Recent trends in the use of polyoxometalate-based material for efficient water oxidation

Abstract

Polyoxometalates (POMs), with their attractive topological and electronic properties, have been demonstrated over the last few decades to be efficient catalysts for many reactions. In a new direction, POMs having a purely inorganic framework are now being explored as efficient catalysts for water oxidation. This review focuses on very recent developments of POM-based catalysts for water oxidation to O 2 . In the very extensive family of POMs, tetra-core sandwich-type Ru-and Co-containing POM complexes, namely [Ru 4 O 4 (OH) 2 (H 2 O) 4 (-SiW 10 O 36 ) 2 ] 10 and [Co 4 (H 2 O) 2 (-PW 9 O 34 ) 2 ] 10 exhibit the ability to facilitate water oxidation under electrocatalytic and/or photocatalytic conditions. However, it is concluded that much work still needs to be done to explain the catalytic mechanisms and optimize these catalytic systems. In addition, recent trends in using ionic liquids as media to modify the electrolytic environment and enhance water oxidation are highlighted.

Rectification direction inversion in a phosphododecamolybdic acid/single-walled carbon nanotube junction

“…The PMo 12 molecules are most likely partially protonated by carboxylic acids formed on the surfaces or edges of the SWNTs, and atmospheric moisture, which has been reported for similar POM compounds. 36,37 We performed the I-V measurements of the PMo 12 /SWNT complex under different experimental conditions, which were shown in Fig. 7.…”

Synthesis and visible-light photochromism of a new composite based on magadiite containing polytungstate

“…28 Water was also oxidized to produce dioxygen and protons along with the concomitant reduction of the POM anion from [P 2 W 18 O 62 ] 6À to [P 2 W 18 O 62 ] 7À . 29 Similarly, excitation of the OMCT band of the polyoxotungstate cluster in the near UV-light region results in the charge transfer from an O 2À ion to a W 6+ ion occurring at W-O-W bonds, leading to the formation of a pair of a hole center (O À ) and trapped electron center (W 5+ ). 30 Based on water splitting by the photo-irradiation of polytungstates and the photochromic mechanism of other isopolytungstates, 28,31 species may be attributed to the transfer of a proton from the interlayer water molecules to the oxygen atom at the photoreducible site in the WO 6 octahedral lattice, which is similar to the mechanism of the transfer of a proton from the nitrogen of organic molecules to the bridge oxygen atom at the photoreducible site in the edge-shared MoO 6 octahedral lattice.…”

From China to the world: Science China Chemistry celebrates the International Year of Chemistry

“…Polyoxometalates (POMs) with a purely inorganic framework have been studied as potential efficient catalysts for water oxidation. Zhangang Han, Alan Bond, and Chuan Zhao reviewed recent work in using POM-modified electrodes for efficient catalytic water oxidation to form H 2 and O 2 gases as an energy source ( Figure 5) [17].…”

“…Surface-attached metal-organic frameworks (SURMOFs) are an important class of metal-organic framework (MOF) Figure 5 Graphic abstract of the review by Han, Bond, and Zhao [17]. films.…”

“…Since these papers have been discussed earlier, their potential applications are highlighted here. The review by Han, Bond and Zhao pointed one potential catalytic process using polyoxometalates (POMs) for water splitting into H 2 and O 2 gases as a potential clean, sustainable energy source [17]. Cheng and Hou's comment demonstrated the unique role that rare-earth dialkyl and dihydride complexes bearing monoanionic ancillary ligands play and their uses in catalytic polymerization of olefins [37].…”