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This study reports on the electrochemical characterisation of dioleoyl phospatidylcholine (DOPC) bilayer structures on a negatively polarised mercury (Hg) electrode. The bilayers are stable on the Hg surface between −1.0 and −1.3 V applied potential. The experimental approaches were:- (i) rapid cyclic voltammetry (RCV) to “fingerprint” the bilayers, (ii) potential step experiments to record Zn 2+ reduction and, (iii) electrochemical impedance. The results show the following. Both the specific capacitance (5 μF cm −2 ) and the specific resistance of the bilayer are higher and lower respectively than that of a defect-free free standing DOPC bilayer. This indicates the presence of water and ions in the bilayer within an applied negative field. The bilayer's resistance to electrolyte movement decreases with increase in negative potential to a minimum at −1.3 V. The DOPC bilayer is less permeable to Zn 2+ ions compared to the DOPC monolayer coated electrode at applied negative potentials and its permeability to Zn 2+ increases with an increase in negative applied potential. The specific capacitance of the bilayer increases to about 7.5 μF cm −2 with increase in applied negative potential showing the increasing significance of water in the bilayer commensurate with its increased permeability to ions. Adsorption of SiO 2 nanoparticles on the bilayer surface causes a step negative potential shift in the anodic capacitance current bilayer reformation peak indicating an acceleration of the bilayer reformation process. [ABSTRACT FROM AUTHOR]

The present study investigates the effect of electrolyte ions on the occurrence of potential induced phase transitions at ca. -0.93 V and -0.99 V vs Ag/AgCl respectively of dioleoyl phosphatidylcholine (DOPC) monolayers on the mercury (Hg) surface. The interaction of both inorganic and organic electrolytes with DOPC was studied and it was shown that the alterations in the nature of the capacitance peaks representing the successive phase transitions depend on the ionic strength and the interfacial properties of the electrolyte ions. Higher ionic strength and cations with stronger binding affinity to DOPC give rise to steeper electric fields across the phospholipid layer shifting the apparent potential characterising capacitance peak-1 to more positive values. Conversely the anion, I − , which binds to DOPC, lessens the field gradient across the lipid and shifts the potential characterising capacitance peak-1 to more negative potentials. At more negative potentials to those characterising capacitance peak-1, electrolyte penetrates the DOPC. As a consequence a higher ionic strength and smaller hydrated cations with higher charge density enhance the screening of Hg, leading to stronger electric fields at the Hg surface. This effect shortens the onset and increases the rate dependence on the potential of the adsorption of bilayer patches to Hg by a nucleation and growth (N & G) process. [ABSTRACT FROM AUTHOR]

Summary: The rapid rise in the production of hazardous waste in the environment, particularly single-use plastics, has prompted the development of sustainable yet cost-effective alternatives. This research aims to create bioplastic films using renewable energy sour ces. To prevent toxic side products, the composite bioplastics synthesized from sweet potato starch are incorporated with biogenically synthesized ZnO NPs. Biocomposite films were characterized by their morphology, water vapor permeability (WVP), biodegradability, thermal and mechanical properties. It was noted that the ZnO NPs had substantial effects on the tensile properties of the nanocomposite films. The addition of ZnO NPs to the starch bioplastic films considerably enhanced tensile strength from 1.41 to 2.26 MPa, elongation from 78.20 to 114.91%, and Young's modulus from 1.62 to 2.40 MPa. The incorporation of ZnO NPs lowered the degree of WVP and film solubility value compared to those of the starch films. The bioplastic film incorporated with ZnO NPs had effective UV absorption and transparency. The shift in the peaks in the FT-IR spectra confirmed the relationship between the polymer matrix and the ZnO NPs. Thermal degradation of bio nanocomposite at 339.60 oc is shown by a consistent reduction in TGA between 240 oc and 410 oc. The high melting temperature (Tm) of 144 oc for starch film and 201.86 oc for bio nanocomposite was found using DSC analysis. SEM analysis revealed that biocomposite films had better compatible morphologies with small cracks and the roughness of films increased with the addition of ZnO NPs content. The biodegradability of the biocomposite films was analyzed through the soil burial method. The bioplastic produced in this study has the potential to be a viable alternative to existing conventional plastics in the packaging industry. [ABSTRACT FROM AUTHOR]

Photoreforming biomass-derived waste such as glycerol into hydrogen fuel is a renewable hydrogen generation technology that has the potential to become important due to unavoidable CO2 production during methane steam reforming. Despite tremendous efforts, the challenge of developing highly active photocatalysts at a low cost still remains elusive. Here, we developed a novel photocatalyst with a hybrid support comprising reduced graphene oxide (rGO) and TiO2 nanorods (TNR). rGO in the hybrid support not only performed as an excellent scavenger of electrons from the semiconductor conduction band due to its suitable electrochemical potential, but also acted as an electron transport highway to the metal co-catalyst, which otherwise is not possible by simply increasing metal loading due to the shadowing effect. A series of hybrid supports with different TNR and rGO ratios were prepared by the deposition method. Pd nanoparticles were deposited over hybrid support through the chemical reduction method. Pd/rGO-TNRs photocatalyst containing 4 wt.% rGO contents in the support and 1 wt.% nominal Pd loading demonstrated hydrogen production activity ~41 mmols h−1g−1, which is 4 and 40 times greater than benchmark Au/TiO2 and pristine P25. The findings of this works provide a new strategy in optimizing charge extraction from TiO2, which otherwise has remained impossible due to a fixed tradeoff between metal loading and the detrimental shadowing effect. [ABSTRACT FROM AUTHOR]