Insights into the spontaneous formation of hybrid PdO_x/PEDOT films: electroless deposition and oxygen reduction activity

Abstract

Hybrid palladium oxide/poly (3,4-ethylenedioxythiophene)

Nanoarchitectonics of metal organic frameworks and PEDOT layer-by-layer electrodes for boosting oxygen reduction reaction

“…In this regard, a wide variety of materials have been reported to decrease the ORR onset potential or enhance the 4electron mechanism when integrated to PEDOT-based electrodes, including CoMn 2 O 4 spinel nanorods, 41 reduced graphene oxide with Fe 3 O 4 nanorods 42 and Au nanoparticles, 43 graphene quantum dots, 44 hemin, 45 MnO x , 46 and PdO x. 47 Even, the integration of electrochemically inactive materials such as PEG-PDMS-PEG block copolymers within the PEDOT matrix has been reported to improve the ORR by modifying the conducting polymer structure and, thus, its electrocatalytic activity. 48 These kinds of strategies operate on the redox reaction mechanism of the ORR.…”

Perfluoro-Functionalized Conducting Polymers Enhance Electrocatalytic Oxygen Reduction

“…Several conducting polymers have been investigated as effective metal-free electrocatalysts for the ORR, including polypyrrole (PPy), , polyaniline (PANI), , and poly­(3,4-ethylenedioxythiophene) (PEDOT). , These polymers act not only as efficient ORR electrocatalysts but also as conductive supports (replacing the typically used carbon), as binders (replacing Nafion, the most commonly used material that accounts for almost 40% of the cost of the reaction cell), and as precursors for pyrolyzed M-N x /C catalysts. − PEDOT has received the most interest ever since Winther-Jensen observed its ability to catalyze the ORR . PEDOT is also used in many other electrochemical applications, including sensors, solar cells, organic light-emitting diodes, supercapacitors, and Li-ion batteries , because of its low cost, high electronic conductivity, good capacitive behavior, distinct redox properties, mechanical flexibility, and high chemical stability.…”

“…A high value of n leads to the production of H 2 O as the only byproduct (according to eq ) without any H 2 O 2 , thereby protecting the PEMFC from deterioration. The literature suggests that the ORR at a PEDOT surface proceeds through the two overall pathways (i) and (ii), depending upon several factors, including the polymerization method (electro-, chemical-, or vapor-phase polymerization), morphology, synthesis solvent, and presence of metal oxides. ,− ,,, For example, Abdelhamid et al revealed that the ORR proceeds through the two-electron or mixed reduction pathway in an alkaline electrolyte at PEDOT [polymerized from the ionic liquid 1-butyl-1-methylpyrrolidinium bis­(trifluoromethylsulfonyl)­imide (C4mpyrTFSI)] in a sandwich configuration on flexible carbon cloth electrodes ( n = 2.7) . Shi et al reported that the ORR proceeds through the two-electron pathway at PEDOT:PSS ( n = 2.0–2.2) .…”

“…Moreover, Zhang et al noted that the electron-transfer numbers for H 2 SO 4 -treated PEDOT:PSS/rGO composites were 3.3–3.8, significantly higher than those of PEDOT:PSS (2.0–2.2) and rGO (2.3–2.8) electrodes, the result of the increased conductivity of PEDOT and the further reduction of rGO by concentrated H 2 SO 4 . Furthermore, Vigil et al found that the incorporation of transition metal oxides (MnO x , PdO x ) into PEDOT polymers increased the preference of the four-electron pathway, as well as the ORR performance, due to improved conductivity and electron transport. − …”

“…The literature suggests that the ORR at a PEDOT surface proceeds through the two overall pathways (i) and (ii), depending upon several factors, including the polymerization method (electro-, chemical-, or vapor-phase polymerization), morphology, synthesis solvent, and presence of metal oxides. 15,[18][19][20]23,35,36 For example, Abdelhamid et al revealed that the ORR proceeds through the two-electron or mixed reduction pathway in an alkaline electrolyte at PEDOT [polymerized from the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (C4mpyrTFSI)] in a sandwich configuration on flexible carbon cloth electrodes (n = 2.7). 23 ) into PEDOT polymers increased the preference of the four-electron pathway, as well as the ORR performance, due to improved conductivity and electron transport.…”