Botanically Templated Monolithic Macrostructured Zinc Oxide Materials for Photocatalysis

Abstract

With an increased focus on light energy to facilitate catalytic processes, photocatalysts have been intensively studied for a wide range of energy and environmental applications. In this report, we describe the use of chemically dehydrated leaves as sacrificial foam-like templates for the growth of monolithic macrostructured semiconducting zinc oxide and nickel or cobalt doped zinc oxide materials. The composition and structure of these templated zinc oxides were characterized using X-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. Optical properties were examined using solid-state UV–vis diffuse reflectance spectroscopy. The metal-doped ZnO materials have enhanced visible absorption and lower band gaps as compared to ZnO. The botanically templated ZnO materials retain the macroscopic cellular form of the leaf template with fused nanoparticle walls. Their UV photocatalytic oxidative abilities were investigated using methylene blue dye degradation in air. The leaf templated zinc oxides degrade ~85% of methylene blue dye with 30 min of UV illumination. Nickel and cobalt doped zinc oxides showed varying degrees of decreased UV and visible light photocatalytic activity, possibly due to metal-mediated charge recombination. The mild chemical dehydration process here allows complex soft botanical structures to be easily utilized for templating materials.

Hydrothermal fabrication, characterization and RSM optimization of cobalt-doped zinc oxide nanoparticles for antibiotic photodegradation under visible light

“…Hy-ZnO NPs have a wavelength of 376 nm (3.29eV), whereas Co–ZnO exhibits Three absorption visible bands shown in the transmission spectra 565 nm (2.194eV), 615 nm (2.016 eV), and 663 nm (1.87 eV), which corresponds to the primary absorption peaks of the Co 2+ tetrahedral molecular ions 49 .…”

Gifts from Nature: Bio‐Inspired Materials for Rechargeable Secondary Batteries

“…[109][110][111][112] An advantage of this method is that it is easy to control the size of the final product by selecting the appropriate bioinspired material, ranging from 10 nm deoxyribonucleic acid (DNA) to wood that is a few millimeters (Table 2). [113][114][115][116][117][118] Additionally, with the biotemplating method, the biogenic elements can be applied to the final product. For example, carbon contained in bio-inspired material remains in final product and is used as electrode material.…”

“…[116] ref. [117] ref. [118] material provides a continuous conductive pathway, allowing the electrodes to be constructed without a conductive agent.…”