Microwave‐Assisted Synthesis of Ultrastable Cu@TiO<sub>2</sub> Core‐Shell Nanowires with Tunable Diameters via a Redox‐Hydrolysis Synergetic Process

Liu, Deyu; Wu, Binghui; Mubeen, Syed; Ding, Keqiang; Zeng, Hongmei; Chuong, Tracy T; Moskovits, Martin; Stucky, Galen D.

doi:10.1002/cnma.201800210

Cited by 10 publications

(12 citation statements)

References 39 publications

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“…Previous work on Cu@TiO 2 core–shell motifs has focused on applications, such as but not limited to H 2 conversion, the photocatalytic degradation of methyl orange, , and dye-sensitized solar cells . With respect to CO 2 reduction, it is important to note that essentially all of the prior studies relate to either photocatalysis or electrocatalysis, which possess a different scope from what we intend to investigate herein.…”

Section: Introductionmentioning

confidence: 99%

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO₂ Hydrogenation

Salvatore

Deng

Yue

et al. 2020

ACS Appl. Mater. Interfaces

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The rational synthesis of Cu@TiO2 core@shell nanowire (NW) structures was thoroughly explored using a microwave-assisted method through the tuning of experimental parameters such as but not limited to (i) controlled variation in molar ratios, (ii) the effect of discrete Ti precursors, (iii) the method of addition of the precursors themselves, and (iv) time of irradiation. Uniform coatings were obtained using Cu/Ti molar ratios of 1:2, 1:1, 2:1, and 4:1, respectively. It should be noted that although relative molar precursor concentrations primarily determined the magnitude of the resulting shell size, the dependence was nonlinear. Moreover, additionally important reaction parameters, such as precursor identity, the means of addition of precursors, and the reaction time, were individually explored with the objective of creating a series of optimized reaction conditions. As compared with Cu NWs alone, it is evident that both of the Cu@TiO2 core–shell NW samples, regardless of pretreatment conditions, evinced much better catalytic performance, up to as much as 20 times greater activity as compared with standard Cu NWs. These results imply the significance of the Cu/TiO2 interface in terms of promoting CO2 hydrogenation, because TiO2 alone is known to be inert for this reaction. Furthermore, it is additionally notable that the N2 annealing pretreatment is crucial in terms of preserving the overall Cu@TiO2 core@shell structure. We also systematically analyzed and tracked the structural and chemical evolution of our catalysts before and after the CO2 reduction experiments. Indeed, we discovered that the core@shell wire motif was essentially maintained and conserved after this high-temperature reaction process, thereby accentuating the thermal stability and physical robustness of our as-prepared hierarchical motifs.

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Section: Introductionmentioning

confidence: 99%

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO₂ Hydrogenation

Salvatore

Deng

Yue

et al. 2020

ACS Appl. Mater. Interfaces

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“…This core−shell motif not only maximized the use of an inexpensive, abundant, but still catalytically active Cu core but also enabled the ability to customize the size of the TiO 2 shell so as to optimize catalytic reactivity. Whereas prior microwave methods 39 had used inherently hazardous Ti precursors, in terms of novelty, our approach was different and distinctive for several crucial reasons. First, we modified the microwave-based synthesis protocol to incorporate a safer precursor molecule, i.e., titanium butoxide, TBOT, within the context of an aqueous, surfactant-free methodology, so as to maximize catalytic performance by minimizing the presence of any residual impurities.…”

Section: Microwave-assisted Chemistrymentioning

confidence: 99%

Exploring Strategies toward Synthetic Precision Control within Core–Shell Nanowires

Salvatore

Wong

2021

Acc. Chem. Res.

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Metrics & MoreArticle Recommendations CONSPECTUS: Achieving precision and reproducibility in terms of physical structure and chemical composition within arbitrary nanoscale systems remains a "holy grail" challenge for nanochemistry. Because nanomaterials possess fundamentally distinctive size-dependent electronic, optical, and magnetic properties with wide-ranging applicability, the ability to produce homogeneous and monodisperse nanostructures with precise size and shape control, while maintaining a high degree of sample quality, purity, and crystallinity, remains a key synthetic objective. Moreover, it is anticipated that the methodologies developed to address this challenge ought to be reasonably simple, scalable, mild, nontoxic, high-yield, and cost-effective, while minimizing reagent use, reaction steps, byproduct generation, and energy consumption. The focus of this Account revolves around the study of various types of nanoscale onedimensional core−shell motifs, prepared by our group. These offer a compact structural design, characterized by atom economy, to bring together two chemically distinctive (and potentially sharply contrasting) material systems into contact within the structural context of an extended, anisotropic configuration. Herein, we describe complementary strategies aimed at resolving the aforementioned concerns about precise structure and compositional control through the infusion of careful "quantification" and systematicity into customized, reasonably sustainable nanoscale synthetic protocols, developed by our group. Our multipronged approach involved the application of (a) electrodeposition, (b) electrospinning, (c) a combination of underpotential deposition and galvanic displacement reactions, and (d) microwave-assisted chemistry to diverse core−shell model systems, such as (i) carbon nanotube−SiO 2 composites, (ii) SnO 2 /TiO 2 motifs, (iii) ultrathin Pt-monolayer shell-coated alloyed metal core nanowires, and (iv) Cu@TiO 2 nanowires, for applications spanning optoelectronics, photocatalysis, electrocatalysis, and thermal CO 2 hydrogenation, respectively. In so doing, over the years, we have reported on a number of different characterization tools involving spectroscopy (e.g., extended X-ray absorption fine structure (EXAFS) spectroscopy) and microscopy (e.g., high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM)) for gaining valuable insights into the qualitative and quantitative nature of not only the inner core and outer shell themselves but also their intervening interface. While probing the functional catalytic behavior of a few of these core−shell structures under realistic operando conditions, using dynamic, in situ characterization techniques, we found that local and subtle changes in chemical composition and physical structure often occur during the reaction process itself. As such, nuanced differences in atomic packing, facet exposure, degree of derivatization, defect content, and/or extent of crystallinity can impact upon observed propert...

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“…Among numerous photocatalysts, TiO 2 is still one of the best candidates due to its favorable stability, high activity, nontoxicity and low price [7–11] . Nevertheless, electron‐hole pairs recombine too fast and no more than 5% of solar energy can be utilized in a single‐component TiO 2 , restricting its real application [12–14] . Thus, many efforts have been made to optimize the microstructure and composition of TiO 2 for improving its photocatalytic activity, e. g., designing nanostructure, [15,16] doping heteroatoms [17,18] and introducing co‐catalysts [19–22] …”

Section: Introductionmentioning

confidence: 99%

A 3D Hierarchical Ti₃C₂T_x/TiO₂ Heterojunction for Enhanced Photocatalytic CO₂ Reduction

Song

Cao

2021

ChemNanoMat

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The construction of three‐dimensional (3D) hierarchical photocatalysts from two‐dimensional (2D) nanosheets has attracted lots of interest due to its unique structural properties. Herein we design a 3D hierarchical structure of Ti3C2Tx based on its 2D prototype as a precursor. TiO2 is in‐situ formed on the surface of Ti3C2Tx nanosheet by calcination, thereby obtaining a 3D hierarchical TiO2/Ti3C2Tx heterojunction. The rational design induces the intimate coupling of TiO2 and Ti3C2Tx, and macro‐mesopores in the hierarchical structure. The optimized sample exhibits a relatively high photocatalytic CH4 evolution activity of 4.41 μmol ⋅ g−1 ⋅ h−1, which is almost twice that of P25 (2.32 μmol ⋅ g−1 ⋅ h−1). The enhanced photocatalytic performance arises from the more efficient electron‐hole separation and better light harvesting of the 3D hierarchical structure. Moreover, the excellent CO2 adsorption ability of Ti3C2Tx also ensures effective contact between CO2 molecules and photoinduced electrons from TiO2. This work demonstrates a facile strategy for the preparation of precursor‐induced functional materials toward various applications.

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Microwave‐Assisted Synthesis of Ultrastable Cu@TiO₂ Core‐Shell Nanowires with Tunable Diameters via a Redox‐Hydrolysis Synergetic Process

Cited by 10 publications

References 39 publications

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO₂ Hydrogenation

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO₂ Hydrogenation

Exploring Strategies toward Synthetic Precision Control within Core–Shell Nanowires

A 3D Hierarchical Ti₃C₂T_x/TiO₂ Heterojunction for Enhanced Photocatalytic CO₂ Reduction

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Microwave‐Assisted Synthesis of Ultrastable Cu@TiO2 Core‐Shell Nanowires with Tunable Diameters via a Redox‐Hydrolysis Synergetic Process

Cited by 10 publications

References 39 publications

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO2 Hydrogenation

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO2 Hydrogenation

Exploring Strategies toward Synthetic Precision Control within Core–Shell Nanowires

A 3D Hierarchical Ti3C2Tx/TiO2 Heterojunction for Enhanced Photocatalytic CO2 Reduction

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Product

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Microwave‐Assisted Synthesis of Ultrastable Cu@TiO₂ Core‐Shell Nanowires with Tunable Diameters via a Redox‐Hydrolysis Synergetic Process

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO₂ Hydrogenation

Optimized Microwave-Based Synthesis of Thermally Stable Inverse Catalytic Core–shell Motifs for CO₂ Hydrogenation

A 3D Hierarchical Ti₃C₂T_x/TiO₂ Heterojunction for Enhanced Photocatalytic CO₂ Reduction