Co-reporter:Jingwei Huang, Yan Zhang, and Yong Ding
ACS Catalysis March 3, 2017 Volume 7(Issue 3) pp:1841-1841
Publication Date(Web):February 3, 2017
DOI:10.1021/acscatal.7b00022
Water oxidation catalysts have been usually used to enhance the charge injection efficiency of WO3 anodes. Herein, we simultaneously improve the charge separation efficiency and charge injection efficiency, as well as the oxidation selectivity of WO3 for photoelectrochemical water oxidation by loading CoOx nanoparticles in a neutral electrolyte. The produced oxygen is monitored by a Clark electrode, which shows a high Faradaic efficiency on CoOx/WO3. In an effort to gain insight into the role of CoOx on the high Faradaic efficiency, the rotating ring–disk electrode system was used to detect the products of the CoOx/WO3 heterojunction in the photoelectrochemical water oxidation process. The results show that the loading of CoOx nanoparticles can improve oxidation selectivity of WO3 and therefore improve the Faradaic efficiency of WO3.Keywords: cobalt oxide; photoelectrochemical water oxidation; p−n junction; rotating ring−disk electrode; tungsten oxide;
Co-reporter:Xichen Zhou;Jingwei Huang;Fuming Zhang;Yukun Zhao;Yan Zhang
Dalton Transactions 2017 vol. 46(Issue 32) pp:10602-10610
Publication Date(Web):2017/08/14
DOI:10.1039/C7DT00302A
Cobalt-based oxides are considered as potential water oxidation catalysts for future artificial photosynthetic systems because of their high abundance, strong stability and efficient performance. Herein, a series of cobalt-based oxides, MnCo3−nO4 (M = Mn, Fe, Co) samples, were synthesized through changing the metal sources by a low-temperature coprecipitation method. These catalysts were investigated under photochemical and electrochemical water oxidation conditions. And they all exhibited efficient activity for water oxidation under alkaline, acidic and neutral conditions under visible light irradiation. An excellent O2 yield of 90.4% for Fe–Co bimetal oxide (Fe1.1Co1.9O4) nanorods was obtained under optimal conditions (photoirradiation at λ ≥ 420 nm, [Ru(bpy)3](ClO4)2 as the photosensitizer, Na2S2O8 as the oxidant in borate buffer at pH = 9.0, bpy = 2,2-bipyridine). Among MnCo3−nO4 samples, Fe1.1Co1.9O4 nanorods were proved to be the optimal electrocatalytic water oxidation catalyst as well. Multiple experiments (SEM, FT-IR, XRD, XPS, Bulk electrolysis) were used to test the stability of Fe1.1CO1.9O4 and these results indicate that Fe1.1CO1.9O4 nanorods are highly stable. Furthermore, based on Mott–Schottky and cyclic voltammetry analysis, the best balanced flat-band potential of Fe1.1CO1.9O4 nanorods is just located at the middle position between the oxidation potential of O2/H2O and the half-wave potential of [Ru(bpy)3]3+/2+, which was probably responsible for their superior photocatalytic water oxidation performance.
Co-reporter:Junqi Lin, Peng Kang, Xiangming Liang, Baochun Ma, Yong Ding
Electrochimica Acta 2017 Volume 258(Volume 258) pp:
Publication Date(Web):20 December 2017
DOI:10.1016/j.electacta.2017.11.061
•Three (Me4N)2[NiLi] complexes were first used as water oxidation electrocatalysts.•The mechanism of water oxidation reaction catalyzed by (Me4N)2[NiL1] was proposed.•A stability relationship between the molecular catalyst and ligand structure was obtained.Three nickel (II) complexes of o-phenylenebis(N′-methyloxamidate) (L1), o-phenylene(N′-methyloxamidate)oxamate (L2) and o-phenylenebis(oxamate) (L3) with tetradentate ligands are synthesized and characterized. These four-coordinate complexes, (Me4N)2[NiLi] (i = 1–3 for complex 1–3), are investigated for electrocatalytic water oxidation in basic phosphate buffer solution. Experimental results show that (Me4N)2[NiL1] (1) is a homogeneous catalyst for electrochemical water oxidation. However, under the same condition, 2 and 3 decompose into NiOx nanoparticles, which acts as precatalyst for the electrocatalytic water oxidation. The catalytic mechanism for electrocatalytic water oxidation by 1 is proposed using cyclic voltammetry experiments, kinetic isotope effect and Pourbaix diagram. By constructing the relationship between the molecular structure and stability of these catalysts, nitrogen atom is found to be more beneficial than carboxyl group for the stability of nickel based homogeneous electrochemical water oxidation catalysts.Electrochemical water oxidation catalyzed by a mononuclear homogeneous Ni complex at low over potential. Download high-res image (318KB)Download full-size image
Co-reporter:Beibei Zhang;Guojun Dong;Lei Wang;Yajun Zhang;Yingpu Bi
Catalysis Science & Technology (2011-Present) 2017 vol. 7(Issue 21) pp:4971-4976
Publication Date(Web):2017/10/30
DOI:10.1039/C7CY01765K
Photoelectrochemical (PEC) water splitting to produce hydrogen energy has attracted considerable attention for solving current energy and environmental crises. However, the intrinsically high electron–hole recombination and low charge mobility greatly diminish the PEC efficiency. Herein, we demonstrated that metal organic framework MIL-53(Fe) could serve as an efficient hole-transfer co-catalyst to significantly improve the PEC performance of Mo-doped BiVO4 photoanodes toward water oxidation under solar irradiation, which is much higher than that of the traditional FeOOH co-catalyst under the same conditions. More specifically, owing to the unique 3D interlinked nanochannel and confinement effect of Fe atom sites, the charge separation, hole transport at the interface, and interactions with H2O molecules have been effectively facilitated, which thus allows for enhancing PEC water oxidation properties.
Co-reporter:Xiaoqiang Du;Jingwei Huang
Dalton Transactions 2017 vol. 46(Issue 22) pp:7327-7331
Publication Date(Web):2017/06/06
DOI:10.1039/C7DT01230F
Developing noble metal-free water oxidation catalysts is essential for many energy conversion/storage processes (e.g., water splitting). Herein, we report a facile synthesis of CuO microspheres composed of ultrathin, single-crystal-like nanosheets via a simple solution method. The as-obtained CuO microspheres can serve as an active and stable water oxidation catalyst under electrochemical reaction conditions, owing to their unique structural features. In electrochemical water oxidation, this catalyst affords a current density of 10 mA cm−2 (a value related to practical relevance) at an overpotential of ∼0.48 V. Pure CuO was reported as a water oxidation catalyst (WOC) from near-neutral conditions to alkalescent conditions. Electrochemistry values agree with the Nernstian behavior, suggesting ne−/nH+ transfer prior to a chemical rate-determining step. Our results suggest that the delicate nanostructure can offer unique advantages for developing efficient water oxidation catalysts.
Co-reporter:Zheng Wan, Qian Xu, Hui Li, Yi Zhang, Yong Ding, Jide Wang
Applied Catalysis B: Environmental 2017 Volume 210(Volume 210) pp:
Publication Date(Web):5 August 2017
DOI:10.1016/j.apcatb.2017.03.056
•Four kinds of Co@CoO core-shell nanocrystals were prepared via a one-pot toluene-water two-phase interfacial reaction.•These as-obtained products were systematically investigated as visible light-driven water oxidation catalysts.•Co@CoO nanoplates were observed as excellent water oxidation catalysts (the maximum value of O2 yield is over 96%).•The high catalytic activity of the recovered Co@CoO nanoplates remained even after the sixth run.•A series of studies were conducted to investigate the catalysis stability issue of Co@CoO nanoplates.This paper introduces the first attempt of using well organized Co@CoO core-shell nanocrystals as an alternative toward noble metal catalysts for photocatalytic water splitting reactions. In this work, four kinds of stable magnetic Co@CoO core-shell nanocrystals were fabricated through a one-pot toluene-water two-phase interfacial reaction with oleic acid as a surfactant. The size and shape of the as-prepared crystals can be carefully adjusted through dynamically coating the closely packed monolayer of coordinating ligand onto the growing crystals. It is notable that spherical pine-nut-like hierarchical assemblies of Co@CoO core-shell nanoplates exhibit excellent photocatalytic activity (the maximum value of O2 yield is over 96%). Even after the sixth run, the high catalytic activity of the recovered Co@CoO core-shell nanoplates remained.Download high-res image (224KB)Download full-size image
Co-reporter:Yan Zhang, Xichen Zhou, Fuming Zhang, Tian Tian, Yong Ding, Hong Gao
Journal of Catalysis 2017 Volume 352(Volume 352) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.jcat.2017.05.020
•Hollow polyhedral nanocages Cu-ZIF-400, CuO/Co3O4 and Co3O4 catalysts are synthesized.•Three catalysts are obtained by modifying cobalt oxides with Cu using different methods.•All catalysts perform effective activities in electro/photocatalytic water oxidation.•Cu-ZIF-400 acts as the best electro/photocatalytic catalyst for oxygen evolution reaction.Cobalt oxides have been modified with Cu using different methods to obtain the catalysts of Cu-ZIF-400 (copper-doped cobalt oxide), CuO/Co3O4 and Co3O4 with identical morphology of hollow polyhedral nanocages. These catalysts were investigated simultaneously for electrocatalytic and photocatalytic water oxidation for the first time. Among them, Cu-ZIF-400 can act as the best electrochemical water oxidation catalyst with a low oxygen evolution reaction (OER) overpotential of 342 mV at 10.0 mA cm−2 in alkaline electrolyte. At the same time, a high turnover frequency (TOF) of 2.1 × 10−3 s−1 per metal atom was obtained over Cu-ZIF-400 at neutral conditions, which is comparable to those documented cobalt based catalysts. The different performances of catalysts can be attributed to the different doping methods. We hypothesize that the electrophilic Cu2+ makes the Co more electron-drawing and facilitates the nucleophilic addition of water, which enhanced OER activity of Cu-ZIF-400 catalyst.Download high-res image (89KB)Download full-size image
Co-reporter:Jingwei Huang, Xiaoqiang Du, YingYing Feng, Yukun Zhao and Yong Ding
Physical Chemistry Chemical Physics 2016 vol. 18(Issue 15) pp:9918-9921
Publication Date(Web):18 Mar 2016
DOI:10.1039/C6CP01543C
We have examined the catalytic activity of four different iron-based oxides doped with foreign elements using three common driving forces. The data clearly demonstrate that their water oxidation catalytic activity differ widely under different driving forces.
Co-reporter:Yingying Feng
The Journal of Physical Chemistry C 2016 Volume 120(Issue 1) pp:517-526
Publication Date(Web):December 16, 2015
DOI:10.1021/acs.jpcc.5b11533
Iron-based catalysts are of particular interest for water oxidation because of their high abundance, low toxicity, and rich redox properties. Herein, we report low cost porous iron-based oxides derived from calcining precursors of Prussian blue analogue (PBA) Mx[Fe(CN)6]y (M = Fe, Co, Ni). This synthesis approach involves a simple self-assembly technology and a low-temperature annealing procedure. These catalysts were investigated for photocatalytic, cerium(IV)-driven, and electrochemical water oxidation, and they exhibited superior activity. It is noteworthy that this photocatalytic water oxidation was conducted under neutral conditions that are similar to the natural photosystem II. The high initial turnover frequency (TOF) of ∼5.4 × 10–4 s–1 per transition metal atom at the first 60 s is obtained under neutral pH using porous CoxFe3–xO4 in photocatalytic water oxidation reaction, which is comparable with those published iron-based catalysts. Under cerium(IV)-driven water oxidation conditions, the TOF of porous CoxFe3–xO4 is 5.2 × 10–4 s–1 per transition metal atom, which is the highest value among all the documented iron oxides. In the electrochemical water oxidation, the porous NixFe3–xO4 catalyst exhibits a low overpotential of 402 mV at 10 mA cm–2. Meanwhile, the porous iron-based oxides possess beneficial ferromagnetic properties and excellent stability so that they were used repeatedly without loss in activity.
Co-reporter:Li Yu, Xiaoqiang Du, Yong Ding, Hongli Chen and Panpan Zhou
Chemical Communications 2015 vol. 51(Issue 98) pp:17443-17446
Publication Date(Web):07 Oct 2015
DOI:10.1039/C5CC07119D
[Cu5(OH)4(H2O)2(A-α-SiW9O33)2]10− (1) was tested as the first copper-containing polyoxometalate catalyst for O2 production via visible light-driven water oxidation. Multiple experiments confirm that 1 is an active and dominant catalyst during water oxidation.
Co-reporter:Yukun Zhao, Junqi Lin, Yongdong Liu, Baochun Ma, Yong Ding and Mindong Chen
Chemical Communications 2015 vol. 51(Issue 97) pp:17309-17312
Publication Date(Web):25 Sep 2015
DOI:10.1039/C5CC07448G
A mononuclear Co complex, [CoIII(DPK·OH)2]Cl (DPK = di(2-pyridyl)ketone), was synthesized and reported as a stable catalyst in visible light-driven water oxidation. The optimum turnover number (TON) of complex 1 is 1610, which, to the best of our knowledge, is the largest TON among metal–organic complexes for photocatalytic water oxidation.
Co-reporter:Xiaoqiang Du, Yong Ding, Fangyuan Song, Baochun Ma, Junwei Zhao and Jie Song
Chemical Communications 2015 vol. 51(Issue 73) pp:13925-13928
Publication Date(Web):21 Jul 2015
DOI:10.1039/C5CC04551G
An eleven iron-containing nanoscale inorganic polyanionic oxide cluster was reported as the first example for exceptional photocatalytic water oxidation. Under optimal conditions, a remarkable turn-over number (TON) of 1815 ± 50 and a turn-over frequency (TOFinitial) of 6.3 s−1 over 1 were achieved for water oxidation.
Co-reporter:Xiaoqiang Du, Yong Ding, Rui Xiang and Xu Xiang
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 16) pp:10648-10655
Publication Date(Web):18 Mar 2015
DOI:10.1039/C5CP00688K
CuFe2O4 nanocrystallines with cubic jacobsite structure have been obtained by heat treatment of the coprecipitation product, which were synthesized by the reaction of Cu2+ ions and Fe3+ ions under alkaline conditions. Reported here is the first copper-based catalyst for photocatalytic water oxidation using [Ru(bpy)3]Cl2 as the photosensitizer and Na2S2O8 as the sacrificial electron acceptor, respectively. An apparent TOF value of 1.2 μmol s−1 m−2 and an oxygen yield of 72.8% were obtained with CuFe2O4. The apparent TOF value with CuFe2O4 (1.2 μmol s−1 m−2) is the highest value among all heterogeneous photocatalytic water oxidation systems. CuFe2O4 can be easily separated from reaction solution by magnetic separation while maintaining excellent water oxidation activity in the fourth and fifth runs. The surface conditions of CuFe2O4 are slightly absent after examination by X-ray photoelectron spectroscopy (XPS) before and after the photocatalytic reaction.
Co-reporter:Yukun Zhao, Yan Zhang, Yong Ding and Mindong Chen
Dalton Transactions 2015 vol. 44(Issue 35) pp:15628-15635
Publication Date(Web):20 Jul 2015
DOI:10.1039/C5DT02046H
A unique hexagonal sheet-shaped NiO/CoO/Fe2O3 composite with irregularly shaped nanoparticles was fabricated for the first time through a simple co-precipitation and hydrothermal method. The NiO/CoO/Fe2O3 composite was characterized by numerous techniques (TEM, HRTEM, PXRD, EDX, ICP-AES, BET, and XPS) to confirm its structure and composition. This structure of the NiO/CoO/Fe2O3 composite may enhance the photocatalytic and electrocatalytic performance for water oxidation. Compared with NiO, CoO and Fe2O3, the NiO/CoO/Fe2O3 composite exhibits a lower overpotential and a much smaller Tafel slope of 49 mV dec−1 for water oxidation. At the same time, the composite possesses beneficial ferromagnetic properties and superior stability; thus, it can be used repeatedly without any loss in activity.
Co-reporter:Xiaoqiang Du, Jinli Zhao, Jiaqi Mi, Yong Ding, Panpan Zhou, Baochun Ma, Junwei Zhao, Jie Song
Nano Energy 2015 Volume 16() pp:247-255
Publication Date(Web):September 2015
DOI:10.1016/j.nanoen.2015.06.025
•Molecular semiconductor Na27[Fe11(H2O)14(OH)2(W3O10)2(α-SbW9O33)6] shows remarkable catalytic property for photocatalytic hydrogen evolution.•A H2 evolution rate of 820 μmol h−1 g−1 was achieved in the presence of catalyst without adding any photosensitizers and co-catalysts at neutral condition.•Six evidences proved that Fe11 is a true stable molecular catalyst during the photocatalytic hydrogen evolution.An unprecedented molecular polyanionic metal oxide cluster of eleven-FeIII substituted antimoniotungstate Na27[Fe11(H2O)14(OH)2(W3O10)2(α-SbW9O33)6]·103H2O(1) based on earth abundant elements has been successfully synthesized. A careful physical investigation of this molecule reveals that VB=−6.34 eV/CB=−4.39 eV, this unique physical properties ensures that 1 can be defined as a new type of nanoscale molecular semiconductor. This compound showed remarkable catalytic property for light driven H2 evolution activity. A H2 evolution rate of 820 μmol h−1 g−1 was achieved in the presence of 1 without adding any co-catalyst at neutral condition, which is a very high rate among all polyoxotungstate photocatalysts reported thus far. Six evidences proved that 1 is a true stable molecular catalyst during the photocatalytic hydrogen evolution.An unprecedented molecular polyanionic metal oxide cluster of eleven-FeIII substituted antimoniotungstate Na27[Fe11(H2O)14(OH)2(W3O10)2(α-SbW9O33)6]·103H2O showed remarkable catalytic property for light driven hydrogen evolution.
Co-reporter:Jie Wei;Yingying Feng;Panpan Zhou;Yan Liu;Jingyin Xu;Rui Xiang;Dr. Yong Ding;Chongchao Zhao;Linyuan Fan;Changwen Hu
ChemSusChem 2015 Volume 8( Issue 16) pp:2630-2634
Publication Date(Web):
DOI:10.1002/cssc.201500490
Abstract
To overcome the bottleneck of water splitting, the exploration of efficient, selective, and stable water oxidation catalysts (WOCs) is crucial. We report an all-inorganic, oxidatively and hydrolytically stable WOC based on a polyoxometalate [(A-α-SiW9O34)2Co8(OH)6(H2O)2(CO3)3]16− (Co8POM). As a cobalt(II)-based cubane water oxidation catalyst, Co8POM embeds double CoII4O3 cores. The self-assembled catalyst is similar to the oxygen evolving complex (OEC) of photosystem II (PS II). Using [Ru(bpy)3]2+ as a photosensitizer and persulfate as a sacrificial electron acceptor, Co8POM exhibits excellent water oxidation activity with a turnover number (TON) of 1436, currently the highest among bioinspired catalysts with a cubical core, and a high initial turnover frequency (TOF). Investigation by several spectroscopy, spectrometry, and other techniques confirm that Co8POM is a stable and efficient catalyst for visible light-driven water oxidation. The results offer a useful insight into the design of water oxidation catalysts.
Co-reporter:Xiaoqiang Du; Yong Ding;Chengqiang Li
ChemCatChem 2015 Volume 7( Issue 15) pp:2370-2376
Publication Date(Web):
DOI:10.1002/cctc.201500308
Abstract
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.
Co-reporter:Yukun Zhao, Yongdong Liu, Xiaoqiang Du, Ruixin Han and Yong Ding
Journal of Materials Chemistry A 2014 vol. 2(Issue 45) pp:19308-19314
Publication Date(Web):26 Sep 2014
DOI:10.1039/C4TA04360J
Co3V2O8, a uniform hexagonal sheet-shaped morphology, for the first time acted as a robust catalyst for water oxidation. Under optimal photocatalytic conditions (photoirradiation at λ ≥ 420 nm, Ru(bpy)3Cl2 as the photosensitizer, Na2S2O8 as the oxidant in borate buffer at pH = 8.5), the optimum apparent TOF of 10.9 μmol s−1 m−2 and O2 initial evolution rate of 31.7 μmol s−1 g−1 were achieved, which, to our best knowledge, are the highest values reported for heterogeneous photocatalytic water oxidation to date. Variables of the photocatalytic reaction, including catalyst concentrations, pH, dye concentrations and oxidant concentrations, were systemically studied. The oxygen atoms of the evolved oxygen came from water, as confirmed by isotope-labeled experiments. The stability of Co3V2O8 was tested and confirmed with multiple experiments (FT-IR, XRD, XPS), which indicated that Co3V2O8 is a stable catalyst under water oxidation. In addition, a mechanism of Co3V2O8 for the process of water oxidation was proposed.
Co-reporter:Shao Fu, Yongdong Liu, Yong Ding, Xiaoqiang Du, Fangyuan Song, Rui Xiang and Baochun Ma
Chemical Communications 2014 vol. 50(Issue 17) pp:2167-2169
Publication Date(Web):03 Jan 2014
DOI:10.1039/C3CC48059C
N,N′-Bis(salicylidene)ethylenediaminecobalt(II) (1) has been investigated as a highly efficient water oxidation precatalyst with a TON of 854 at pH = 9.0, using [Ru(bpy)3](ClO4)2 as a photosensitizer and Na2S2O8 as a sacrificial electron acceptor.
Co-reporter:Yongdong Liu, Rui Xiang, Xiaoqiang Du, Yong Ding and Baochun Ma
Chemical Communications 2014 vol. 50(Issue 84) pp:12779-12782
Publication Date(Web):02 Sep 2014
DOI:10.1039/C4CC04118F
A family of oxygen evolving catalysts was investigated, which was based on the most desired first-row transition metal iron. Among them, the highest turnover number of 2380 was obtained in acetate buffer at pH 4.5 with [(TPA)2Fe2(μ-O)(μ-OAc)]3+.
Co-reporter:Jie Wei, Yan Liu, Yong Ding, Chao Luo, Xiaoqiang Du and Junqi Lin
Chemical Communications 2014 vol. 50(Issue 80) pp:11938-11941
Publication Date(Web):14 Aug 2014
DOI:10.1039/C4CC04846F
δ-MnO2/o-MWCNTs were synthesized by coating MnO2 spontaneously on oxidized multi-walled carbon nanotubes via simple immersion of the o-MWCNTs into KMnO4 solution. This catalyst comprising the outer region of catalytic MnO2 and the inner region of highly conductive o-MWCNTs enhanced photocatalytic water oxidation activity.
Co-reporter:Jinli Zhao, Yong Ding, Jie Wei, Xiaoqiang Du, Yongze Yu, Ruixin Han
International Journal of Hydrogen Energy 2014 Volume 39(Issue 33) pp:18908-18918
Publication Date(Web):11 November 2014
DOI:10.1016/j.ijhydene.2014.09.084
•A molecular Keggin polyoxometalate containing cobalt was synthesized.•It catalyzed hydrogen evolution under visible light irradiation.•The hydrogen evolution average rate reaches 13395 μmol h−1 g−1.•Catalyst is stable in the photocatalytic process.A molecular Keggin polyoxometalate catalyst K7[CoIIICoII(H2O)W11O39](1) was successfully synthesized and efficiently catalyzed the hydrogen evolution. To the best of our knowledge, the molecular Keggin polyoxometalate catalyst 1 is the first reported polyoxometalate containing cobalt with efficient hydrogen production activity under the visible light irradiation. Under the optimal photocatalytic condition (photoirradiation at λ ≥ 420 nm, Eosin-Y as the photosensitizer, triethanolamine as the electron donor and Pt produced in situ photoreduction as co-catalyst), the turnover number (TON/based on catalyst) reached as high as 100; the initial quantum yield and the initial turnover frequency (TOF) at the first 10 min were 29% and 0.025 s−1, respectively. The hydrogen evolution average rate of 1 achieved 13,395 μmol h−1 g−1, as far as we are concerned, which is the highest among all the polyoxometalates photocatalytic systems reported so far. A possible mechanism of the hydrogen evolution reaction was proposed on the basis of steady-state fluorescence decay studies.
Co-reporter:Xiaoqiang Du;Jie Wei;Jinli Zhao;Ruixin Han; Yong Ding
Chemistry – An Asian Journal 2014 Volume 9( Issue 10) pp:2745-2750
Publication Date(Web):
DOI:10.1002/asia.201402652
Abstract
Flowerlike noble-metal-free γ-Fe2O3@NiO core–shell hierarchical nanostructures have been fabricated and examined as a catalyst in the photocatalytic oxidation of water with [Ru(bpy)3](ClO4)2 as a photosensitizer and Na2S2O8 as a sacrificial electron acceptor. An apparent TOF of 0.29 μmols−1 m−2 and oxygen yield of 51 % were obtained with γ-Fe2O3@NiO. The γ-Fe2O3@NiO core–shell hierarchical nanostructures could be easily separated from the reaction solution whilst maintaining excellent water-oxidation activity in the fourth and fifth runs. The surface conditions of γ-Fe2O3@NiO also remained unchanged after the photocatalytic reaction, as confirmed by X-ray photoelectron spectroscopy (XPS).
Co-reporter:Rui Xiang;Dr. Yong Ding;Dr. Junwei Zhao
Chemistry – An Asian Journal 2014 Volume 9( Issue 11) pp:3228-3237
Publication Date(Web):
DOI:10.1002/asia.201402483
Abstract
A mononuclear-cobalt(II)-substituted silicotungstate, K10[Co(H2O)2(γ-SiW10O35)2]⋅23 H2O (POM-1), has been evaluated as a light-driven water-oxidation catalyst. With in situ photogenerated [Ru(bpy)3]3+ (bpy=2,2′-bipyridine) as the oxidant, quite high catalytic turnover number (TON; 313), turnover frequency (TOF; 3.2 s−1), and quantum yield (ΦQY; 27 %) for oxygen evolution at pH 9.0 were acquired. Comparison experiments with its structural analogues, namely [Ni(H2O)2(γ-SiW10O35)2]10− (POM-2) and [Mn(H2O)2(γ-SiW10O35)2]10− (POM-3), gave the conclusion that the cobalt center in POM-1 is the active site. The hydrolytic stability of the title polyoxometalate (POM) was confirmed by extensive experiments, including UV/Vis spectroscopy, linear sweep voltammetry (LSV), and cathodic adsorption stripping analysis (CASA). As the [Ru(bpy)3]2+/visible light/sodium persulfate system was introduced, a POM–photosensitizer complex formed within minutes before visible-light irradiation. It was demonstrated that this complex functioned as the active species, which remained intact after the oxygen-evolution reaction. Multiple experimental parameters were investigated and the catalytic activity was also compared with the well-studied POM-based water-oxidation catalysts (i.e., [Co4(H2O)2(α-PW9O34)2]10− (Co4-POM) and [CoIIICoII(H2O)W11O39]7− (Co2-POM)) under optimum conditions.
Co-reporter:Wei Zhao, Chunxia Yang, Yong Ding and Baochun Ma
New Journal of Chemistry 2013 vol. 37(Issue 9) pp:2614-2618
Publication Date(Web):24 Jul 2013
DOI:10.1039/C3NJ00628J
Temperature-responsive characterization of solubility based on a surfactant-encapsulated polyoxometalate ([(C18H37)2(CH3)2N]8[HBW11O39]) in tert-butyl alcohol was described and used in catalytic oxidation of pyridines. The catalyst could be recovered and reused several times by controlling the temperature.
Co-reporter:Wei Zhao
Reaction Kinetics, Mechanisms and Catalysis 2013 Volume 109( Issue 2) pp:509-524
Publication Date(Web):2013 August
DOI:10.1007/s11144-013-0565-2
An excellent catalytic epoxidation system containing [π-C5H5N(CH2)15CH3]3[PW4O32]/H2O2/ethyl acetate/olefin has been prepared and shown to exhibit a unique reaction-controlled phase transfer behavior. The composition and structural changes of the catalyst [π-C5H5N(CH2)15CH3]3[PW4O32] (I) before, during and after reaction were investigated by 31P NMR, 31P MAS NMR, 183W NMR, IR, Raman and UV–Vis spectroscopy. The 31P MAS NMR and 31P NMR confirmed that the original catalyst was a mixture of heteropoly tungstophosphates. According to the 31P NMR and 183W NMR analysis, new phosphoperoxotungstate species, [PWxOy]z−, were produced in this catalytic system instead of the well known species of {PO4[WO(O2)2]4}3−. The active species of phosphoperoxotungstate containing many peroxo bonds should be similar to [(PO4){WO(O2)2}4]3−. The species degraded from H3PW12O40, H2O2 and quaternary ammonium were very complicated and the compositions were mainly dependent on the ratio of H2O2 to H3PW12O40.
Co-reporter:Baochun Ma, Zhenxin Zhang, Wenfeng Song, Xiaoling Xue, Yongze Yu, Zhensheng Zhao, Yong Ding
Journal of Molecular Catalysis A: Chemical 2013 Volumes 368–369() pp:152-158
Publication Date(Web):March 2013
DOI:10.1016/j.molcata.2012.11.022
A novel homogeneous vanadium-substituted polyoxometalate catalyst of [n-Bu4N]3H3[PW9V3O40] showed good catalytic activity for the activation of CH bonds of toluene and substituted toluene with TBHP (70% aq) under solvent-free conditions. Under the optimal conditions, a 65% yield of benzaldehyde and a TON of 5221 were obtained over this catalyst at 343 K. This catalyst also showed good conversion and selectivity for the oxidation of a series of substituted toluene. The vanadium-substituted Keggin-POM was not decomposed to some species upon the treatment of 530-fold of TBHP by IR characterization. A free radical mechanism was proposed based on the experimental results and the literature supports.Graphical abstractHighlights► A homogeneous vanadium-substituted polyoxometalate catalyst was prepared. ► This catalyst showed good activity for oxidation of toluene and substituted toluene. ► A free radical mechanism was proposed based on the experimental results.
Co-reporter:Yong Ding, Wei Zhao, Wenfeng Song, Zhenxin Zhang and Baochun Ma
Green Chemistry 2011 vol. 13(Issue 6) pp:1486-1489
Publication Date(Web):13 Apr 2011
DOI:10.1039/C1GC15213K
A vanadium-substituted polyoxometalate, K6[PW9V3O40]·4H2O, was used as a recyclable and effective catalyst for the oxidation of pyridines. The reactions were successfully conducted in water under mild conditions. The catalyst could be easily recovered and reused.
Co-reporter:Yong Ding, Wei Zhao
Journal of Molecular Catalysis A: Chemical 2011 Volume 337(1–2) pp:45-51
Publication Date(Web):1 March 2011
DOI:10.1016/j.molcata.2011.01.012
A novel temperature-controlled phase transfer catalyst of [(C18H37)2(CH3)2N]7[PW11O39] has been developed for the oxidation of pyridines and alcohols with hydrogen peroxide. The reactions were conducted in 1,4-dioxane, and high yields of the corresponding heterocyclic N-oxides and ketones were obtained under relative mild conditions. The catalyst could be easily recovered and reused after reaction with cooling. There was no discernable loss in activity and selectivity after several reaction cycles.Graphical abstractResearch highlights► A novel temperature-controlled phase transfer catalyst was prepared. ► This catalyst showed good activity in the oxidation of pyridines and alcohols. ► The catalyst could be easily recovered and reused after reaction.
Co-reporter:Yong Ding;Wei Zhao;Yingshuai Zhang
Reaction Kinetics, Mechanisms and Catalysis 2011 Volume 102( Issue 1) pp:85-92
Publication Date(Web):2011 February
DOI:10.1007/s11144-010-0241-8
A facile and reusable catalytic system for alcohol oxidation with hydrogen peroxide was designed based on a temperature-responsive catalyst. Several kinds of alcohols were efficiently oxidized in high yields under relatively mild conditions. The catalyst could be easily recovered and reused.
Co-reporter:Wei Zhao;Zhenxin Zhang
Reaction Kinetics, Mechanisms and Catalysis 2011 Volume 102( Issue 1) pp:93-102
Publication Date(Web):2011 February
DOI:10.1007/s11144-010-0242-7
A novel temperature-controlled phase transfer catalytic system based on [(C18H37)2(CH3)2N]7[PW11O39] for olefin epoxidation was demonstrated. The reaction was conducted in a non-chlorinated solvent of ethyl acetate with hydrogen peroxide. The catalyst was easily recovered and reused even ten cycles without loss in activity and selectivity.
Co-reporter:Wei Zhao;Baochun Ma;Wenyuan Qiu
Reaction Kinetics, Mechanisms and Catalysis 2011 Volume 102( Issue 2) pp:459-472
Publication Date(Web):2011 April
DOI:10.1007/s11144-010-0269-9
Mesoporous silica KIT-1 supported with active polytungstophosphate anion of PWxOy species was synthesized and successfully used to catalyze the alkene epoxidation in the environmentally benign solvent of ethyl acetate. The immobilized catalyst of KIT-N+-PWxOy was stable and robust for the epoxidation. In addition, the active species of PWxOy, the molecular sieve support of KIT-1 and the immobilized catalyst of KIT-N+-PWxOy were characterized by FT-IR, UV–vis, XRD, 31P MAS NMR, SEM, N2 adsorption/desorption, ICP and XPS in detail.
Co-reporter:Yong Ding, Wei Zhao, Hui Hua and Baochun Ma
Green Chemistry 2008 vol. 10(Issue 9) pp:910-913
Publication Date(Web):16 Jul 2008
DOI:10.1039/B808404A
The epoxidation of alkenes was successfully catalyzed by a recyclable and environmentally benign catalytic system: [π-C5H5N(CH2)15CH3]3[PW4O32]/H2O2/ethyl acetate/olefin
Co-reporter:Xiaoling Xue, Wei Zhao, Baochun Ma, Yong Ding
Catalysis Communications (5 December 2012) Volume 29() pp:73-76
Publication Date(Web):5 December 2012
DOI:10.1016/j.catcom.2012.09.021
A temperature-responsive phase transfer catalyst [(C18H37)2(CH3)2N]7PW11O39, could act as an efficient catalyst for selective oxidation of sulfides with 30% aqueous H2O2. Various kinds of sulfides were successfully oxidized to their corresponding sulfones with over 96% yields in a relatively short time and mild conditions. During reaction at 333 K, the catalyst dissolved completely and the oxidation was conducted homogeneously. Before and after reaction, the catalyst was insoluble with cooling, so it is easily recovered and reused. The catalyst was characterized by elemental analysis, FT-IR and 31P NMR.Graphical abstractA temperature-responsive phase transfer catalyst [(C18H37)2(CH3)2N]7PW11O39 was developed and showed good activity for oxidation of sulfides to their corresponding sulfones. The catalyst acts as homogeneous during oxidation reaction at 333 K, while at room temperature it's not soluble and easily recycled.Download full-size imageHighlights► A polyoxometalate-based temperature-responsive phase transfer catalyst was prepared. ► It efficiently catalyzed oxidation of various sulfides with H2O2 and was recyclable. ► High yields of sulfones (over 96%) were obtained in a short time and mild conditions. ► This system has both the advantage of homogeneous and heterogeneous catalysis.
Co-reporter:Baochun Ma, Yingshuai Zhang, Yong Ding, Wei Zhao
Catalysis Communications (30 April 2010) Volume 11(Issue 9) pp:853-857
Publication Date(Web):30 April 2010
DOI:10.1016/j.catcom.2010.02.022
A dilacunary silicotungstate, K8[γ-SiW10O36]·13H2O, catalyzed the selective oxidation of alcohols with 30% aqueous hydrogen peroxide. The reaction was carried out in an aqueous/oil biphasic system, which allowed easy recovery of a catalyst under relative mild conditions. The high yields of ketones were obtained in oxidation of alcohols by the dilacunary silicotungstate and the catalyst was recycled five times without activity loss at room temperature.A dilacunary silicotungstate, K8[γ-SiW10O36]·13H2O, catalyzed the selective oxidation of alcohols with 30% aqueous hydrogen peroxide. The reaction was carried out in an aqueous/oil biphasic system, which allowed easy recovery of a catalyst under relative mild conditions.Download full-size image
Co-reporter:Wei Zhao, Yingshuai Zhang, Baochun Ma, Yong Ding, Wenyuan Qiu
Catalysis Communications (20 February 2010) Volume 11(Issue 6) pp:527-531
Publication Date(Web):20 February 2010
DOI:10.1016/j.catcom.2009.12.010
Different kinds of alcohols were efficiently transformed into corresponding ketones catalyzed by a Lacunary Keggin polyoxometalate of K8[BW11O39H]·13H2O in water with hydrogen peroxide. The system not only catalyzes the oxidation of alcohols but also avoids the use of organic solvent. The reactions were carried out in an aqueous/oil system. The catalyst was reused for the next cycle from the organic product by separation of the aqueous phase. High yields of ketones were obtained in oxidation of secondary alcohols. Benzyl alcohol was converted to benzaldehyde in high conversion and selectivity.
Co-reporter:Zhenxin Zhang, Wei Zhao, Baochun Ma, Yong Ding
Catalysis Communications (15 December 2010) Volume 12(Issue 4) pp:318-322
Publication Date(Web):15 December 2010
DOI:10.1016/j.catcom.2010.09.026
Inorganic–organic hybrid material was formed by [PW11O39]7− and benzene-1,3,5-[tris(phenyl-4-carboxylic acid)] tris (2-trimethyl-ammonium ethyl) ester. This hybrid material behaved as a very effective and selective heterogeneous catalyst for the epoxidation of olefins with hydrogen peroxide as an oxidant. This heterogeneous catalyst could be easily recovered and reused after reaction without loss of activity.A heterogeneous catalytic material for epoxidation has been synthesized by preparing insoluble inorganic–organic hybrid compounds based on a tripodal organic triammonium cation and a catalytically active POM [PW11O39]7−.Download full-size imageResearch Highlights► A heterogeneous catalytic material based on [PW11O39]7-, BTE-PW11O39, has been synthesized. ► BTE-PW11O39 catalyzes olefins epoxidation efficiently. ► BTE-PW11O39 can be reused without loss of activity.
Co-reporter:Xiaoqiang Du, Jingwei Huang and Yong Ding
Dalton Transactions 2017 - vol. 46(Issue 22) pp:NaN7331-7331
Publication Date(Web):2017/05/12
DOI:10.1039/C7DT01230F
Developing noble metal-free water oxidation catalysts is essential for many energy conversion/storage processes (e.g., water splitting). Herein, we report a facile synthesis of CuO microspheres composed of ultrathin, single-crystal-like nanosheets via a simple solution method. The as-obtained CuO microspheres can serve as an active and stable water oxidation catalyst under electrochemical reaction conditions, owing to their unique structural features. In electrochemical water oxidation, this catalyst affords a current density of 10 mA cm−2 (a value related to practical relevance) at an overpotential of ∼0.48 V. Pure CuO was reported as a water oxidation catalyst (WOC) from near-neutral conditions to alkalescent conditions. Electrochemistry values agree with the Nernstian behavior, suggesting ne−/nH+ transfer prior to a chemical rate-determining step. Our results suggest that the delicate nanostructure can offer unique advantages for developing efficient water oxidation catalysts.
Co-reporter:Yukun Zhao, Yan Zhang, Yong Ding and Mindong Chen
Dalton Transactions 2015 - vol. 44(Issue 35) pp:NaN15635-15635
Publication Date(Web):2015/07/20
DOI:10.1039/C5DT02046H
A unique hexagonal sheet-shaped NiO/CoO/Fe2O3 composite with irregularly shaped nanoparticles was fabricated for the first time through a simple co-precipitation and hydrothermal method. The NiO/CoO/Fe2O3 composite was characterized by numerous techniques (TEM, HRTEM, PXRD, EDX, ICP-AES, BET, and XPS) to confirm its structure and composition. This structure of the NiO/CoO/Fe2O3 composite may enhance the photocatalytic and electrocatalytic performance for water oxidation. Compared with NiO, CoO and Fe2O3, the NiO/CoO/Fe2O3 composite exhibits a lower overpotential and a much smaller Tafel slope of 49 mV dec−1 for water oxidation. At the same time, the composite possesses beneficial ferromagnetic properties and superior stability; thus, it can be used repeatedly without any loss in activity.
Co-reporter:Jingwei Huang, Xiaoqiang Du, YingYing Feng, Yukun Zhao and Yong Ding
Physical Chemistry Chemical Physics 2016 - vol. 18(Issue 15) pp:NaN9921-9921
Publication Date(Web):2016/03/18
DOI:10.1039/C6CP01543C
We have examined the catalytic activity of four different iron-based oxides doped with foreign elements using three common driving forces. The data clearly demonstrate that their water oxidation catalytic activity differ widely under different driving forces.
Co-reporter:Yongdong Liu, Rui Xiang, Xiaoqiang Du, Yong Ding and Baochun Ma
Chemical Communications 2014 - vol. 50(Issue 84) pp:NaN12782-12782
Publication Date(Web):2014/09/02
DOI:10.1039/C4CC04118F
A family of oxygen evolving catalysts was investigated, which was based on the most desired first-row transition metal iron. Among them, the highest turnover number of 2380 was obtained in acetate buffer at pH 4.5 with [(TPA)2Fe2(μ-O)(μ-OAc)]3+.
Co-reporter:Xiaoqiang Du, Yong Ding, Fangyuan Song, Baochun Ma, Junwei Zhao and Jie Song
Chemical Communications 2015 - vol. 51(Issue 73) pp:NaN13928-13928
Publication Date(Web):2015/07/21
DOI:10.1039/C5CC04551G
An eleven iron-containing nanoscale inorganic polyanionic oxide cluster was reported as the first example for exceptional photocatalytic water oxidation. Under optimal conditions, a remarkable turn-over number (TON) of 1815 ± 50 and a turn-over frequency (TOFinitial) of 6.3 s−1 over 1 were achieved for water oxidation.
Co-reporter:Yukun Zhao, Junqi Lin, Yongdong Liu, Baochun Ma, Yong Ding and Mindong Chen
Chemical Communications 2015 - vol. 51(Issue 97) pp:NaN17312-17312
Publication Date(Web):2015/09/25
DOI:10.1039/C5CC07448G
A mononuclear Co complex, [CoIII(DPK·OH)2]Cl (DPK = di(2-pyridyl)ketone), was synthesized and reported as a stable catalyst in visible light-driven water oxidation. The optimum turnover number (TON) of complex 1 is 1610, which, to the best of our knowledge, is the largest TON among metal–organic complexes for photocatalytic water oxidation.
Co-reporter:Li Yu, Yong Ding, Min Zheng, Hongli Chen and Junwei Zhao
Chemical Communications 2016 - vol. 52(Issue 100) pp:NaN14497-14497
Publication Date(Web):2016/04/18
DOI:10.1039/C6CC02728H
[{β-SiNi2W10O36(OH)2(H2O)}4]24− (1) was reported as efficient, robust visible light-driven water oxidation catalyst for the first time. Of the reported polyoxometalates containing nickel, 1 shows the best photocatalytic O2 evolution activity with a TON of 335 and TOF of 1.7 s−1.
Co-reporter:Li Yu, Yong Ding, Min Zheng, Hongli Chen and Junwei Zhao
Chemical Communications 2016 - vol. 52(Issue 100) pp:NaN14499-14499
Publication Date(Web):2016/12/09
DOI:10.1039/C6CC90561G
Correction for ‘[{β-SiNi2W10O36(OH)2(H2O)}4]24−: a new robust visible light-driven water oxidation catalyst based on nickel-containing polyoxometalate’ by Li Yu et al., Chem. Commun., 2016, DOI: 10.1039/c6cc02728h.
Co-reporter:Xiaoqiang Du, Yong Ding, Rui Xiang and Xu Xiang
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 16) pp:NaN10655-10655
Publication Date(Web):2015/03/18
DOI:10.1039/C5CP00688K
CuFe2O4 nanocrystallines with cubic jacobsite structure have been obtained by heat treatment of the coprecipitation product, which were synthesized by the reaction of Cu2+ ions and Fe3+ ions under alkaline conditions. Reported here is the first copper-based catalyst for photocatalytic water oxidation using [Ru(bpy)3]Cl2 as the photosensitizer and Na2S2O8 as the sacrificial electron acceptor, respectively. An apparent TOF value of 1.2 μmol s−1 m−2 and an oxygen yield of 72.8% were obtained with CuFe2O4. The apparent TOF value with CuFe2O4 (1.2 μmol s−1 m−2) is the highest value among all heterogeneous photocatalytic water oxidation systems. CuFe2O4 can be easily separated from reaction solution by magnetic separation while maintaining excellent water oxidation activity in the fourth and fifth runs. The surface conditions of CuFe2O4 are slightly absent after examination by X-ray photoelectron spectroscopy (XPS) before and after the photocatalytic reaction.
Co-reporter:Shao Fu, Yongdong Liu, Yong Ding, Xiaoqiang Du, Fangyuan Song, Rui Xiang and Baochun Ma
Chemical Communications 2014 - vol. 50(Issue 17) pp:NaN2169-2169
Publication Date(Web):2014/01/03
DOI:10.1039/C3CC48059C
N,N′-Bis(salicylidene)ethylenediaminecobalt(II) (1) has been investigated as a highly efficient water oxidation precatalyst with a TON of 854 at pH = 9.0, using [Ru(bpy)3](ClO4)2 as a photosensitizer and Na2S2O8 as a sacrificial electron acceptor.
Co-reporter:Jie Wei, Yan Liu, Yong Ding, Chao Luo, Xiaoqiang Du and Junqi Lin
Chemical Communications 2014 - vol. 50(Issue 80) pp:NaN11941-11941
Publication Date(Web):2014/08/14
DOI:10.1039/C4CC04846F
δ-MnO2/o-MWCNTs were synthesized by coating MnO2 spontaneously on oxidized multi-walled carbon nanotubes via simple immersion of the o-MWCNTs into KMnO4 solution. This catalyst comprising the outer region of catalytic MnO2 and the inner region of highly conductive o-MWCNTs enhanced photocatalytic water oxidation activity.
Co-reporter:Yukun Zhao, Yongdong Liu, Xiaoqiang Du, Ruixin Han and Yong Ding
Journal of Materials Chemistry A 2014 - vol. 2(Issue 45) pp:NaN19314-19314
Publication Date(Web):2014/09/26
DOI:10.1039/C4TA04360J
Co3V2O8, a uniform hexagonal sheet-shaped morphology, for the first time acted as a robust catalyst for water oxidation. Under optimal photocatalytic conditions (photoirradiation at λ ≥ 420 nm, Ru(bpy)3Cl2 as the photosensitizer, Na2S2O8 as the oxidant in borate buffer at pH = 8.5), the optimum apparent TOF of 10.9 μmol s−1 m−2 and O2 initial evolution rate of 31.7 μmol s−1 g−1 were achieved, which, to our best knowledge, are the highest values reported for heterogeneous photocatalytic water oxidation to date. Variables of the photocatalytic reaction, including catalyst concentrations, pH, dye concentrations and oxidant concentrations, were systemically studied. The oxygen atoms of the evolved oxygen came from water, as confirmed by isotope-labeled experiments. The stability of Co3V2O8 was tested and confirmed with multiple experiments (FT-IR, XRD, XPS), which indicated that Co3V2O8 is a stable catalyst under water oxidation. In addition, a mechanism of Co3V2O8 for the process of water oxidation was proposed.
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