Plant Photocatalysts: Photoinduced Oxidation and Reduction Abilities of Plant Leaf Ashes under Solar Light

Abstract

Plant leaf ashes were obtained via the high temperature calcination of the leaves of various plants, such as sugarcane, couchgrass, bracteata, garlic sprout, and the yellowish leek. Although the photosynthesis systems in plant leaves cannot exist after calcination, minerals in these ashes were found to exhibit photochemical activities. The samples showed solar light photocatalytic oxidation activities sufficient to degrade methylene blue dye. They were also shown to possess intrinsic dehydrogenase-like activities in reducing the colorless electron acceptor 2,3,5-triphenyltetrazolium chloride to a red formazan precipitate under solar light irradiation. The possible reasons behind these two unreported phenomena were also investigated. These ashes were characterized using a combination of physicochemical techniques. Moreover, our findings exemplify how the soluble and insoluble minerals in plant leaf ashes can be synergistically designed to yield next-generation photocatalysts. It may also lead to advances in artificial photosynthesis and photocatalytic dehydrogenase.

Catalytic Ozonation of Reactive Black 5 in Aqueous Solution Using Iron-Loaded Dead Leaf Ash for Wastewater Remediation

“…The Fe 2+ peak is traced at 2 theta of 41.03, which indicates the presence of iron, whose valency did not change after its addition to wastewater containing the RB-5 treatment. The peaks obtained at 31.03 and 27.22 degrees correspond to other major constituents in ash, such as Ca and P, respectively [ 48 , 49 ].…”

Biotemplated heterostructure materials: opportunities for the elaboration of new photocatalysts and selective-oxidation catalysts

“…We report for the first time that minerals in plant leaf ashes after the removal of three key aspects (antenna, reaction center, and quinine pool) of a primary process in natural photosynthesis have abilities to carry out two important photocatalytic reactions in vitro : photodegradation of organic dyes and photoreduction of 2,3,5-triphenyl tetrazolium chloride under solar light irradiation. 102 That is, the photocatalysts were obtained by planting instead of chemical synthesis. Moreover, our findings demonstrate the potential of utilizing both soluble and insoluble minerals present in plant leaf ashes to create advanced photocatalysts.…”