Prolonged Electron Lifetime in Ordered TiO<sub>2</sub> Mesophyll Cell‐Like Microspheres for Efficient Photocatalytic Water Reduction and Oxidation

Zhang, Yanyan; Wu, Bo; Tang, Yuxin; Qi, Dianpeng; Wang, Ning; Wang, Xiaotian; Ma, Xueling; Sum, Tze Chien; Chen, Xiao

doi:10.1002/smll.201503611

Cited by 50 publications

(22 citation statements)

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“…This indicates that the water-splitting reaction over the samples is associated with the DRS absorption spectra [44]. Compared with other typical TiO2/SrTiO3 nanostructures with different morphologies [26,[30][31][32][33][34], the H-TiO2/SrTiO3 heterostructured porous microspheres present much higher photocatalytic activity. This can be attributed to the synergistic effect of the unique porous sphere structure, heterostructure, and appropriate oxygen-vacancy and Ti 3+ contents, which serve as trapping sites, preventing the rapid recombination of charge carriers and improving the interfacial electron-transfer rate and the migration efficiency of photoinduced electrons.…”

Section: Resultsmentioning

confidence: 90%

“…Compared with their bulk counterparts of the same size, porous nanoparticles exhibit superior performance owing to their high surface area, multiple channels, and lower resistance to mass transfer in catalytic systems, all of which endow them with multifunctional capabilities [30,31]. Until now, there have been no reports on the synthesis of TiO2/SrTiO3 porous microspheres.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

et al. 2016

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The production of H2 and O2 from solar-light photocatalytic water splitting has attracted significant research attention as a clean and renewable source of energy. In this study, hydrogenated TiO2/SrTiO3 porous microspheres were prepared as a high-performance photocatalyst. Titanium glycerolate and then strontium complex precursors were first prepared via a two-step solvothermal process, then, after calcination in air and subsequent H2/Ar reduction treatments, hydrogenated TiO2/SrTiO3 porous microspheres with controllable defects and band positions were prepared. Several characterization techniques were used to demonstrate that the catalyst heterostructures, the oxygen-vacancy content, and the unique porous structures synergistically enhanced the visible-light harvesting abilities and photogenerated charge separation, and resulted in improved photocatalytic efficiency for H2 and O2 evolution. As expected, the optimum treatment conditions provided hydrogenated TiO2/SrTiO3 porous microspheres that showed excellent photocatalytic activity with H2 and O2 evolution rates of 239.97 and 103.79 μmol h −1 (50 mg catalyst, under AM 1.5 irradiation), respectively, which were ca. 5.9 and 6.6 times higher, respectively, than those of solid TiO2/SrTiO3 materials. Thus, this type of hydrogenated TiO2/SrTiO3 porous microsphere catalyst shows great potential as a photocatalyst for solar-energy conversion applications.

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Section: Resultsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

et al. 2016

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“…In this regard, increasing the electrocatalytic active sites on the surface of graphene seems more promising in developing highly effective graphene‐based composite photocatalysts. In addition, increasing the adsorption and diffusion kinetics is beneficial for the enrichment of reactants on the active sites and further activation, which could be achieved through suitable surface modification, constructing the 3D porous or hierarchical nanostructures . In addition, the photostability of semiconductors should be also enhanced to meet the requirements of the practical applications.…”

Section: Design Rules Of Graphene‐based Composite Photocatalystsmentioning

confidence: 99%

Graphene in Photocatalysis: A Review

Wageh

et al. 2016

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In recent years, heterogeneous photocatalysis has received much research interest because of its powerful potential applications in tackling many important energy and environmental challenges at a global level in an economically sustainable manner. Due to their unique optical, electrical, and physicochemical properties, various 2D graphene nanosheets-supported semiconductor composite photocatalysts have been widely constructed and applied in different photocatalytic fields. In this review, fundamental mechanisms of heterogeneous photocatalysis, including thermodynamic and kinetics requirements, are first systematically summarized. Then, the photocatalysis-related properties of graphene and its derivatives, and design rules and synthesis methods of graphene-based composites are highlighted. Importantly, different design strategies, including doping and sensitization of semiconductors by graphene, improving electrical conductivity of graphene, increasing eloectrocatalytic active sites on graphene, strengthening interface coupling between semiconductors and graphene, fabricating micro/nano architectures, constructing multi-junction nanocomposites, enhancing photostability of semiconductors, and utilizing the synergistic effect of various modification strategies, are thoroughly summarized. The important applications including photocatalytic pollutant degradation, H production, and CO reduction are also addressed. Through reviewing the significant advances on this topic, it may provide new opportunities for designing highly efficient 2D graphene-based photocatalysts for various applications in photocatalysis and other fields, such as solar cells, thermal catalysis, separation, and purification.

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“…[20] Moreover,highly exposed active sites with monocrystalline character contribute to favorable electron transfer,thus facilitating the OER process. [21] Moreover,C ZH-3 has ah igher cobalt ratio than that of CZH-1 and CZH-2, suggesting an increased number of active sites provided by a-Co(OH) 2 that are able to benefit electrocatalytic OER. CZH-1 presents discontinuous conductive networks,i nw hich adjacent discrete spatial clustering of nanosheets is observed.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…Conversely,t he continuously interlocked nanosheets (CZH-3) construct extended conductive networks,f orming efficient electron transport pathways to accelerate OER kinetics. [21] Moreover,C ZH-3 has ah igher cobalt ratio than that of CZH-1 and CZH-2, suggesting an increased number of active sites provided by a-Co(OH) 2 that are able to benefit electrocatalytic OER. Thet hicker nanosheets in CZH-4 reduce the specific surface area of catalytic sites (despite the fact that it possesses the highest cobalt ratios and interconnected networks) leading to decreased OER performance in contrast to CZH-3.…”

Section: Angewandte Chemiementioning

confidence: 99%

Topotactic Consolidation of Monocrystalline CoZn Hydroxides for Advanced Oxygen Evolution Electrodes

et al. 2016

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We present ar oom temperature topotactic consolidation of cobalt and zinc constituents into monocrystalline CoZn hydroxide nanosheets,b yalocalized corrosion of zinc foils with cobalt precursors.B yv irtue of similar lattice orientation and structure coordination, the hybrid hydroxides amalgamate atomically without phase separation. Importantly,t his in situ growth strategy,i nc ombination with configurable percolated nanosheets,r enders ah igh areal density of catalytic sites,i mmobilized structures,a nd conductive pathways between the nanosheets and underlying foils-all of whicha llow monocrystalline CoZn hydroxiden anosheet materials to function as effective electrodes for electrochemical oxygen evolution reactions.T his convenient and eco-friendly topotactical transformation approach facilitates high-quality single crystal growth with improved multiphase purity and homogeneity,whichcan be extended to other transition metals for the fabrication of advanced functional nanocomposites.Topotactic transformation defines structural alteration within the crystal lattice (such as displacement or exchange of atoms) of amaterial, where the formed lattices inherit one or more crystallographic orientations from the initial precursor. [1] Thep rowess of topotactical conversion is that it supersedes equilibrium crystal shapes/habits,t hereby allowing phase to be correlated with coordinated structures at atomic homogeneity. [2] Nonetheless,o btaining high-quality monocrystalline topochemical reactions is still ac hallenge and often demands high-temperature processes [3] or expensive equipment, such as ultrahigh vacuum pulsed laser, [4] thereby making the technique impractical for largescale applications.F urthermore,r eported topotactic transformations,s uch as metal oxidization, [5] phase transition, [6] and conversion of hydroxides into oxides or metals, [7] primarily involve as ingle metal cation, which precludes formation of bi-/multinary constituents.Inthe context of the ability of multi-component materials to alter electronic states that exhibit strong interplay between the strength of surface intermediate bonds and electrochemical reactivity, [8] it is essential to readily access topotactic consolidation of two or more constituents within ah omogeneous entity.Herein, we demonstrate am ild room temperature topotactic consolidation of cobalt-zinc hydroxides (CZH) with an ensemble of nanosheets,byaninsitu corrosion of zinc foils mediated by cobalt precursors.T he defining advantage of such am etal corrosion technique is its undeniably simple low-cost route,w hich enables spontaneous electrochemical dissolution-redeposition without the expense of external energy.T he chemical etching dissolves metals into their ion derivatives,w hich further self-assemble into their respective oxides or inorganic salts. [9] Though less appreciated, the conversion of metallic substrates into their constituent materials involves at opotactic reconstruction of crystal lattices,a sp er the crystal habit of the employed precursor. By virtue of...

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Prolonged Electron Lifetime in Ordered TiO₂ Mesophyll Cell‐Like Microspheres for Efficient Photocatalytic Water Reduction and Oxidation

Cited by 50 publications

References 82 publications

Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

Graphene in Photocatalysis: A Review

Topotactic Consolidation of Monocrystalline CoZn Hydroxides for Advanced Oxygen Evolution Electrodes

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Prolonged Electron Lifetime in Ordered TiO2 Mesophyll Cell‐Like Microspheres for Efficient Photocatalytic Water Reduction and Oxidation

Cited by 50 publications

References 82 publications

Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

Graphene in Photocatalysis: A Review

Topotactic Consolidation of Monocrystalline CoZn Hydroxides for Advanced Oxygen Evolution Electrodes

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Product

Resources

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Prolonged Electron Lifetime in Ordered TiO₂ Mesophyll Cell‐Like Microspheres for Efficient Photocatalytic Water Reduction and Oxidation