0.VRHE (LS) and -0.26 VRHE (KL), HOMO: 2.44 VRHE (LS) and 2.69 VRHE (KL)]. We demonstrate lignin-sensitized redox chemistry, such as (i) H2O2 formation through O2 reduction using H2O as an electron donor and (ii) O2 evolution through H2O oxidation, under visible light. Furthermore, the integration of lignin and H2O2-dependent unspecific peroxygenases (UPOs) enables enantiospecific oxyfunctionalization reactions (e.g., benzylic hydroxylation, alkane hydroxylation, styrene epoxidation). Lignin photocatalysts solve existing issues (e.g., requirement of artificial electron donors, H2O2- or OH• -driven inactivation of UPO) related to the sustainable activation of UPO. The lignin/UPO hybrid achieves a total turnover number of enzyme of 81070, the highest value ever recorded for solar-powered biocatalytic oxyfunctionalization in photochemical platforms. This work demonstrates the propriety of lignin in robust photocatalyst/biocatalyst hybrids for artificial photosynthesis.

Multiple Selectivity-Determining Mechanisms of H2O2 Formation in Iron Porphyrin-Catalysed Oxygen Reduction

Multiple H2O2-forming mechanisms are accessible in Fe(porphyrin)-catalyzed oxygen reduction, a key reaction in both fuel cell technologies and oxygen-utilizing enzymes. Our kinetic analysis reveals that the porphyrin secondary structure dictates...