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Title: One- or two-electron water oxidation, hydroxyl radical, or H 2O 2 evolution

Abstract

Electrochemical or photoelectrochemcial oxidation of water to form hydrogen peroxide (H 2O 2) or hydroxyl radicals (•OH) offers a very attractive route to water disinfection, and the first process could be the basis for a clean way to produce hydrogen peroxide. A major obstacle in the development of effective catalysts for these reactions is that the electrocatalyst must suppress the thermodynamically favored four-electron pathway leading to O 2 evolution. Here, we develop a thermochemical picture of the catalyst properties that determine selectivity toward the one, two, and four electron processes leading to •OH, H 2O 2, and O 2.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [4]
  1. Stanford Univ., Stanford, CA (United States)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States); Henan Univ. of Science and Technology, Luoyang (China)
  3. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  4. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1350735
Grant/Contract Number:
52454; AC02-76SF00515
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 8; Journal Issue: 6; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Siahrostami, Samira, Li, Guo -Ling, Viswanathan, Venkatasubramanian, and Nørskov, Jens K. One- or two-electron water oxidation, hydroxyl radical, or H2O2 evolution. United States: N. p., 2017. Web. doi:10.1021/acs.jpclett.6b02924.
Siahrostami, Samira, Li, Guo -Ling, Viswanathan, Venkatasubramanian, & Nørskov, Jens K. One- or two-electron water oxidation, hydroxyl radical, or H2O2 evolution. United States. doi:10.1021/acs.jpclett.6b02924.
Siahrostami, Samira, Li, Guo -Ling, Viswanathan, Venkatasubramanian, and Nørskov, Jens K. Thu . "One- or two-electron water oxidation, hydroxyl radical, or H2O2 evolution". United States. doi:10.1021/acs.jpclett.6b02924. https://www.osti.gov/servlets/purl/1350735.
@article{osti_1350735,
title = {One- or two-electron water oxidation, hydroxyl radical, or H2O2 evolution},
author = {Siahrostami, Samira and Li, Guo -Ling and Viswanathan, Venkatasubramanian and Nørskov, Jens K.},
abstractNote = {Electrochemical or photoelectrochemcial oxidation of water to form hydrogen peroxide (H2O2) or hydroxyl radicals (•OH) offers a very attractive route to water disinfection, and the first process could be the basis for a clean way to produce hydrogen peroxide. A major obstacle in the development of effective catalysts for these reactions is that the electrocatalyst must suppress the thermodynamically favored four-electron pathway leading to O2 evolution. Here, we develop a thermochemical picture of the catalyst properties that determine selectivity toward the one, two, and four electron processes leading to •OH, H2O2, and O2.},
doi = {10.1021/acs.jpclett.6b02924},
journal = {Journal of Physical Chemistry Letters},
number = 6,
volume = 8,
place = {United States},
year = {Thu Feb 23 00:00:00 EST 2017},
month = {Thu Feb 23 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 1work
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  • The oxidative degradation of acetaldehyde dimethyl acetal in dilute aqueous solutions has been studied kinetically by pulse radiolysis and with respect to product formation by both {gamma}-radiolysis and pulse radiolysis. In N{sub 2}O-saturated solutions, H abstraction from the substrate by the OH radical produces the radicals CH{sub 3}CH(OCH{sub 3})OCH{sub 2}{sup {sm bullet}} (1), CH{sub 2}C{sup {sm bullet}}(OCH{sub 3}){sub 2} (2), and {sup {sm bullet}}CH{sub 2}CH(OCH{sub 3}){sub 2} (3). Radicals 1 and 2 have reducing properties and react rapidly with tetranitromethane, yielding nitroform anion. Radical 3 is probably inert toward this compound on the pulse radiolysis time scale. While 1 formsmore » an adduct with an observable lifetime (k(dec) = 4.4 {times} 10{sup 4} s{sup {minus}1}), 2 gives rise to the immediate formation of nitroform anion. It has been estimated that the radicals are formed with G values of G(1) = 0.34, G(2) = 0.21, and G(3) {le} 0.02 {mu}mol J{sup {minus}1}. In N{sub 2}O/O{sub 2} (4:1, v/v) saturated solutions, the products are (G ({mu}mol J{sup {minus}1}) in parentheses) formaldehyde (0.16), methanol ({approx} 0.3), acetaldehyde (0.15), methyl acetate (0.21), formic acid (0.16), hydrogen peroxide (0.14), and organic hydroperoxide (0.19). As shown by pulse radiolysis, oxygen reacts with radicals 1-3 with a rate constant of k {ge} 2 {times} 10{sup 9} dm{sup 3} mol{sup {minus}1} s{sup {minus}1}, yielding (mainly) the peroxyl radicals CH{sub 3}CH(OCH{sub 3})OCH{sub 2}O{sub 2}{sup {sm bullet}} (4) and CH{sub 3}C(OCH{sub 3}){sub 2}O{sub 2}{sup {sm bullet}} (5). Peroxyl radical 5 cleaves off O{sub 2}{sup {sm bullet}{minus}} in a fast reaction (k = 6.5 {times} 10{sup 4} s{sup {minus}1}), which subsequently leads to the formation of methyl acetate and methanol.« less
  • [ital Ab] [ital initio] quantum mechanical self-consistent-field (SCF) and single and double excitation configuration interaction (CISD) methods have been used in a new study of hydrogen bonding between the water molecule and the hydroxyl radical. The basis sets used are double-zeta plus polarization (DZP) and triple-zeta plus double polarization (TZ2P). The two energetically low-lying minima are [sup 2][ital A][prime] and [sup 2][ital A][double prime] states, with hydrogen bonding occurring between the oxygen atom in the water molecule and the hydrogen atom in the hydroxyl radical; the [sup 2][ital A][prime] state has a slightly ([similar to]0.3 kcal/mol) lower energy. The comparablemore » planar [ital C][sub 2[ital v]] symmetry structure lies [lt]0.1 kcal/mol higher in energy. The hydrogen bond distance H...O of the [sup 2][ital A][prime] is [similar to]1.94 A, which is close to that of the water dimer. The ground state dissociation energy is 5.6 kcal/mol, which is larger than that of the water dimer. The predicted infrared spectra for these structures are also reported.« less
  • Two uranyl sulfate hydrates, (H3O)2[(UO2)2(SO4)3(H2O)]·7H2O (NDUS) and (H3O)2[(UO2)2(SO4)3(H2O)]·4H2O (NDUS1), and one uranyl selenate-selenite [C5H6N][(UO2)(SeO4)(HSeO3)] (NDUSe), were obtained and their crystal structures solved. NDUS and NDUSe result from reactions in highly acidic media in the presence of L-cystine at 373 K. NDUS crystallized in a closed vial at 278 K after 5 days and NDUSe in an open beaker at 278 K after 2 weeks. NDUS1 was synthesized from aqueous solution at room temperature over the course of a month. NDUS, NDUS1, and NDUSe crystallize in the monoclinic space group P21/n, a = 15.0249(4) Å,b = 9.9320(2) Å, c = 15.6518(4)more » Å, β = 112.778(1)°, V = 2153.52(9) Å3,Z = 4, the tetragonal space group P43212, a = 10.6111(2) Å,c = 31.644(1) Å, V = 3563.0(2) Å3, Z = 8, and in the monoclinic space group P21/n, a = 8.993(3) Å, b = 13.399(5) Å, c = 10.640(4) Å,β = 108.230(4)°, V = 1217.7(8) Å3, Z = 4, respectively.The structural units of NDUS and NDUS1 are two-dimensional uranyl sulfate sheets with a U/S ratio of 2/3. The structural unit of NDUSe is a two-dimensional uranyl selenate-selenite sheets with a U/Se ratio of 1/2. In-situ reaction of the L-cystine ligands gives two distinct products for the different acids used here. Where sulfuric acid is used, only H3O+ cations are located in the interlayer space, where they balance the charge of the sheets, whereas where selenic acid is used, interlayer C5H6N+ cations result from the cyclization of the carboxyl groups of L-cystine, balancing the charge of the sheets.« less
  • ((n-C{sub 4}H{sub 9}){sub 4}N){sub 5}Na{sub 3}((1,5-COD)Ir{center dot}P{sub 2}W{sub 15}Nb{sub 3}O{sub 62}), 1, ((n-C{sub 4}H{sub 9}){sub 4}N){sub 5}Na{sub 3}((1,5-COD)Rh{center dot}P{sub 2}W{sub 15}Nb{sub 3}O{sub 62}), and ((n-C{sub 4}H{sub 9}){sub 4}N){sub 4.5}Na{sub 2.5}((C{sub 6}H{sub 6})Ru{center dot}P{sub 2}W{sub 15}Nb{sub 3}O{sub 62}) have been shown to catalyze the oxygenation of cyclohexene with molecular oxygen. The polyoxoanion-supported iridium (I) complex, 1, shows the highest activity of this group with a turnover frequency of 2.9 h{sup {minus}1} at 38{degree}C in CH{sub 2}Cl{sub 2} (540 total turnovers), which is 100-fold greater than its parent iridium compound, ((1,5-COD)IrCl){sub 2}. Additional experiments using H{sub 2}/O{sub 2} mixtures and H{sub 2}O{submore » 2} are also discussed. The apparent rate law for the oxidation of cyclohexene by O{sub 2} by 1 is -d(cyclohexene)/dt = k{sub 2} obsd {center dot} (1){sup 1}(cyclohexene){sup 1}P(O{sub 2}){sup 1{yields}0}. These compounds constitute the first examples of oxygenation catalysis using molecular oxygen and a polyoxoanion-supported transition-metal precatalyst.« less