32767-18-3Relevant articles and documents
Oxysulfide photocatalyst for visible-light-driven overall water splitting
Wang, Qian,Nakabayashi, Mamiko,Hisatomi, Takashi,Sun, Song,Akiyama, Seiji,Wang, Zheng,Pan, Zhenhua,Xiao, Xiong,Watanabe, Tomoaki,Yamada, Taro,Shibata, Naoya,Takata, Tsuyoshi,Domen, Kazunari
, p. 827 - 832 (2019)
Oxysulfide semiconductors have narrow bandgaps suitable for water splitting under visible-light irradiation, because the electronegative sulfide ions negatively shift the valence band edges of the corresponding oxides1,2. However, the instability of sulfide ions during the water oxidation is a critical obstacle to simultaneous evolution of hydrogen and oxygen3. Here, we demonstrate the activation and stabilization of Y2Ti2O5S2, with a bandgap of 1.9 eV, as a photocatalyst for overall water splitting. On loading of IrO2 and Rh/Cr2O3 as oxygen and hydrogen evolution co-catalysts, respectively, and fine-tuning of the reaction conditions, simultaneous production of stoichiometric amounts of hydrogen and oxygen was achieved on Y2Ti2O5S2 during a 20 h reaction. The discovery of the overall water splitting capabilities of Y2Ti2O5S2 extends the range of promising materials for solar hydrogen production.
Photoinduced catalytic reaction by a fluorescent active cryptand containing an anthracene fragment
Hao, Hong-Guo,Zheng, Xiao-Dan,Lu, Tong-Bu
, p. 8148 - 8151 (2010)
Tripping the light fantastic: A fluorescently active cryptand containing an anthracene fragment catalyzes the photoinduced reduction of CuII to CuI with simultaneous oxidation of water to oxygen (see scheme).
Oxygen Vacancy Structure Associated Photocatalytic Water Oxidation of BiOCl
Li, Hao,Shang, Jian,Zhu, Huijun,Yang, Zhiping,Ai, Zhihui,Zhang, Lizhi
, p. 8276 - 8285 (2016)
A central issue in understanding photocatalytic water splitting on a stoichiometric or defective nanostructured oxide surface is its adsorption mode and related reactivity. More than just improving the adsorption of water on oxide surfaces, we demonstrate in this work that surface oxygen vacancies (OVs) also offer a possibility of activating water toward thermodynamically enhanced photocatalytic water oxidation, while the water activation state, as reflected by its capability to trap holes, strongly depends on the structures of OVs. Utilizing well-ordered BiOCl single-crystalline surfaces, we reveal that dissociatively adsorbed water on the OV of the (010) surface exhibits higher tendency to be oxidized than the molecularly adsorbed water on the OV of the (001) surface. Analysis of the geometric atom arrangement shows that the OV of the BiOCl (010) surface can facilitate barrierless O-H bond breaking in the first proton removal reaction, which is sterically hindered on the OV of the BiOCl (001) surface, and also allow more localized electrons transfer from the OV to the dissociatively adsorbed water, leading to its higher water activation level for hole trapping. These findings highlight the indispensable role of crystalline surface structure on water oxidation and may open up avenues for the rational design of highly efficient photocatalysts via surface engineering. (Chemical Equation Presented).
Mechanisms of water oxidation catalyzed by the cis,cis-[(bpy) 2Ru(OH2)]2O4+ ion
Yamada, Hiroshi,Siems, William F.,Koike, Tohru,Hurst, James K.
, p. 9786 - 9795 (2004)
The cis,cis-[(bpy)2RuIII(OH2)] 2O4+ μ-oxo dimeric coordination complex is an efficient catalyst for water oxidation by strong oxidants that proceeds via intermediary formation of cis,cis-[(bpy)2RuV(O)]2O 4+ (hereafter, {5,5}). Repetitive mass spectrometric measurement of the isotopic distribution of O2 formed in reactions catalyzed by 18O-labeled catalyst established the existence of two reaction pathways characterized by products containing either one atom each from a ruthenyl O and solvent H2O or both O atoms from solvent molecules. The apparent activation parameters for μ-oxo ion-catalyzed water oxidation by Ce4+ and for {5,5} decay were nearly identical, with ΔH? = 7.6 (±1.2) kcal/mol, ΔS? = -43 (±4) cal/deg mol (23 °C) and ΔH? = 7.9 (±1.1) kcal/mol, ΔS? = -44 (±4) cal/deg mol, respectively, in 0.5 M CF3SO3H. An apparent solvent deuterium kinetic isotope effect (KIE) of 1.7 was measured for O2 evolution at 23 °C; the corresponding KIE for {5,5} decay was 1.6. The 32O2/ 34O2 isotope distribution was also insensitive to solvent deuteration. On the basis of these results and previously established chemical properties of this class of compounds, mechanisms are proposed that feature as critical reaction steps H2O addition to the complex to form covalent hydrates. For the first pathway, the elements of H2O are added as OH and H to the adjacent terminal ruthenyl O atoms, and for the second pathway, OH is added to a bipyridine ring and H is added to one of the ruthenyl O atoms.
Mechanistic interpretation of CO oxidation turnover rates on supported Au clusters
Ojeda, Manuel,Zhan, Bi-Zeng,Iglesia, Enrique
, p. 92 - 102 (2012)
Kinetic and isotopic data are used to interpret the mechanistic role of gaseous H2O molecules and of non-reducible (Al2O 3) and reducible (TiO2, Fe2O3) supports on CO oxidation turnovers catalyzed by small Au clusters (2O acts as a co-catalyst essential for O2 activation and for catalyst stability in CO oxidation at near-ambient temperatures, but also inhibits rates via competitive adsorption at higher H2O pressures. The effects of CO, O2, and H2O pressures on CO oxidation turnover rates, the absence of 16O2/18O 2 and 16O2/H218O exchange, and the small H2O/D2O kinetic isotope effects are consistent with quasi-equilibrated molecular adsorption of CO, O 2, and H2O on Au clusters with the kinetic relevance of H2O-mediated O2 activation via the formation of hydroperoxy intermediates (OOH), which account for the remarkable reactivity and H2O effects on Au clusters. These elementary steps proceed on Au clusters without detectable requirements for support interface sites, which are no longer required when H2O is present and mediates O2 activation steps. Rate enhancements by H2O were also observed for CO oxidation on Pt clusters (1.3 nm), which is also limited by O2 activation steps, suggesting H2O-aided O2 activation and OOH species in oxidations involving kinetically-relevant O2 activation. These intermediates have also been proposed to account for the ability of O2/H2O mixtures to act as reactants in alkene epoxidation on Au-based catalysts.
Dual function photocatalysis of cyano-bridged heteronuclear metal complexes for water oxidation and two-electron reduction of dioxygen to produce hydrogen peroxide as a solar fuel
Aratani, Yusuke,Suenobu, Tomoyoshi,Ohkubo, Kei,Yamada, Yusuke,Fukuzumi, Shunichi
, p. 3473 - 3476 (2017)
The photocatalytic production of hydrogen peroxide from water and dioxygen under visible light irradiation was made possible by using polymeric cyano-bridged heteronuclear metal complexes (MII[RuII(CN)4(bpy)]; MII = NiII, FeII and MnII), where the photocatalytic two-electron reduction of O2 and water oxidation were catalysed by the Ru and MII moieties, respectively.
Structure-function relationships for electrocatalytic water oxidation by molecular [Mn12O12] clusters
Yan, Yong,Lee, John S.,Ruddy, Daniel A.
, p. 4550 - 4555 (2015)
A series of Mn12O12(OAc)16-xLx(H2O)4 molecular clusters (L = acetate, benzoate, benzenesulfonate, diphenylphosphonate, dichloroacetate) were electrocatalytically investigated as water oxidation electrocatalysts on a fluorine-doped tin oxide glass electrode. Four of the [Mn12O12] compounds demonstrated water oxidation activity at pH 7.0 at varying overpotentials (640-820 mV at 0.2 mA/cm2) and with high Faradaic efficiency (85-93%). For the most active complex, more than 200 turnovers were observed after 5 min. Two structure-function relationships for these complexes were developed. First, these complexes must undergo at least one-electron oxidation to become active catalysts, and complexes that cannot be oxidized in this potential window were inactive. Second, a greater degree of distortion at Mn1 and Mn3 centers correlated with higher catalytic activity. From this distortion analysis, either or both of these two Mn centers are proposed to be the catalytically active site.
Characterization of the O2-evolving reaction catalyzed by [(terpy)(H2O)MnIII(O)2MnIV (OH2(terpy)](NO3)3 (terpy = 2,2′:6,2″-terpyridine)
Limburg,Vrettos,Chen,De Paula,Crabtree,Brudvig
, p. 423 - 430 (2001)
The complex [(terpy)(H2O)MnIII(O)2MnlV (OH2)(terpy)](NO3)3 (terpy = 2,2′:6,2″-terpyridine) (1) catalyzes O2 evolution from either KHSO5 (potassium oxone) or NaOC1. The reactions follow Michaelis-Menten kinetics where Vmax = 2420 ± 490 mol O2 (mol 1)-1 hr-1 and Km = 53 ± 5 mM for oxone ([1] = 7.5 μM), and Vmax = 6.5 ± 0.3 mol O2 (mol 1)-1 hr-1 and KM = 39 ± 4 mM for hypochlorite ([1] = 70 μM), with first-order kinetics observed in 1 for both oxidants. A mechanism is proposed having a preequilibrium between 1 and HSO5- or OCI-, supported by the isolation and structural characterization of [(terpy)-(SO4)MnIV(O)2MnlV (O4S)(terpy)] (2). Isotope-labeling studies using H218O and KHS16O5 show that O2 evolution proceeds via an intermediate that can exchange with water, where Raman spectroscopy has been used to confirm that the active oxygen of HSO5- is nonexchanging (t1/2 ? 1 h). The amount of label incorporated into O2 is dependent on the relative concentrations of oxone and 1.32O2:34O2:36 O2 is 91.9 ± 0.3:7.6 ± 0.3:0.51 ± 0.48, when [HSO5-] = 50 mM (0.5 mM 1), and 49 ± 21:39 ± 15:12 ± 6 when [HSO5-] = 15 mM (0.75 mM 1). The rate-limiting step of O2 evolution is proposed to be formation of a formally MnV=O moiety which could then competitively react with either oxone or water/hydroxide to produce O2. These results show that 1 serves as a functional model for photosynthetic water oxidation.
Sustained water oxidation photocatalysis by a bioinspired manganese cluster
Brimblecombe, Robin,Swiegers, Gerhard F.,Dismukes, G. Charles,Spiccia, Leone
, p. 7335 - 7338 (2008)
(Chemical Equation Presented) The generation game: A manganese-oxo complex with a cubic {Mn4O4}7+ core catalyzes the electrooxidation of water when suspended within the aqueous channels of a Nafion membrane (see picture). Illumination with visible light under an applied potential of 1.0 V (vs Ag/AgCl) generates current over one thousand turnovers. The catalytically active species arises from photolysis and subsequent dissociation of the manganese complex.
Visible light water oxidation using a Co-catalyst loaded anatase-structured Ti1-(5 x /4)NbxO2-y-δNy compound
Breault, Tanya M.,Brancho, James J.,Guo, Ping,Bartlett, Bart M.
, p. 9363 - 9368 (2013)
The photocatalytic activity of anatase-structured Ti 1-(5x/4)NbxO2-y-δNy (x = 0.25, y = 0.02; NbN-25) was examined for water oxidation under UV and visible light irradiation. The semiconductor was prepared by sol-gel processing followed by nitridation in flowing ammonia and exhibits an indirect optical gap of 2.2 eV. Ti1-(5x/4)NbxO2-y-δNy was loaded with RuO2 by an impregnation technique, and optimized conditions reveal that 1 wt % RuO2 generates 16 μmol O2 from water with concomitant IO3- reduction after 3 h of illumination under simulated solar radiation at a flux of 600 mW/cm2 illumination, which corresponds to 6-sun AM1.5G illumination (compared to no detectible O2 without the RuO2 cocatalyst). A series of cut-on filters shows that the catalyst-loaded semiconductor evolves O 2 for λ ≤ 515 nm, and a gas-phase mass spectrometry isotope labeling experiment shows that irradiating an iodate solution in H 218O in the presence of 1 wt % RuO2 loaded on NbN-25 gives rise to catalytic water oxidation: both 36O2 and 34O2 are observed. It is unclear whether 16O arises from IO3- or surface reconstruction on the photocatalyst, but ICP-AES analysis of the postirradiated solution shows no dissolved metal ions.
Morphology-Controlled Self-Assembly and Nanostructured NiO: An Efficient and Robust Photocatalytic Water-Oxidation Catalyst
Du, Xiaoqiang,Ding, Yong,Li, Chengqiang
, p. 2370 - 2376 (2015)
Three α-NiO nanocompounds of different morphology, with nanorods, nanowires, and nanoplates, were synthesized by controlling the ratio of reactants and temperature. The shape and structure of the nanocompounds were confirmed by SEM, XRD, FTIR, Raman spectroscopy, energy-dispersive X-ray spectroscopy, BET, and X-ray photoelectron spectroscopy (XPS) analysis. These compounds were examined as catalysts in photocatalytic water oxidation with [Ru(2,2′-bipyridine)3]2+ and S2O82- as a photosensitizer and a sacrificial oxidant, respectively. All of the samples exhibit high turnover frequencies and perfect stability in slightly alkaline conditions. A characteristic peak at around E=0.95 V versus Ag/AgCl assigned to a Ni3+ species was detected by cyclic voltammetry, which suggests that a high-valent nickel species may be responsible for water oxidation. The surface properties of the α-NiO nanorods also remain unchanged after examination by XPS before and after the photocatalytic reaction.
Characterization of a Dinuclear MnV=O Complex and Its Efficient Evolution of O2 in the Presence of Water
Shimazaki, Yuichi,Nagano, Taro,Takesue, Hironori,Ye, Bao-Hui,Tani, Fumito,Naruta, Yoshinori
, p. 98 - 100 (2004)
A high valent MnV=O porphyrin dimer is prepared by peracid oxidation or an MnIII dimer under basic conditions at room temperature (see scheme; mCPBA = m-chloroperbenzoic acid). The addition of an acid to a solution of the MnV=O complex results in quantitative dioxygen evolution. Water and/or hydroxide ions are the sources of both the oxo ligand and the evolved dioxygen.
Resonance Raman evidence for the interconversion between an [Fe(III)-η1-OOH]2+ and [Fe(III)-η2-O2]+ species and mechanistic implications thereof
Ho, Raymond Y. N.,Roelfes, Gerard,Hermant, Roel,Hage, Ronald,Feringa, Ben L.,Que Jr., Lawrence
, p. 2161 - 2162 (1999)
The deprotonation of [Fe(III)(N4Py)(η1-OOH)]2+ 1 gives [Fe(III)(N4Py)(η2-OO)]+ 2, as unequivocally demonstrated by resonance Raman spectroscopy, and leads to the loss of alkane hydroxylation activity by 1.
Pathways of water oxidation catalyzed by ruthenium "blue dimers" characterized by18O-lsotopic labeling
Cape, Jonathan L.,Siems, William F.,Hurst, James K.
, p. 8729 - 8735 (2009)
Earlier 18O-H2O labeling studies had indicated that two concurrent pathways may exist for water oxidation catalyzed by [Ru(bpy) 2(OH2)]2O4+, aμ-oxo bridged diruthenium complex known colloqu
Evidence of Mars-Van-Krevelen Mechanism in the Electrochemical Oxygen Evolution on Ni-Based Catalysts
Dionigi, Fabio,Ferreira de Araújo, Jorge,Merzdorf, Thomas,Oh, Hyung-Suk,Strasser, Peter
, p. 14981 - 14988 (2021)
Water oxidation is a crucial reaction for renewable energy conversion and storage. Among the alkaline oxygen evolution reaction (OER) catalysts, NiFe based oxyhydroxides show the highest catalytic activity. However, the details of their OER mechanism are still unclear, due to the elusive nature of the OER intermediates. Here, using a novel differential electrochemical mass spectrometry (DEMS) cell interface, we performed isotope-labelling experiments in 18O-labelled aqueous alkaline electrolyte on Ni(OH)2 and NiFe layered double hydroxide nanocatalysts. Our experiments confirm the occurrence of Mars-van-Krevelen lattice oxygen evolution reaction mechanism in both catalysts to various degrees, which involves the coupling of oxygen atoms from the catalyst and the electrolyte. The quantitative charge analysis suggests that the participating lattice oxygen atoms belong exclusively to the catalyst surface, confirming DFT computational hypotheses. Also, DEMS data suggest a fundamental correlation between the magnitude of the lattice oxygen mechanism and the faradaic efficiency of oxygen controlled by pseudocapacitive oxidative metal redox charges.
Room Temperature Aerobic Peroxidation of Organic Substrates Catalyzed by Cobalt(III) Alkylperoxo Complexes
Chen, Yunzhou,Shi, Huatian,Lee, Chi-Sing,Yiu, Shek-Man,Man, Wai-Lun,Lau, Tai-Chu
supporting information, p. 14445 - 14450 (2021/09/18)
Room temperature aerobic oxidation of hydrocarbons is highly desirable and remains a great challenge. Here we report a series of highly electrophilic cobalt(III) alkylperoxo complexes, CoIII(qpy)OOR supported by a planar tetradentate quaterpyridine ligand that can directly abstract H atoms from hydrocarbons (R′H) at ambient conditions (CoIII(qpy)OOR + R′H → CoII(qpy) + R′?+ ROOH). The resulting alkyl radical (R′?) reacts rapidly with O2to form alkylperoxy radical (R′OO?), which is efficiently scavenged by CoII(qpy) to give CoIII(qpy)OOR′ (CoII(qpy) + R′OO?→ CoIII(qpy)OOR′). This unique reactivity enables CoIII(qpy)OOR to function as efficient catalysts for aerobic peroxidation of hydrocarbons (R′H + O2→ R′OOH) under 1 atm air and at room temperature.
Cobalt-Based Metal-Organic Cages for Visible-Light-Driven Water Oxidation
Chen, Zi-Ye,Li, Dan,Long, Zi-Hao,Wang, Xu-Sheng,Wang, Xue-Zhi,Zhou, Jie-Yi,Zhou, Xiao-Ping
, p. 10380 - 10386 (2021/07/21)
Water oxidation to molecular oxygen is indispensable but a challenge for splitting H2O. In this work, a series of Co-based metal-organic cages (MOCs) for photoinduced water oxidation were prepared. MOC-1 with both bis(μ-oxo) bridged dicobalt and Co-O (O from H2O) displays catalytic activity with an initial oxygen evolution rate of 80.4 mmol/g/h and a TOF of 7.49 × 10-3 s-1 in 10 min. In contrast, MOC-2 containing only Co-O (O from H2O) in the structure results in a lower oxygen evolution rate (40.8 mmol/g/h, 4.78 × 10-3 s-1), while the amount of oxygen evolved from the solution of MOC-4 without both active sites is undetectable. Isotope experiments with or without H218O as the reactant successfully demonstrate that the molecular oxygen was produced from water oxidation. Photophysical and electrochemical studies reveal that photoinduced water oxidation initializes via electron transfer from the excited [Ru(bpy)3]2+? to Na2S2O8, and then, the cobalt active sites further donate electrons to the oxidized [Ru(bpy)3]3+ to drive water oxidation. This proof-of-concept study indicates that MOCs can work as potential efficient catalysts for photoinduced water oxidation.
