Nitrate and Nitrite Electrocatalytic Reduction at Layer-by-Layer Films Composed of Dawson-type Heteropolyanions Mono-substituted with Transitional Metal Ions and Silver Nanoparticles

Polyoxometalates-Functionalized Electrodes for (Photo)Electrocatalytic Applications: Recent Advances and Prospects

“…These pioneered studies have revealed the electrochemical reduction of Keggin anions in acid solution, especially the polyoxotungstates [XW 12 O 40 ] n− with X = Si, B, and H 2 , can lead to the formation of a brownish six-electron reduced POMs that belong to the Robin−Day class I mixed-valence compounds. In contrast to the "heteropoly blues", the electrons within "heteropoly browns" appear located within three W−W bonds forming a W IV based triad that have been clearly evidenced by 183 W NMR studies and X-ray diffraction analysis. 80−83 Interestingly, the structural analysis revealed the terminal oxygen atoms of the electron-rich metal triad are diprotonated such as water molecules (Figure 4).…”

“…So, Keggin-, Dawson-, and crown-type POMs and their transition metal ion-substituted derivatives have been assembled with various cationic components, such as redox-active Ru­(II) metallodendrimers, metal-complexed porphyrins, or nonelectroactive polymer layers, to produce functional electrodes which were active for the electrocatalytic reduction of some oxyanionic species (e.g., nitrite), hydrogen peroxide reduction, or oxidation of methanol (Table ). − Compared with POMs-incorporating ECP films, such assemblies offer some benefits such as enhanced permeability, better robustness over electrochemical cycling, and better resistance against some interferents. Interestingly, the assembly with redox-active cationic complexes enabled extension of the electroactivity window of the functional electrodes window. − , Furthermore, additional incorporation of metal nanoparticles (e.g., Ag), denoted NPs hereafter, was found to be also beneficial for increasing the electronic conductivity of such assemblies. − …”

“… − Compared with POMs-incorporating ECP films, such assemblies offer some benefits such as enhanced permeability, better robustness over electrochemical cycling, and better resistance against some interferents. Interestingly, the assembly with redox-active cationic complexes enabled extension of the electroactivity window of the functional electrodes window. − , Furthermore, additional incorporation of metal nanoparticles (e.g., Ag), denoted NPs hereafter, was found to be also beneficial for increasing the electronic conductivity of such assemblies. − …”

Electrochemical properties of the [SiW10O36(M2O2Kemmegne‐Mbouguen1, Floquet2, Cadot3 2021Comptes Rendus. Chimie6000View full textAdd to dashboardCite

“…In particular, with a tremendously diverse variety of POMs capable of storing a high number of electrons and displaying proton transfer capabilities, this class of compounds behaves as very efficient electrocatalysts for reactions of environmental interest such as CO 2 reduction [20][21][22], proton reduction into hydrogen [23][24][25], oxygen evolution reaction [26][27][28][29], or detection of environmental pollutants like nitrogen oxides [30][31][32][33][34][35], bromates [35][36][37][38], or iodates [35,37,[39][40][41].…”

Performance eletrocatalítica frente a nitrito de um filme híbrido de fosfomolibdato e sílica organomodificada

“…Embora nitrito já tenha sido detectado eletroquimicamente por POMs suportados em diferentes matrizes [16,17,[22][23][24], o uso de ormosil como matriz de imobilização de POMs para posterior detecção de nitrito ainda não foi alvo de estudo. As principais razões para o estudo da detecção de nitrito surgem em decorrência do seu enorme uso na conservação de alimentos [25] e também ao fato de que seu consumo está relacionado com o desenvolvimento de tumores em humanos [26].…”