Juglans Sporopollenin for High-Performance Supercapacitor Electrode Design

Abstract

Recently, plant pollen has been used as a source of activated carbon to produce carbon-containing supercapacitor electrodes. However, in this study, pollen was used as a biotemplate with a completely different approach. As a biotemplate, pollen offers a wide range of varieties in terms of exterior, porosity, shape, and size. An electrode formed by the use of metal oxide grown on the pollen exine layer (sporopollenin microcapsules) as the active substance will inevitably exhibit good electrochemical capacitive properties. Juglans male flowers have been distinguished by dissection from anthers. Isolation of pollen grains from anthers was carried out using sieving from suitable sieves (45–200 μm). Juglans sporopollenin exine microcapsules (SECs) were separated from the intine and protoplasm by acetolysis in combination with reflux. The solution containing SECs, metal ions, and Ni foam was put into a Teflon-lined hydrothermal container, and then, it was reacted at 120 °C for 15 h. The resulting precipitate, as well as the Ni foam, was heat-treated at 300 and 360 °C for 3 h in air. The raw pollen, chemically treated pollen, and cobalt-coated SEC (CoSEC) and CoSEC/Ni foam were characterized using scanning electron microscopy, Brunauer–Emmett–Teller surface area analysis, thermogravimetric analysis, and X-ray diffraction techniques. Two different types of supercapacitor electrode designs, with the use of exine microcapsules of Juglans sporopollenin, were performed for the first time. The maximum specific capacitance was up to 1691 F g –1 at 5 A g –1 .

Role of Sporopollenin Shell Interfacial Properties in Protein Adsorption

“…Black walnut sporopollenin shells had a significantly higher ( p < 0.001, one-way ANOVA) specific surface area than sporopollenin shells of other species. This result of the surface area of black walnut contradicts a recent report, where Atalay et al reported a much lower surface area (1.59 m 2 /g) and a different adsorption isotherm for black walnut sporopollenin shells. Specifically, the adsorption isotherm reported by Atalay et al showed a lack of a characteristic capillary condensation phenomenon associated with sporopollenin shells.…”

“…While a majority of the studies have reported a surface area of about 10 m 2 /g for sporopollenin shells isolated from pistachio pollen, 24 clubmoss spores, 25 and rape pollen, 26 others have reported a significantly higher (72 m 2 /g for date palm pollen) 27 or a significantly lower (1.59 m 2 /g for black walnut (BW) pollen) surface area. 28 This broad range of reported surface areas for sporopollenin shells prompted us to investigate the surface area of sporopollenin shells from a diverse pollen species to reach a conclusive agreement.…”

Different Plant Sporopollenin Exine Capsules and Their Multifunctional Usage

“…Among these, phosphoric acid provides clean and less damaged SECs. 8 , 14 , 34 , 37 − 39 Therefore, phosphoric acid usage was preferred for its advantages in this study. For the acidolysis process, the precipitate was suspended in 200 mL of orthophosphoric acid in a 500 mL round-bottom flask.…”

“…Several acids such as hydrochloric acid, phosphoric acid, and sulfuric acid are used for the acidolysis step of SEC extraction. Among these, phosphoric acid provides clean and less damaged SECs. ,,,− Therefore, phosphoric acid usage was preferred for its advantages in this study. For the acidolysis process, the precipitate was suspended in 200 mL of orthophosphoric acid in a 500 mL round-bottom flask.…”

Nanomaterials Derived from a Template Method for Supercapacitor Applications

“…Recently, plant pollen has been used as a source of activated carbon to produce carbon-containing supercapacitor electrodes. But, Atalay et al [28] has used pollen as a biotemplate through a completely different approach, which is differ from traditional process (Figure 4A). As a kind of biotemplate, pollen has a wide diversity in terms of appearance, porosity, shape and size.…”