Influencing factors for the migration of zinc ions in metal oxide powders

Lu, Dongzhu; Yishan, Jiang; Li, Jiawei; Qichao, Zhang; Huang, Yingjie; Hou, Baorong

doi:10.1016/j.jmrt.2023.03.106

Cited by 4 publications

(2 citation statements)

References 33 publications

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“…Under reductive conditions similar to our work, Xie et al have suggested that reducible metal oxides can migrate from zeolite surfaces to micropore channels . Furthermore, under the harsh reaction conditions used in our study, metal cations formed from metal oxides could have higher thermal mobility, accelerating ion exchange under reductive conditions. − It has been further suggested that under a reductive environment, InO + could convert to In + . , From our data, we conclude that these ion-exchanged species inhibit C–C coupling by reducing HZSM-5 acidity and promoting CH 4 formation via CH 3 OH hydrodeoxygenation (HDO).…”

Section: Resultssupporting

confidence: 82%

Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In₂O₃/HZSM-5 Tandem CO₂ Hydrogenation Catalyst

Mahnaz,

Mangalindan,

Dharmalingam

et al. 2024

ACS Sustainable Chem. Eng.

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Identifying the descriptors for the synergistic catalytic activity of bifunctional oxide-zeolite catalysts constitutes a formidable challenge in realizing the potential of tandem hydrogenation of CO 2 to hydrocarbons (HC) for sustainable fuel production. Herein, we combined CH 3 OH synthesis from CO 2 and H 2 on In 2 O 3 and methanol-to-hydrocarbons (MTH) conversion on HZSM-5 and discerned the descriptors by leveraging the distance-dependent reactivity of bifunctional In 2 O 3 and HZSM-5 admixtures. We modulated the distance between redox sites of In 2 O 3 and acid sites of HZSM-5 from milliscale (∼10 mm) to microscale (∼300 μm) and observed a 3-fold increase in space-time yield of HC and CH 3 OH (7.5 × 10 −5 mol C g cat −1 min −1 and 2.5 × 10 −5 mol C g cat −1 min −1 , respectively), due to a 10-fold increased rate of CH 3 OH advection (1.43 and 0.143 s −1 at microscale and milliscale, respectively) from redox to acid sites. Intriguingly, despite the potential of a three-order-of-magnitude enhanced CH 3 OH transfer at a nanoscale distance (∼300 nm), the sole product formed was CH 4 . Our reactivity data combined with Raman, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) revealed the occurrence of solid-state-ion-exchange (SSIE) between acid sites and In δ+ ions, likely forming In 2 O moieties, inhibiting C−C coupling and promoting CH 4 formation through CH 3 OH hydrodeoxygenation (HDO). Density functional theory (DFT) calculations further revealed that CH 3 OH adsorption on the In 2 O moiety with preadsorbed and dissociated H 2 forming an H−In−OH−In moiety is the likely reaction mechanism, with the kinetically relevant step appearing to be the hydrogenation of the methyl species. Overall, our study revealed that efficient CH 3 OH transfer and prevention of ion exchange are the key descriptors in achieving catalytic synergy in bifunctional In 2 O 3 /HZSM-5 systems.

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Section: Resultssupporting

confidence: 82%

Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In₂O₃/HZSM-5 Tandem CO₂ Hydrogenation Catalyst

Mahnaz,

Mangalindan,

Dharmalingam

et al. 2024

ACS Sustainable Chem. Eng.

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“…In particular, an increase in temperature led to a noticeable increase in the intensity of the ionic memristive effects in both films. This can be explained by the fact that a higher temperature promotes more active ion movement processes in the material, which facilitates ionic migration and leads to more pronounced effects of metal cation valence changes [9]. It is worth noting that high temperatures promote greater migration of defects in the crystal structure of the material, which can affect the efficiency of membrane switching.…”

Section: Source: Compiled By the Authormentioning

confidence: 99%

Ionic memristive effects on the nanometre scale in metal oxides: Understanding the process of valence change

Zavodyannyi

2023

Scientific Herald of Uzhhorod University Series Physics

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Relevance. The relevance of the study is due to the great potential of memristive effects, which are manifested in the change of material resistance under the influence of an external electric field and ionic fluxes. Aim. The aim is to analyse and study the mechanisms of ionic memristive effects, with a detailed consideration of the process of changing the valence of metal cations. Methodology. The work was based on the study of nanometre-sized metal oxides TiO2 and ZrO2. The materials were obtained by synthesis by chemical deposition using high-purity precursors. Results. The obtained results open up wide opportunities for the practical use of ionic membrane effects. The study of ionic memristive effects in TiO2 and ZrO2-based films has shown that the change in resistance occurs due to various mechanisms, including ionic migration, electrochemical reactions, and defect reorganization. Under the influence of an external electric field, a change in the resistance of both materials is observed. In TiO2, the resistance decreases with increasing voltage, while in ZrO2, an increase in resistance is observed. During additional experiments in the temperature range of 25-200 ℃, it was found that temperature significantly affects the ionic membrane effects. With its increase, a noticeable increase in the intensity of these effects in both materials is observed. Conclusions. The use of X-ray diffractometry and infrared spectroscopy revealed that changes in the valence of metal cations in both films occur under the influence of an electric field. The analysis of changes in the X-ray and infrared spectra showed the presence of modifications in the crystal and molecular structure in response to the electric field. In particular, the change in the positions and intensity of the peaks indicates a restructuring of the bonds in the crystal lattice. The paper proposes new studies to expand the understanding of these effects and to consider possible ways to improve membrane devices. The study of ionic memristive effects in TiO2 and ZrO2 is of great practical importance for the development of electronics and the creation of new generations of memristors and neuromorphic systems.

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Effective time of a diffusion source in a pack cementation process on the AZ91D magnesium alloy

Lu¹,

Ma²,

Fan³

et al. 2023

Journal of Materials Research and Technology

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Influencing factors for the migration of zinc ions in metal oxide powders

Cited by 4 publications

References 33 publications

Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In₂O₃/HZSM-5 Tandem CO₂ Hydrogenation Catalyst

Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In₂O₃/HZSM-5 Tandem CO₂ Hydrogenation Catalyst

Ionic memristive effects on the nanometre scale in metal oxides: Understanding the process of valence change

Effective time of a diffusion source in a pack cementation process on the AZ91D magnesium alloy

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Influencing factors for the migration of zinc ions in metal oxide powders

Cited by 4 publications

References 33 publications

Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In2O3/HZSM-5 Tandem CO2 Hydrogenation Catalyst

Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In2O3/HZSM-5 Tandem CO2 Hydrogenation Catalyst

Ionic memristive effects on the nanometre scale in metal oxides: Understanding the process of valence change

Effective time of a diffusion source in a pack cementation process on the AZ91D magnesium alloy

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Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In₂O₃/HZSM-5 Tandem CO₂ Hydrogenation Catalyst

Intermediate Transfer Rates and Solid-State Ion Exchange are Key Factors Determining the Bifunctionality of In₂O₃/HZSM-5 Tandem CO₂ Hydrogenation Catalyst