Zwitterionic hydrogen-bonded organic framework (ZHOF): a metal-free water oxidation proton relay in alkaline and neutral media

Abstract

Graphite supported zwitterionic hydrogen-bonded organic framework (ZHOF) acts as a supercapacitor, and proton relay during water oxidation reactions in alkaline and natural media.

Oxygen Vacancy-Originated Inorganic Proton Relay for the Oxygen Evolution Reaction: Fast Proton Hopping via La-Doped Praseodymium Carbonate Hydroxide

“…The closeness of LSV measurements in Figure 4c explains how the presence of La dramatically diminishes the J value gap of the deutero and proteo solutions so that the KIE gets values lower than 1.5, a secondary KIE (SKIE), indicating no tangible O−H bond cleavage in the RDS of OER. 31,32,91 Further studies performed on NF/Mg-LaPrCH, NF/Ca-LaPrCH, and NF/Sr-LaPrCH show a slight change in KIE values upon doping with alkaline-earth metal ions (Figure 4d− f). As is obvious, the results of electrochemical measurements and XPS studies are matched well, in which the O 1s exhibits a more apparent percentage of the O V toward the O L in Ladoped samples, while the Sr doping possessed no significant change in χ (A V /A L ) values.…”

“…101 We already elucidated the role of G-type impedance in the mechanistic explication of the guanidinebased polymeric proton relay 32 and graphite sheet bearing zwitterionic hydrogen-bonded organic framework (ZHOF). 31 In Figure 6C, the Bode plot is presented, showing a descending linear segment that represents the contribution of Warburg behavior in the impedance data.…”

“…5,28−30 It is reported that these interfacial occurrences can boost O−O bond formation through refinement of concerted or nonconcerted PCET. 31,32 In this work, we experimentally studied how these surface events may regulate the proton translocation among the surface-anchored protonic species and the rate of the proton hopping mechanism. 5,28,28,31,33 Some theoretical studies explained how the localized electrons next to OV become delocalized to accelerate ET from the surface-anchored species to the current collector.…”

“…31,32 In this work, we experimentally studied how these surface events may regulate the proton translocation among the surface-anchored protonic species and the rate of the proton hopping mechanism. 5,28,28,31,33 Some theoretical studies explained how the localized electrons next to OV become delocalized to accelerate ET from the surface-anchored species to the current collector. 34−36 On this basis, Hirai et al hypothesized the O−O bond formation through a short distance of the hydroxyl groups coupled to the oxygen vacant sites.…”

Electrocatalytic oxygen evolution activity of surfactant-free cobalt- and manganese-based spinel oxide nanoparticles in acid

“…The non-zero dependence of the OER current on [H + ] suggests that for these electrodes, the OER mechanism involves a non-concerted proton coupled electron transfer (PCET) process. 45 The higher m H+ also indicates that the p K a of the Mn–OH or Mn–OH 2 center is higher than that of Co–OH or Co–OH 2 , and that the presence of Fe significantly increases the acidity of the metal center, possibly through electron interaction. It is well-accepted that the acidic OER mechanisms can be categorized into two different classes, the adsorbate evolution mechanism (AEM) and the lattice oxygen involved evolution mechanism (LOM).…”