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7722-84-1Relevant academic research and scientific papers
Kinetics and mechanism of O-O bond cleavage in the reaction of [Ru III(edta)(H2O)]- with hydroperoxides in aqueous solution
Chatterjee, Debabrata,Sikdar, Anindita,Patnam, Vidya R.,Theodoridis, Alexander,Van Eldik, Rudi
, p. 3851 - 3856 (2008)
The reactions of [RuIII(edta)(H2O)]- (1) (edta = ethylenediaminetetraacetate) with tert-butylhydroperoxide ( tBuOOH) and potassium hydrogenpersulfate (KHSO5) were studied kinetically as a function of oxidant concentration and temperature (10-30 °C) at a fixed pH of 6.1 using stopped-flow techniques. Kinetic results were analyzed by using global kinetic analysis techniques. The reaction was found to consist of two steps involving the rapid formation of a [Ru III(edta)(OOR)]2- intermediate, which subsequently undergoes heterolytic cleavage to form [(edta)RuV=O]-. Since [(edta)RuV=O]- was produced almost quantitatively in the reaction of 1 with the hydroperoxides tBuOOH and KHSO 5, the common mechanism is one of heterolytic scission of the O-O bond. The water soluble and easy to oxidize substrate 2,2′-azobis(3- ethylbenzithiazoline-6-sulfonate (ABTS), was employed to substantiate the mechanistic proposal. Reactions were carried out under pseudo-first order conditions for [ABTS] [hydroperoxide] ? [1], and were monitored as a function of time for the formation of the one-electron oxidation product ABTS+. The detailed suggested mechanism is consistent with the reported rate and activation parameters, and discussed in reference to the results reported for the reaction of [RuII(edta)(H 2O)]- with H2O2.
Synergistic Cocatalytic Effect of Carbon Nanodots and Co3O4 Nanoclusters for the Photoelectrochemical Water Oxidation on Hematite
Zhang, Peng,Wang, Tuo,Chang, Xiaoxia,Zhang, Lei,Gong, Jinlong
, p. 5851 - 5855 (2016)
Cocatalysis plays an important role in enhancing the activity of semiconductor photocatalysts for solar water splitting. Compared to a single cocatalyst configuration, a cocatalytic system consisting of multiple components with different functions may realize outstanding enhancement through their interactions, yet limited research has been reported. Herein we describe the synergistic cocatalytic effect between carbon nanodots (CDots) and Co3O4, which promotes the photoelectrochemical water oxidation activity of the Fe2O3 photoanode with a 60 mV cathodically shifted onset potential. The C/Co3O4-Fe2O3 photoanode exhibits a photocurrent density of 1.48 mA cm-2 at 1.23 V (vs. reversible hydrogen electrode), 78 % higher than that of the bare Fe2O3 photoanode. The slow reaction process on the single CoIII-OH site of the Co3O4 cocatalyst, oxidizing H2O to H2O2 with two photogenerated holes, could be accelerated by the timely H2O2 oxidation to O2 catalyzed on CDots.
Oxygen reduction reaction on carbon-supported CoSe2 nanoparticles in an acidic medium
Feng, Yongjun,He, Ting,Alonso-Vante, Nicolas
, p. 5252 - 5256 (2009)
We investigated the effect of CoSe2/C nanoparticle loading rate on oxygen reduction reaction (ORR) activity and H2O2 production using the rotating disk electrode and the rotating ring-disk electrode techniques. We prepared
Hierarchically porous few-layer porphyrinic carbon nanosheets formed by a VO: X-templating method for high-efficiency oxygen electroreduction
Kong,Mao,Wang,Lin,Bu,Feng
, p. 7305 - 7312 (2016)
A new vanadium oxide-templating synthesis strategy is used to synthesize porous few-layer porphyrinic carbon nanosheets (PPCNs) with highly efficient electrocatalytic activity for oxygen reduction reaction (ORR). Fe-porphyrin precursors were intercalated into V2O5 layers and directly transformed to carbon nanosheets after pyrolysis. Highly accessible porphyrinic Fe-N4 moieties embedded within few-layer carbon nanosheets with hierarchical porosity and high surface area (1600 m2 g-1) were obtained. The PPCNs were demonstrated as excellent non-precious metal catalysts for ORR in both alkaline and acidic media. Specifically, the PPCNs exhibited a more positive half-wave potential than commercial Pt/C (20 wt%) in an alkaline medium at a lower catalyst loading. Moreover through further pyrolysis treatment, the catalytic activity and durability of PPCNs for ORR in both media could be further improved. The novel synthesis method presented here opens up a new route to creating novel carbon nanomaterials for various applications.
Production of hydrogen peroxide from carbon monoxide, water and oxygen over alumina-supported Ni catalysts
Ma, Zhong-Long,Jia, Rong-Li,Liu, Chang-Jun
, p. 157 - 163 (2004)
Novel amorphous Ni-B catalysts supported on alumina have been developed for the production of hydrogen peroxide from carbon monoxide, water and oxygen. The experimental investigation confirmed that the promoter/Ni ratio and the preparation conditions have a significant effect on the activity and lifetime of the catalyst. Among all the catalysts tested, the Ni-La-B/γ-Al 2O3 catalyst with a 1:15 atomic ratio of La/Ni, dried at 120°C, shows the best activity and lifetime for the production of hydrogen peroxide. The deactivation of the alumina-supported Ni-B amorphous catalyst was also studied. According to the characterizations of the fresh and used catalysts by SEM, XRD and XPS, no sintering of the active component and crystallization of the amorphous species were observed. However, it is water poisoning that leads to the deactivation of the catalyst. The catalyst characterization demonstrated that the active component had changed (i.e., amorphous NiO to amorphous Ni(OH)2) and then salt was formed in the reaction conditions. Water promoted the deactivation because the surface transformation of the active Ni species was accelerated by forming Ni(OH) 2 in the presence of water. The formed Ni(OH)2 would partially change to Ni3(PO4)2.
Structural studies on manganese(III) and manganese(IV) complexes of tetrachlorocatechol and the catalytic reduction of dioxygen to hydrogen peroxide
Sheriff, Tippu S.,Carr, Pamela,Coles, Simon J.,Hursthouse, Michael B.,Lesin, Jocelyne,Light, Mark E.
, p. 2494 - 2502 (2004)
The mononuclear complexes (Bu4N)[Mn(Cl4Cat) 2(H2O)(EtOH)] and (Bu4N)2[Mn(Cl 4Cat)3] (H2Cat=1,2-dihydroxybenzene) have been synthesised and characterised by X-ray diffraction. This work provides a direct, independent, synthesis of these complexes and an interesting example of how solvent effects can promote the formation of either a manganese(III) or manganese(IV) complex of the same ligand. The characterisation of (Bu 4N)[Mn(Cl4Cat)2(H2O)(EtOH)] supports previous work that manganese(III) is extremely reluctant to form tris (catecholato) complexes due to the short 'bite distance' of catecholate oxygen atoms (2.79 ?) which are unable to span the elongated coordination axes of the Jahn-Teller distorted Mn(III) ion and explains the 2:1 and 3:1 tetrachlorocatechol:manganese ratios in the Mn(III) and Mn(IV) complexes, respectively. Hydrogen peroxide production using dioxygen and hydroxylamine as substrates in acetonitrile/water mixtures, under ambient conditions, can be demonstrated with both complexes, suggesting that neither labile coordination sites nor the oxidation state of the manganese are important to the catalytic system. Turn over frequencies (TOF, moles of H2O2 per moles of manganese per hour) of ～10000 h-1 are obtained and this compares very favourably with the commercial production of hydrogen peroxide by the autoxidation of 2-ethylanthrahydroquinone (AO process).
Porous Carbon-Hosted Atomically Dispersed Iron–Nitrogen Moiety as Enhanced Electrocatalysts for Oxygen Reduction Reaction in a Wide Range of pH
Fu, Shaofang,Zhu, Chengzhou,Su, Dong,Song, Junhua,Yao, Siyu,Feng, Shuo,Engelhard, Mark H.,Du, Dan,Lin, Yuehe
, (2018)
As one of the alternatives to replace precious metal catalysts, transition-metal–nitrogen–carbon (M–N–C) electrocatalysts have attracted great research interest due to their low cost and good catalytic activities. Despite nanostructured M–N–C catalysts can achieve good electrochemical performances, they are vulnerable to aggregation and insufficient catalytic sites upon continuous catalytic reaction. In this work, metal–organic frameworks derived porous single-atom electrocatalysts (SAEs) were successfully prepared by simple pyrolysis procedure without any further posttreatment. Combining the X-ray absorption near-edge spectroscopy and electrochemical measurements, the SAEs have been identified with superior oxygen reduction reaction (ORR) activity and stability compared with Pt/C catalysts in alkaline condition. More impressively, the SAEs also show excellent ORR electrocatalytic performance in both acid and neutral media. This study of nonprecious catalysts provides new insights on nanoengineering catalytically active sites and porous structures for nonprecious metal ORR catalysis in a wide range of pH.
Crystalline-Water/Coordination Induced Formation of 3D Highly Porous Heteroatom-Doped Ultrathin Carbon Nanosheet Networks for Oxygen Reduction Reaction
Liu, Tingting,Feng, Shi,Huo, Jia,Li, Qiling,Xie, Chao,Wang, Shuangyin
, p. 4562 - 4568 (2018)
Development of highly efficient electrocatalysts with low cost for oxygen reduction reaction (ORR) is crucial for their application in fuel cells and metal-air batteries. In this work, we report a synthesis of 3D heteroatom-doped ultrathin carbon nanosheet networks directly starting from solid raw materials. This method represents an operationally simple, general, and sustainable strategy to various ultrathin carbon nanosheet networks. Evaporation of crystalline water and coordination interaction are proposed to be responsible for the formation of the 3D carbon nanosheet networks. The carbon nanosheet networks possess high surface area with micro- and macropores, large pore volume, ultrathin nanosheet structure, and effective N/S-co-doping. The as-prepared materials show outstanding electrocatalytic ORR performance with more positive onset potential and half-wave potential, good methanol tolerance, and excellent stability, compared with those of the porous carbons derived from the ZIF counterpart and commercial Pt/C. This work not only provides highly active ORR electrocatalysts via an operationally simple and green process and also demonstrates a general method to prepare 3D ultrathin carbon nanosheet networks without any additional template and solvent.
Synthesis of hydrogen peroxide in a proton exchange membrane electrochemical reactor
Tatapudi,Fenton
, p. L55-L57 (1993)
Humidified oxygen was reduced to hydrogen peroxide at the cathode in a proton exchange membrane electrochemical flow reactor. The optimum conditions for peroxide generation were determined as a function of the applied voltage, electrode materials (gold, graphite, and activated carbon powders), catalyst loadings, reactant flowrates, and pressure. Measured and calculated quantities included cell current, peroxide concentrations, and current efficiencies.
Changes induced by transition metal oxides in Pt nanoparticles unveil the effects of electronic properties on oxygen reduction activity
Ometto, Felipe B.,Carbonio, Emilia A.,Teixeira-Neto, érico,Villullas, Hebe M.
, p. 2075 - 2086 (2019)
Although the relevance of electronic effects in the electrocatalysis of the oxygen reduction reaction has been recognized, the impossibility of separating the effects of composition and particle size for Pt-based materials has hindered establishing clear activity-property relationships. Herein, we report a systematic study based on induced changes via the interactions of pure Pt nanoparticles with transition metal oxide/carbon supports (Pt/MOx/C catalysts, MOx = CeO2, SnO2, TiO2, ZrO2 and WO3). A thorough analysis of aberration-corrected HR-STEM images demonstrated that Pt particles are similar in size and shape for all catalysts, while the direct probing of electronic properties by in situ X-ray absorption spectroscopy evidenced charge transfer between Pt and the supports. This approach allowed ascribing the changes in electrocatalytic activity for oxygen reduction solely to the variations in the electronic vacancy of the Pt 5d band resulting from the interactions between the metal nanoparticles and the supports containing different transition metal oxides. Oxygen reduction was studied in acid and in alkaline solutions, and linear correlations between the kinetic current densities and the Pt 5d band vacancy of pure Pt nanoparticles were found in both media. Possible first steps of the reduction of oxygen are discussed to explain the trends observed. The results, evidencing that enhanced ORR activity on Pt particles is promoted by a lower 5d band vacancy in acid solutions and by a higher one in alkaline medium, provide new insights on the fundamental aspects of oxygen reduction, and open up new possibilities to develop catalysts with enhanced activity for fuel cell cathodes by tuning their electronic properties.