Photo- &amp; radio-chromic iron-doped tungstic acids fabricated via submerged photosynthesis

Murakami, Shuntaro; Zhang, Lihua; Jeem, Melbert; Okamoto, Kazumasa; Nakagawa, Yuki; Shibayama, Tamaki; Ohnuma, Masato; Watanabe, Seiichi

doi:10.1016/j.optmat.2021.111966

Cited by 6 publications

(10 citation statements)

References 40 publications

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“…Figure illustrates the growth mechanisms of Mo–W hydrated nano-oxides from previous studies and crystal and morphology analysis. , The process of metallic Mo and W conversion to ions can be expressed as normalW + 3 normalH 2 normalO 2 → normalW normalO 4 2 − + 2 normalH + + 2 normalH 2 normalO normalM normalo + 3 normalH 2 normalO 2 → normalM normalo normalO 4 2 − + 2 normalH + + 2 normalH 2 normalO …”

Section: Resultsmentioning

confidence: 99%

“…Typically, these studies synthesized doped TMOs via chemical solution synthesis, such as hydrothermal or sol–gel methods. − However, these methods either have stringent temperature and pressure requirements or use impure precursors, increasing production costs, incorporating impurities into TMOs, and altering their physical properties. Herein, we propose the submerged photosynthesis crystallite (SPSC) method to fabricate Mo–W nano-oxide composites. , Fabricating nano-oxides from metallic raw materials via photo-irradiation in an aqueous solvent so that processing can be conducted conveniently at room temperature and pressure is the basic concept of the SPSC method. Additionally, the SPSC method eliminates unnecessary impurities by substituting complex chemical solutions with an aqueous solvent.…”

Section: Introductionmentioning

confidence: 99%

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Submerged Photosynthesis of Molybdenum–Tungsten Nanostructures for Supercapacitor Application

Lin

Jeem

Zhang

et al. 2023

ACS Appl. Nano Mater.

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Research on electrochemical energy storage devices aims to produce supercapacitors via a facile and nonpolluting method. Because of unnecessary elemental doping and disordered morphologies of nano-oxides, impurities in raw materials during the conventional fabrication process would reduce the pseudocapacitance. Herein, we propose a submerged photosynthesis crystalline method for synthesizing oxygen vacancy (Vo)-enriched Mo–W oxide hydrates and Mo-doped tungsten oxide hydrate nanocomposites at 55 °C and normal pressure. In addition, this study describes the impact of Vos on pseudocapacitance using ab initio calculations based on density functional theory. Doping the WO3·0.33H2O lattice with Mo and Vos brings the conduction band closer to the Fermi energy level. The comparison of the ultraviolet–visible–near-infrared (UV–vis–NIR) irradiation spectrum and absorption coefficient calculation suggests that Mo and Vo doping is responsible for the NIR absorption. This study concludes that enriched Vos result in the highest specific capacitance and pseudocapacitive behavior of Mo x W1–x O3·0.33H2O.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Submerged Photosynthesis of Molybdenum–Tungsten Nanostructures for Supercapacitor Application

Lin

Jeem

Zhang

et al. 2023

ACS Appl. Nano Mater.

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“…The color change of the iron-doped tungstic acid chromic gel was observed for hydrogen detection via the following reaction: …”

Section: Methodsmentioning

confidence: 99%

“…Then, we attempted to quantitatively evaluate the diffusion of aqua ions of protons and hydroxide ions by observing the color change of the BTB-agar hydrogel due to the AiS phenomenon. In addition, hydrogen generation during the iron corrosion process was confirmed by a chromic gel of iron-doped tungstic acids . Then, applying the quantitative evaluation method of aqua ion diffusion, we evaluated the activation energy and predicted the pH distribution in the AiS phenomenon using computer simulation.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative Evaluation of the Diffusion Coefficients of Aqua Ions in Hydrogels via Iron Corrosion

Takai

Murakami

Zhang

et al. 2022

ACS Appl. Eng. Mater.

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A method to quantitatively evaluate the diffusion coefficient of aqua ions, viz. protons and hydroxide ions, in hydrogels using iron corrosion was developed. In this paper, the locations of the anode and cathode formation, which dominate iron corrosion, were experimentally controlled using pseudosacrificial corrosion protection with conductive anticorrosion ink. First, hydrogen (atomic) generation during the process was confirmed by a chromic gel with iron-doped tungstic acids. Then, the diffusion of aqua ions generated from them was visualized using a BTB-agar hydrogel with BTB (bromothymol blue), and the diffusion coefficient of aqua ions was evaluated using Fick's law by reading the time variation of luminance. The temperature dependence of the diffusion coefficient was also examined, and the activation energies were evaluated as 19.0 ± 5.9 and 25.9 ± 3.3 kJ/mol for hydroxide ions and proton, respectively. Furthermore, the experimentally evaluated diffusion coefficients of aqua ions were used in a computer simulation to solve the diffusion equation to predict the pH distribution. The diffusion behaviors of aqua ions by the experiment are almost consistent with the simulation results and demonstrate the feasibility of the present method.

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Defect Driven Opto‐Critical Phases Tuned for All‐Solar Utilization

Jeem,

Hayano,

Miyashita

et al. 2023

Advanced Materials

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Materials imbued with uniformly dispersed, photo‐responsive nanoparticles are instrumental in sustainable energy and photonic applications. Conventional methods, however, constrain their all‐solar response. An innovative alternative is proposed: submerged photo‐synthesis of crystallites (SPsC). It is shown that strategic doping with copper and oxygen vacancies can induce opto‐critical phases from the non‐stoichiometric tungstic acids (WO3·H2O). These opto‐critical phases enable a dynamic equilibrium shift in lattice defect stabilization, facilitating an unprecedented a whole solar wavelength response. This response manifests as photothermal, photo‐assisted water evaporation, and photo‐electrochemical characteristics. Harnessing all‐solar energy, this one‐pot SPsC strategy may steer the design and development of advanced oxide materials, enhancing functionality across diverse application domains.This article is protected by copyright. All rights reserved

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Photo- & radio-chromic iron-doped tungstic acids fabricated via submerged photosynthesis

Cited by 6 publications

References 40 publications

Submerged Photosynthesis of Molybdenum–Tungsten Nanostructures for Supercapacitor Application

Submerged Photosynthesis of Molybdenum–Tungsten Nanostructures for Supercapacitor Application

Quantitative Evaluation of the Diffusion Coefficients of Aqua Ions in Hydrogels via Iron Corrosion

Defect Driven Opto‐Critical Phases Tuned for All‐Solar Utilization

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