Comparative Study of Graphene-Based Structural Electrodes

Graphene based electrodes have gained significant attention in the field of high-performance energy devices. Among different types of graphene-electrode assemblies, our team chose to approach 3D gel morphology due to its high specific surface area, and high porosity. We prepared graphene hydrogels by controlled reduction-led self-assembly of graphene oxide nanosheets in presence of ammonia. Our recent approach considers aramid nanofibers as fillers for mechanical enhancement in 3D graphene oxide hydrogels based electrodes. Several characterization techniques are discussed to measure the mechanical and electrochemical properties of electrodes. These performance metrics can be used to compare the performance of gel based electrodes with other electrodes types. To get an in-depth understanding of how graphene architecture affects the electrode performance and to determine what factors give rise to better performing structural electrode, several literatures are reviewed as a comparative study

Comparative Study of Graphene-Based Structural Electrodes

Graphene based electrodes have gained significant attention in the field of high-performance energy devices. Among different types of graphene-electrode assemblies, our team chose to approach 3D gel morphology due to its high specific surface area, and high porosity. We prepared graphene hydrogels by controlled reduction-led self-assembly of graphene oxide nanosheets in presence of ammonia. Our recent approach considers aramid nanofibers as fillers for mechanical enhancement in 3D graphene oxide hydrogels based electrodes. Several characterization techniques are discussed to measure the mechanical and electrochemical properties of electrodes. These performance metrics can be used to compare the performance of gel based electrodes with other electrodes types. To get an in-depth understanding of how graphene architecture affects the electrode performance and to determine what factors give rise to better performing structural electrode, several literatures are reviewed as a comparative study

Application of cellulose/lignin hydrogel beads as novel supports for immobilizing lipase

Lignocellulose-based hydrogels may have many potential applications in biomedical and biotechnological fields owing to their attractive properties including low cost, biodegradability, and biocompatibility. In this study, cellulose/lignin composite hydrogel beads were prepared by co-dissolution of cellulose and lignin in 1-ethyl-3-methylimidazolium acetate and then reconstitution with distilled water. Lipase from Candida rugosa was immobilized on various cellulose/lignin hydrogel beads. The results showed that lipase immobilized on cellulose/lignin beads showed higher activity and stability than those of lipase immobilized on pure cellulose beads. The activity and stability of immobilized lipase increased with the increase in the lignin content in the cellulose/lignin beads. The activity, protein loading, and specific activity of lipase immobilized on the optimal cellulose/lignin beads were 2.6, 2.2, and 1.2 times higher than those of lipase immobilized on cellulose beads, respectively. The effect of lignin on the activity of lipase immobilized on cellulose/lignin beads was statistically well predicted. The residual activity of lipase immobilized on the optimal cellulose/lignin beads after incubation for 12 h at 40 degrees C was 3.2 and 1.9 times higher than that of free lipase and lipase immobilized on cellulose beads, respectively. Interestingly, the half-life time of lipase immobilized on cellulose/lignin beads at pH 3.0 was 24 and 3 times higher than that of free lipase and that of lipase immobilized on cellulose beads, respectively. These results show that cellulose/lignin hydrogels may offer many potential applications in the biocatalytic, biomedical, and bioelectronic fields owing to their high biocompatibility, biodegradability, and controllable properties.clos

Effect of deep eutectic solvent mixtures on lipase activity and stability

DESs (deep eutectic solvents) have many potential applications as cosolvents or anhydrous reaction media for biocatalytic reactions, owing to their non-volatility, non-flammability, non-toxicity, biocompatibility, biodegradability, and low cost. In this work, choline chloride ([Ch]Cl)-based DESs and DES mixtures containing two hydrogen bond donors were used as cosolvents to enhance the activity and stability of Candida rugosa lipase in aqueous reactions. The activity of lipase in an aqueous solution of [Ch]Cl:urea:glycerol was 155% higher than that in buffer. The half-life time of lipase at 40 degrees C in an aqueous solution of [Ch]Cl:glycerol was enhanced by 9.2 times. The lipase showed the highest acid stability and base stability in the aqueous solutions of [Ch]Cl:glycerol:thiourea and [Ch]Cl:ethylene glycol:formamide, respectively. In general, glycerol-containing DES mixtures were very useful in enhancing the activity and stability of lipase, while formamide-containing DES mixtures could not efficiently enhance the activity and stability of lipase. To understand the effect of DES mixtures on the activity and stability of lipase in aqueous solution, four solvatochromic parameters of DES mixtures were determined. When the solvatochromic parameters of DES mixtures were correlated with the stability of lipase in aqueous solutions of DES mixtures, it was found that thermal stability and storage stability of lipase were associated with the hydrogen bond acidity of DES mixtures. Acid stability and base stability of lipase were correlated with polarity based on Reichardt's dye and the dipolarity/polarizability of DES mixtures, respectively.clos

Coplanar semiconductor-metal circuitry defined of few-layer MoTe2 via polymorphic heteroepitaxy

Crystal polymorphism selectively stabilizes the electronic phase of atomically thin transition-metal dichalcogenides (TMDCs) as metallic or semiconducting, suggesting the potential to integrate these polymorphs as circuit components in two-dimensional electronic circuitry. Developing a selective and sequential growth strategy for such two-dimensional polymorphs in the vapour phase is a critical step in this endeavour. Here, we report on the polymorphic integration of distinct metallic (1T') and semiconducting (2H) MoTe2 crystals within the same atomic planes by heteroepitaxy. The realized polymorphic coplanar contact is atomically coherent, and its barrier potential is spatially tight-confined over a length of only a few nanometres, with a lowest contact barrier height of similar to 25 meV. We also demonstrate the generality of our synthetic integration approach for other TMDC polymorph films with large areas.12