Polyoxometalates as promising materials for electrochromic devices

Wang, Shi Ming; Hwang, Jongun; Kim, Eunkyoung

doi:10.1039/c9tc01722d

Cited by 84 publications

(52 citation statements)

References 187 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, ferrospinels can be regarded as bi‐functional systems, which is derived from the presence of both redox and acid/base properties. Indeed, the MnFe 2 O 4 spinel was employed as a catalyst for CO 2 reduction, steam reforming of ethanol, catalytic ozonation, dehydrogenation of ethylbenzene to styrene, the Fenton reaction, vapor‐phase methylation of pyridine with methanol, and as a magnetically separable catalyst for biologically relevant 2‐substituted benzimidazoles and quinoxalines, etc. Besides the traditional applications, manganese ferrite showed good performance as an adsorbent for the removal of pollutants such as Congo red, Cr VI , Pb II , and azo dye Acid Red B (ARB) from water, it has also been successfully used as a material for “pure hydrogen” production in low‐temperature water splitting thermochemical cycles .…”

Section: Introductionmentioning

confidence: 99%

Structural Changes of Binary/Ternary Spinel Oxides During Ethanol Anaerobic Decomposition

et al. 2017

View full text Add to dashboard Cite

Several M‐modified iron oxides of the spinel family have proven to be effective electron and O2− vectors for the production of hydrogen in the chemical‐loop reforming of bio‐alcohols. The present work is specifically focused on investigation of ethanol anaerobic decomposition over spinel oxides, which results in significant structural changes of the oxygen carrier material itself and corresponds to a first step of the chemical‐loop reforming process. In particular, a series of binary/ternary M‐modified ferrospinels were prepared by a co‐precipitation method and tested in terms of both redox properties and intrinsic catalytic activity in addition to a complex ex situ study that encompasses the solid‐state chemistry investigations of the fresh and reduced oxygen carrier materials. It was found that Co/Cu incorporation facilitates total/partial oxidation of ethanol, giving rise to high yields of H2, COx, and H2O; whereas Mn incorporation predominantly favored dehydrogenation and condensation reactions, leading to the formation of acetaldehyde and acetone. In addition, the incorporation of Mn contributed to significantly reduce the amount of coke formed; however, it caused a lower intrinsic reducibility, which was explained by the formation of a thermodynamically stable and hardly reducible layer of MnxFeyO solid solution.

show abstract

Section: Introductionmentioning

confidence: 99%

Structural Changes of Binary/Ternary Spinel Oxides During Ethanol Anaerobic Decomposition

et al. 2017

View full text Add to dashboard Cite

show abstract

“… 8 POMs have attracted great attention in recent decades for their unique structural properties 9 and potential application in a number of fields, including medicine, 10 catalysis, 11 and materials chemistry. 12 More recently, examples of POMs being used as high-density electron storage media have been reported, revealing the potential use for these compounds in the growing global need for easily accessible energy storage. 13 By combining metal–oxo moieties with heteroanions, such as SO 4 2– , PO 4 3– , and AsO 4 3– , and transition-metal ions, such as Co 2+ , Fe 3+ , etc., the stability and structural diversity of the clusters is increased.…”

Section: Introductionmentioning

confidence: 99%

A Modular Programmable Inorganic Cluster Discovery Robot for the Discovery and Synthesis of Polyoxometalates

et al. 2020

View full text Add to dashboard Cite

The exploration of complex multicomponent chemical reactions leading to new clusters, where discovery requires both molecular self-assembly and crystallization, is a major challenge. This is because the systematic approach required for an experimental search is limited when the number of parameters in a chemical space becomes too large, restricting both exploration and reproducibility. Herein, we present a synthetic strategy to systematically search a very large set of potential reactions, using an inexpensive, high-throughput platform that is modular in terms of both hardware and software and is capable of running multiple reactions with in-line analysis, for the automation of inorganic and materials chemistry. The platform has been used to explore several inorganic chemical spaces to discover new and reproduce known tungsten-based, mixed transition-metal polyoxometalate clusters, giving a digital code that allows the easy repeat synthesis of the clusters. Among the many species identified in this work, the most significant is the discovery of a novel, purely inorganic W 24 Fe III –superoxide cluster formed under ambient conditions. The modular wheel platform was employed to undertake two chemical space explorations, producing compounds 1 – 4 : (C 2 H 8 N) 10 Na 2 [H 6 Fe(O 2 )W 24 O 82 ] ( 1 , {W 24 Fe}), (C 2 H 8 N) 72 Na 16 [H 16 Co 8 W 200 O 660 (H 2 O) 40 ] ( 2 , {W 200 Co 8 }), (C 2 H 8 N) 72 Na 16 [H 16 Ni 8 W 200 O 660 (H 2 O) 40 ] ( 3 , {W 200 Ni 8 }), and (C 2 H 8 N) 14 [H 26 W 34 V 4 O 130 ] ( 4 , {W 34 V 4 }), along with many other known species, such as simple Keggin clusters and 1D {W 11 M 2+ } chains.

show abstract

“…[ 9,10 ] Polyoxometalates (POMs) recently emerged as promising inorganic materials due to their varying structures, high electrochemical activities, and EC performances. [ 11,12 ] The most common and widely investigated POM structure is the Keggin structure, which is applied in biochemical, electrochemical, and catalytic areas. [ 13 ] However, studies on the EC properties of Keggin‐structured POMs are limited, and their reported EC performances were inferior to other POM types.…”

Section: Introductionmentioning

confidence: 99%

Charge‐Balancing Redox Mediators for High Color Contrast Electrochromism on Polyoxometalates

Wang

et al. 2020

Adv Materials Technologies

Self Cite

View full text Add to dashboard Cite

POMs) recently emerged as promising inorganic materials due to their varying structures, high electrochemical activities, and EC performances. [11,12] The most common and widely investigated POM structure is the Keggin structure, which is applied in biochemical, electrochemical, and catalytic areas. [13] However, studies on the EC properties of Keggin-structured POMs are limited, and their reported EC performances were inferior to other POM types. [14] Several attempts were made to improve the EC performance, including modifying the molecular structure or atomic composition, and optimizing the nanostructures [15-19] Notably, for POM-based EC materials, these approaches were employed by simultaneously selecting and controlling their nanostructures. Porous TiO 2 nanoparticle films (TNFs) are successful POMs' hosts displaying satisfactory EC performances due to their large specific surface area and porous morphology. [20-23] Further increases in ΔT were obtained by assisting the EC reaction by charge-balancing species between the working and counter electrodes in a full cell structure. Although some full cell type ECDs were achieved with POMs, [20,23] charge-balancing reactions were rarely examined, possibly because of the complicated EC mechanism, which makes it difficult to select CBMs for POMs. To create a CBM, a redox active material or electron reservoir was coated on the counter electrode (film type) or dissolved in the electrolyte (solution type). To simplify the ECD structure and avoid increasing its thickness, the solution type could be promising for high-performance ECDs. For example, a WO 3-based ECD showed enhanced EC performance when it was assembled with an electrolyte containing a tetramethylthiourea redox couple. [24,25] Similarly, viologen-based ECDs displayed fast switching times and high cycling stability in the presence of an I − /I 3 − redox mediator in a gelatin-electrolyte. [26,27] However, POM-based ECDs with redox couples in the electrolyte are not reported in literature. Noticeably, POM-based ECDs suffer from limited electrolyte choices and low optical contrast (ΔT), and POM-based EC films are mainly operated in aqueous media. [28] Also, the limited electrochemical window (1.23 V) of the aqueous electrolyte restricted their broader application in ECDs. [29] In general, water can be electrolyzed, but generates bubbles at the voltage range for coloration and bleaching of EC materials. In a A nonaqueous charge-balancing electrolyte with a redox couple (I − /I 3 −) is investigated to improve the electrochromic (EC) performance of polyoxometalate (POM)-based electrochromic devices (ECDs). PW 12 O 40 3− (PW 12)-coated porous TiO 2 nanoparticle films (PWTNF) with different thicknesses are used as the working electrode. The optical contrast (ΔT) of the optimized PW 12-ECDs reached 59.4% with the electrolyte containing the I − /I 3 − redox couple. PW 12-ECDs also show a fast response time for bleaching (t b,90% = 1.9 s) and coloration (t c,90% = 3.1 s). On the contrary, without the I − /I 3 − redox ...

show abstract

Polyoxometalates as promising materials for electrochromic devices

Abstract: A comprehensive review on polyoxometalate-based electrochromic materials and their applications in electrochromic devices.

Cited by 84 publications

References 187 publications

Structural Changes of Binary/Ternary Spinel Oxides During Ethanol Anaerobic Decomposition

Structural Changes of Binary/Ternary Spinel Oxides During Ethanol Anaerobic Decomposition

A Modular Programmable Inorganic Cluster Discovery Robot for the Discovery and Synthesis of Polyoxometalates

Charge‐Balancing Redox Mediators for High Color Contrast Electrochromism on Polyoxometalates

Contact Info

Product

Resources

About