O4 Nanorods Research Articles

Tailoring the Supercapacitance of Hydrothermally Synthesized Co3O4 Nanorods via Ni‐Doping and Fabrication of Symmetric and Asymmetric Supercapacitors

Herein, cost‐effective and highly efficient Co3−XNiXO4 electrodes with various Ni concentrations (X = 0.1 to 0.5) are synthesized for supercapacitors. Ni‐doping effects are elucidated by various structural, morphological, and spectroscopic characterizations. The electrochemical studies show a ≈2‐fold increase in the specific capacitance for X = 0.5 when compared to its pristine counterpart. With varying concentrations of Ni, the specific capacitance of Co3O4, Co3−0.2Ni0.2O4, Co3−0.5Ni0.5O4 nanorods exhibits 473, 657, and 892 Fg−1 at a current density of 1 Ag−1 with a capacitance retention rate of 94%, 91%, and 93%, respectively, up to 8000 cycles. Significant enhancement in specific capacitance without compromising the cycling stability is due to the low charge transfer and internal resistances. Symmetric and asymmetric supercapacitors are fabricated using the sample with maximum performance, i.e., X = 0.5. The symmetric supercapacitor exhibits a specific capacitance of 222 Fg−1 at 1 Ag−1 and a capacitance retention of 89.3% over 1000 cycles at 5 Ag−1. For the asymmetric supercapacitor (ASC) fabrication, Co3Ni0.5O4 and activated carbon are used as positive and negative electrodes, respectively. The ASC device shows an excellent energy density of 39.4 Wh kg−1 at a power density of 754.8 Wh kg−1 with a retention rate of 98.4%.

Morphological, structural, optical and photocurrent characteristics of Bi(TixMn(1-x))O3 perovskite nanorods grown by hydrothermal synthesis

This study focuses on the hydrothermal synthesis of Bi(TixMn(1-x))O3 (x = 0.3–0.9) perovskite nanorods on fluorine-doped tin oxide glass substrates and investigates the influence of Ti4+ on their morphological, structural, optical properties, and photocatalytic behavior. The high-resolution XPS spectra results have proved that Ti has been properly substituted into the Bi(TixMn(1-x))O3 nanorods. The characterization of morphology reveals a decrease in average diameter from 222 to 115 nm as the Ti concentration increases, while the band-gap energy experiences a slight reduction from 3.158 to 3.132 eV. X-ray and Raman spectroscopy analyses of the Bi(TixMn(1-x))O3 nanorods indicate that Ti ions substitute not only Mn3+ but also Bi3+ ions, leading to structural distortions in the crystal lattice. Moreover, the Bi(TixMn(1-x))O3 systems demonstrate enhanced photocurrent densities at 1.5 V potential, ranging from 3.19 to 5.54 mA/cm2, as the Ti concentration increases. This enhancement can be attributed to the combined effects of increased surface area, accelerating electron transfer at the interface of the electrode, and decreased optical band-gap energy. It is anticipated that this novel system will pave the way for further advancements in the field of photocatalytic water splitting and solar energy conversion applications.

Oxygen Vacancy Induced Strong Metal-Support Interactions on Ni/Ce0.8Zr0.2O2 Nanorod Catalysts for Promoting Steam Reforming of Toluene: Experimental and Computational Studies.

To develop an efficient Ni-based steam reforming catalyst for tar removal from the products of biomass gasification, Ni/Ce0.8Zr0.2O2 nanorods were designed. The Ni/Ce0.8Zr0.2O2 nanorod was used as a catalyst in steam reforming of toluene, which was regarded as a model compound of biomass gasification tar. At gas hourly space velocity (GHSV) of 24,000 h-1 and Ni loading of 5 wt %, the 5Ni/Ce0.8Zr0.2O2 nanorod catalyst achieved 100% of toluene conversion at 600 °C. After 10 h of operation, toluene conversion still reached 87.6%, and the carbon deposition rate was only 1.9 mg/gcat h-1. The experimental results demonstrated that the 5Ni/Ce0.8Zr0.2O2 nanorod catalyst showed much higher catalytic activity and coking resistance than other Ni-based catalysts reported in the literature. Through different characterization technologies and density functional theory calculations, it was confirmed that the excellent catalytic performance was attributed to the strong metal-support interaction (SMSI) between Ni and the {100} facet of Ce0.8Zr0.2O2. The special surface structure of {100} allowed Ni atoms to anchor to the surface oxygen vacancies and maintained its reduced state by electron transport between surface atoms. The anchored Ni facilitated oxygen vacancies formation and H2O dissociation on the support, while the support modulated the electronic structure of Ni, which promoted its ability to toluene activation.

Distinct morphology-dependent behaviors for Au/γ-Al2O3 catalysts: enhanced thermal stabilization in CO oxidation reaction.

The durability of supported metal catalysts usually suffers from sintering, the metal nanoparticles aggregating into larger sizes and subsequent loss of reactive surface, resulting in catalysts deactivation when heated at elevated temperatures. Herein, we investigate the evolution of Au species on different morphologies of γ-Al2O3 and surprisingly found vastly different behavior for the dispersion of surface Au nanoparticles. A nanorod-shaped γ-Al2O3 is prepared by the hydrothermal method resulting in an extraordinary catalyst support that can stabilize Au nanoparticles at annealing temperatures up to 700 °C. In contrast, the Au-supported catalyst prepared using commercial γ-Al2O3 shows a greater degree of inactivation under the same conditions. Remarkably, the unique morphology of such nanorod-shaped γ-Al2O3 is beneficial in preventing Au nanoparticles from sintering. The γ-Al2O3 nanorods are more effective than the commercial γ-Al2O3 at anchoring the Au nanoparticles. The results of X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and H2-TPR, reveal the interfacial interactions between Au nanoparticles and γ-Al2O3 nanorods, yielding a sinter-stability of the obtained Au/γ-Al2O3 nanorods catalyst. This synthetic strategy is simple and amenable to the large-scale manufacture of thermally stable γ-Al2O3 for industrial applications. Here, we investigate the morphology-dependent behavior of Au nanoparticles dispersed on different morphologies of γ-Al2O3. The result of X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and H2-TPR, reveal the interfacial interactions between Au nanoparticles and gamma alumina nanorods. Au nanoparticles on γ-Al2O3 nanorods exhibit higher sinter-resistant performance than those on commercial γ-Al2O3.

Effects of Mg-doping on distorted structure and enhanced electrochemical performance of V1-Mg O2 nanorods

In this work, a series of V1-xMgxO2 samples (x = 0–0.030) were synthesized by hydrothermal method. The corresponding laws of Mg2+ doping concentration on the microstructures and electrochemical performance of V1-xMgxO2 were studied in detail. The XRD results indicated that the prepared V1-xMgxO2 samples showed monoclinic crystal phase and Mg2+ doping caused lattice distortion in the experimental doping range. The SEM and TEM results showed that all the V1-xMgxO2 samples were nanorods and well-crystallized. The positron lifetime spectra showed that the main defects in the V1-xMgxO2 samples were vacancy clusters. The concentration and size of the defects were affected by the combined action of ion radius and valence state of doped Mg2+. The electrochemical results revealed that the samples showed better electrochemical properties when the Mg2+ doping concentration x is 0.015. The high discharge capacitance of the x = 0.015 sample reached 140.6 F/g and the capacitor retention of this sample was still about 90 % after 1000 cycles.

3D Porous Compact 1D/2D Fe2 O3 /MXene Composite Aerogel Film Electrodes for All-Solid-State Supercapacitors.

2D MXene nanoflakes usually undergo serious restacking, that easily aggravates during the traditional vacuum-assisted filtration process; and thus, hinders the electrochemical performance of the corresponding film electrodes. Herein, 3D porous compact 1D/2D Fe2 O3 /MXene aerogel film electrode with an enhanced electrochemical performance is fabricated by freeze-drying assisted mechanical pressing. An introduction of 1D α-Fe2 O3 nanorods can not only alleviate the restacking of 2D MXene but also provide additional pseudocapacitance for the composite film system. Thus, the resulting Fe2 O3 /MXene aerogel film electrode shows an enhanced specific capacitance of 182 F g-1 (691 mF cm-2 ) at a current density of 1 A g-1 in 3 m H2 SO4 electrolyte as well as with 81.74% capacitance retention after 10000 charge-discharge cycles. Besides, the addition of 1D α-Fe2 O3 nanorods has a significant contribution in the volumetric capacitance of the composite aerogel film (150 F cm-3 ), which is 2.68 times that of the pure MXene aerogel film (56 F cm-3 ). Moreover, the fabricated all-solid-state symmetric supercapacitor (SSSC) delivers a superior areal energy density of 3.61 µWh cm-2 at a power density of 119.04 µW cm-2 . This rapid-forming 3D porous, binder-free, and freestanding aerogel film provides a progressive strategy for the fabrication of MXene-based electrode for supercapacitors.

Effect of O2 on Selective Catalytic Reduction of NO by C3H6 over Fe Catalysts Supported on Porous Clay Heterostructures (Fe-PCH)

K10 montmorillonite was used as the raw clay to prepare porous clay heterostructures (PCH) by organic template intercalation and tetraethylorthosilicate (TEOS) was used as silicone source. Fe was load on the PCH support by impregnation method to prepare Fe-PCH catalysts. The catalytic activity tests were carried out in a fixed bed micro-reactor in the atmosphere of 0.1% C3 H6 , 0.1%NO, 0~10%O2 in N2 balance. The total flow rate was 100ml/min and corresponding gas hourly space velocity (GHSV) was 15000h-1. The mircro-reaction pathways were studied by Diffuse Reflection Infrared Fourier Transform Spectrometer (DRIFTS). The influence of O2 on the SCR-C3 H6 reactivity over Fe-PCH was analyzed. The results showed that FePCH catalyst exhibited the best catalytic performance without oxygen, which reached the maximum NO conversion of 100% at 4000 C. When the concentration of O2 is below a critical value, [O2 ]crit, the catalytic activity gradually decreased with the increasing concentration of O2 . When the concentration of O2 is above [O2 ]crit, the NO conversion was only 20%~30%. Fe-PCH catalysts were characterized by transmission electron microscope (TEM), N2 adsorption/desorption and X-ray photoelectron spectroscopy (XPS) techniques. The results showed that Fe-PCH had supermicroporous and mesoporous structures. The active components on Fe-PCH catalyst were mainly α-Fe2 O3 nanorods, exposing (024) and (104) planes. The in situ DRIFTS technique was used to detect the reactive intermediates over the surface of Fe-PCH catalyst, which could help analyze the mechanism of the influence of oxygen on catalytic activity. The results presented that oxygen could inhibit the formation of isocyanate species over Fe-PCH catalyst during C3 H6 -SCR, which might be the reason for the decrease of NO conversion. Finally, a reasonable reaction path of C3 H6 -SCR over Fe-PCH catalyst was proposed.

(Digital Presentation) Cobalt Free Cathode Synthesized By Sacrificial Template (α-MnOOH) for Rechargeable Lithium Batteries

LiCoO2 cathode has been used widely for Li-ion batteries (LIBs) for portable applications due to it is compactness, high energy density, excellent cycle life and reliability [1]. Nevertheless, the high cost of cobalt represent some of the limitations of this material [1]. As an alternative, LiNiO2, which iso-structural with LiCoO2, is reported as a stable material for LIB cathodes. Although, the poor thermal stability of this material in operating LIB represents safety risk [2]. On the other hand, LiMnO2 has also been proposed as a low-cost cathode for LIB. However, it is not stable during charging/discharging processes [3]. Ni-rich layer oxide (LiM1-x NxiO2, where M is a transition metal, x > 0.8) appeared as result of much effort dedicated for finding an adequate balance between cost and stability [4]. In comparison to Ni-rich layer, Li-rich layer oxide exhibited better cyclability and safety performance at higher electrode potentials (>4.5 V vs. Li|Li+) [4]. However, the structural and electrochemical properties of the as-prepared materials are determined by the synthesis methods and/or preparation conditions [5]. For instance, the electrochemical performance of Li1.5Ni0.25Mn0.75O2.5 layer material obtained by a simple carbonate coprecipitation method was improved with 240 mAh g-1 and 70.3% of capacity retention after 30 cycles at 0.05C [6].In this work, we report the feasibility of producing a cobalt free cathode LiNi0.5Mn0.5O2 with high energy density using a sacrificial template α -MnOOH as precursor with a simple balance between lithium and nickel content. The synthesis strategies performed in this work led to a promising cathode material with high energy density without sacrificing the operating voltage window, by combining our understanding of the factors governing the cation order with a facile synthetic route that ensured good cation mixing.The LiNi0.5Mn0.5O2 active cathode material was produced by co-precipitated method according to the following procedure: α-MnOOH sacrificial template was synthesized according to ref. [7].Then active cathode material was obtained by co-precipitation method using α-MnOOH, lithium acetate and nickel acetate with a molar ratio of 0.5:1.05:0.5 mol at different treatment temperatures (700°C, 800°C and 900°C). Rate capabilities of all samples are displayed in Fig. 1. The charge-discharge current was increased from 20 mA g-1 (0.1C) to 2000 mA g-1 (10C), and then decreased back to 20 mA g-1. The Li1.05Ni0.5Mn0.5O2 material displayed the best electrochemical performance at 800°C which the initial discharge capacity was 179.9 mAh g-1 . The other samples at 700 °C and 900 °C showed initial discharge capacities of 171.3 mAh g-1 and 156.4 mAh g-1 at 0.1C, respectively. On the other hand, α-MnOOH sacrificial template synthesis showed to be a plausible formation mechanism and the structure–function relationships of LiNi0.5Mn0.5O2.[1] N. Nitta, F. Wu, J. T. Lee, and G. Yushin, “Li-ion battery materials: present and future,” Mater. Today, vol. 18, no. 5, pp. 252–264, Jun. 2015.[2] M. Bianchini, M. Roca-Ayats, P. Hartmann, T. Brezesinski, and J. Janek, “There and Back Again—The Journey of LiNiO2 as a Cathode Active Material,” Angew. Chemie Int. Ed., vol. 58, no. 31, pp. 10434–10458, Jul. 2019.[3] T. Ohzuku and Y. Makimura, “Layered Lithium Insertion Material of LiNi 1/2 Mn 1/2 O 2 : A Possible Alternative to LiCoO 2 for Advanced Lithium-Ion Batteries,” Chem. Lett., vol. 30, no. 8, pp. 744–745, Aug. 2001.[4] G. Hu et al., “A facile cathode design with a LiNi0.6Co0.2Mn0.2O2 core and an AlF3-activated Li1.2Ni0.2Mn0.6O2 shell for Li-ion batteries,” Electrochim. Acta, vol. 265, pp. 391–399, Mar. 2018.[5] C. Zhao, X. Wang, R. Liu, F. Xu, and Q. Shen, “β-MnO2 sacrificial template synthesis of Li 1.2Ni0.13Co0.13Mn0.54O2 for lithium ion battery cathodes,” RSC Adv., vol. 4, no. 14, pp. 7154–7159, Jan. 2014.[6] M. Akhilash, P. S. Salini, K. Jalaja, B. John, and T. D. Mercy, “Synthesis of Li1.5Ni0.25Mn0.75O2.5 cathode material via carbonate co-precipitation method and its electrochemical properties,” Inorg. Chem. Commun., vol. 126, p. 108434, Apr. 2021.[7] F. A. Vásquez, J. E. Thomas, A. Visintin, and J. A. Calderón, “LiMn1.8Ni0.2O4 nanorods obtained from a novel route using α-MnOOH precursor as cathode material for lithium-ion batteries,” Solid State Ionics, vol. 320, pp. 339–346, Jul. 2018. Figure 1

Synthesis of Li1.2Mn0.54Ni0.13Co0.13O2 Nanorods by a Facile Self-Template Method and their Electrochemical Performances

Lithium-rich manganese-based oxides have become one of the widely studied cathode materials for lithium-ion batteries due to their high-energy density, relatively low price and environmental friendliness. Herein, we propose a simple self-template route to prepare [Formula: see text][Formula: see text][Formula: see text][Formula: see text]O2 nanorods using rod-like Mn2O3 as templates. Besides, the effect of calcination temperature on the morphology and electrochemical properties of the electrode materials was investigated. [Formula: see text][Formula: see text][Formula: see text][Formula: see text]O2 nanorods as the cathode exhibit initial capacity of 251.4 mAh gt1 at 0.1 C and capacity retention rate of 67.9% after 200 cycles, which can be attributed to the enhanced layered structural stability, lower charge transfer resistance and shorter lithium-ion transport pathway.

Facile, sustainable and unassisted plain water oxidation on Au/Ce0.9Ti0.1O2 nanorods in direct sunlight

Facile, sustainable and unassisted plain water oxidation on Au/Ce0.9Ti0.1O2 nanorods in direct sunlight

All-in-one asymmetric micro-supercapacitor with Negative Poisson's ratio structure based on versatile electrospun nanofibers

It is very necessary to design electrodes with satisfactory electrochemical performance and robust mechanical properties for flexible energy storage devices. Herein, a self-supporting electrode with Negative Poisson's Ratio (NPR) structure was fabricated by combining electrospinning and laser direct writing technology, which overcame the limitation that the traditional carbon-based materials cannot be stretched and avoided the integration problem of rigid electrodes and soft substrates in the conventional stretchable devices. Furthermore, a quasi-solid-state asymmetric micro-supercapacitor with NPR structure was assembled by an as-spun separator coated with gel electrolyte and two composite electrodes composed of carbon nanofibers and nanoarrays ([email protected]2O3 nanorods and [email protected]2 nanosheets). The apparatus not only reached an extended voltage window of 2 V, but also achieved an area energy density of 26 μWh·cm−2 at a power density of 0.55 mW·cm−2, which was superior to other wearable micro-supercapacitors.

Self-standing Co2.4Sn0.6O4 nano rods as high performance anode materials for sodium-ion battery and investigation on its reaction mechanism

The self-standing nanorod Co2.4Sn0.6O4 is synthesized as a high-performance anode material in search of high capacity and stable anode materials for sodium-ion batteries. The Co2.4Sn0.6O4 nanorod exhibits a high reversible capacity of 576 mAh g−1 at a current density of 80 mA g−1 and shows excellent high-rate capability. The X-ray absorption spectroscopy study reveals the mechanisms of charge storage reaction and improved cycling performance of Co2.4Sn0.6O4. A partially limited conversion reaction of Co– and Sn-oxide during the cycling effectively regulate the irreversible capacity loss over the cycling that is commonly observed from the conversion and alloying reaction-based anode materials. Furthermore, Co2.4Sn0.6O4 also exhibits superior sodium-ion full cell performance when coupled with a NaNi2/3Bi1/3O2 cathode, demonstrating an energy density of 262 Wh kg−1.

Self-Standing Co2.4sn0.6o4 Nano Rods as High Performance Anode Materials for Sodium-Ion Battery and Investigation on its Reaction Mechanism

Self-Standing Co2.4sn0.6o4 Nano Rods as High Performance Anode Materials for Sodium-Ion Battery and Investigation on its Reaction Mechanism

Cobalt Free Cathode Synthesized By Sacrificial Template (α-MnOOH) for Rechargeable Lithium Batteries

Cobalt Free Cathode Synthesized by Sacrificial Template (α -MnOOH) for Rechargeable Lithium Batteries LiCoO2 cathode has been used widely for Li-ion batteries (LIBs) for portable applications due to it is compactness, high energy density, excellent cycle life and reliability [1]. Nevertheless, the high cost of cobalt represent some of the limitations of this material [1]. As an alternative, LiNiO2, which iso-structural with LiCoO2, is reported as a stable material for LIB cathodes. Although, the poor thermal stability of this material in operating LIB represents safety risk [2]. On the other hand, LiMnO2 has also been proposed as a low-cost cathode for LIB. However, it is not stable during charging/discharging processes [3]. Ni-rich layer oxide (LiM1-x NxiO2, where M is a transition metal, x > 0.8) appeared as result of much effort dedicated for finding an adequate balance between cost and stability [4]. In comparison to Ni-rich layer, Li-rich layer oxide exhibited better cyclability and safety performance at higher electrode potentials (>4.5 V vs. Li|Li+) [4]. However, the structural and electrochemical properties of the as-prepared materials are determined by the synthesis methods and/or preparation conditions [5]. For instance, the electrochemical performance of Li1.5Ni0.25Mn0.75O2.5 layer material obtained by a simple carbonate coprecipitation method was improved with 240 mAh g-1 and 70.3% of capacity retention after 30 cycles at 0.05C [6].In this work, we report the feasibility of producing a cobalt free cathode LiNi0.5Mn0.5O2 with high energy density using a sacrificial template α -MnOOH as precursor with a simple balance between lithium and nickel content. The synthesis strategies performed in this work led to a promising cathode material with high energy density without sacrificing the operating voltage window, by combining our understanding of the factors governing the cation order with a facile synthetic route that ensured good cation mixing.The LiNi0.5Mn0.5O2 active cathode material was produced by co-precipitated method according to the following procedure: α-MnOOH sacrificial template was synthesized according to ref. [7].Then active cathode material was obtained by co-precipitation method using α-MnOOH, lithium acetate and nickel acetate with a molar ratio of 0.5:1.05:0.5 mol at different treatment temperatures (700°C, 800°C and 900°C). Rate capabilities of all samples are displayed in Fig. 1. The charge-discharge current was increased from 20 mA g-1 (0.1C) to 2000 mA g-1 (10C), and then decreased back to 20 mA g-1. The Li1.05Ni0.5Mn0.5O2 material displayed the best electrochemical performance at 800°C which the initial discharge capacity was 179.9 mAh g-1 . The other samples at 700 °C and 900 °C showed initial discharge capacities of 171.3 mAh g-1 and 156.4 mAh g-1 at 0.1C, respectively. On the other hand, α-MnOOH sacrificial template synthesis showed to be a plausible formation mechanism and the structure–function relationships of LiNi0.5Mn0.5O2.[1] N. Nitta, F. Wu, J. T. Lee, and G. Yushin, “Li-ion battery materials: present and future,” Mater. Today, vol. 18, no. 5, pp. 252–264, Jun. 2015.[2] M. Bianchini, M. Roca-Ayats, P. Hartmann, T. Brezesinski, and J. Janek, “There and Back Again—The Journey of LiNiO2 as a Cathode Active Material,” Angew. Chemie Int. Ed., vol. 58, no. 31, pp. 10434–10458, Jul. 2019.[3] T. Ohzuku and Y. Makimura, “Layered Lithium Insertion Material of LiNi 1/2 Mn 1/2 O 2 : A Possible Alternative to LiCoO 2 for Advanced Lithium-Ion Batteries,” Chem. Lett., vol. 30, no. 8, pp. 744–745, Aug. 2001.[4] G. Hu et al., “A facile cathode design with a LiNi0.6Co0.2Mn0.2O2 core and an AlF3-activated Li1.2Ni0.2Mn0.6O2 shell for Li-ion batteries,” Electrochim. Acta, vol. 265, pp. 391–399, Mar. 2018.[5] C. Zhao, X. Wang, R. Liu, F. Xu, and Q. Shen, “β-MnO2 sacrificial template synthesis of Li 1.2Ni0.13Co0.13Mn0.54O2 for lithium ion battery cathodes,” RSC Adv., vol. 4, no. 14, pp. 7154–7159, Jan. 2014.[6] M. Akhilash, P. S. Salini, K. Jalaja, B. John, and T. D. Mercy, “Synthesis of Li1.5Ni0.25Mn0.75O2.5 cathode material via carbonate co-precipitation method and its electrochemical properties,” Inorg. Chem. Commun., vol. 126, p. 108434, Apr. 2021.[7] F. A. Vásquez, J. E. Thomas, A. Visintin, and J. A. Calderón, “LiMn1.8Ni0.2O4 nanorods obtained from a novel route using α-MnOOH precursor as cathode material for lithium-ion batteries,” Solid State Ionics, vol. 320, pp. 339–346, Jul. 2018. Figure 1

Facet-Dependent Biodegradable Mn3 O4 Nanoparticles for Ameliorating Parkinson's Disease.

Parkinson's disease (PD) is a common neurodegeneration disease. Unfortunately, there are no effective measures to prevent or inhibit this disease. In this study, biodegradable Mn3 O4 nanoparticles (NPs) in different shapes are prepared and enclosed them by {100}, {200} and {103} facets that exhibit facet-dependent protection against neurotoxicity induced by oxidative damage in a cell model of PD. Notably, Mn3 O4 nanorods enclosed by {103} facets exhibit high levels of enzyme-like activity to eliminate reactive oxygen specie in vitro. It is also determined that the uptake pathway of Mn3 O4 NPs into MN9D cells is mediated by caveolin. The data demonstrate that Mn3 O4 nanorods can be taken up by cells effectively and confer excellent levels of neuroprotection while the biodegradation of Mn3 O4 NPs in vivo is confirmed by photoacoustic image of Mn3 O4 NPs in brain at 60 d. Furthermore, the oxygen scavenging effect created by Mn3 O4 nanorods is successfully applied to a mouse model of PD; the amount of α-synuclein in the cerebrospinal fluid of PD mice is reduced by 61.2% in two weeks, thus demonstrating the potential application of facet-directed Mn3 O4 NPs for the clinical therapy of neurodegenerative disease.

MOFs-Derived Fusiform In2 O3 Mesoporous Nanorods Anchored with Ultrafine CdZnS Nanoparticles for Boosting Visible-Light Photocatalytic Hydrogen Evolution.

The development of efficient visible-light-driven photocatalysts is one of the critically important issues for solar hydrogen production. Herein, high-efficiency visible-light-driven In2 O3 /CdZnS hybrid photocatalysts are explored by a facile oil-bath method, in which ultrafine CdZnS nanoparticles are anchored on NH2 -MIL-68-derived fusiform In2 O3 mesoporous nanorods. It is disclosed that the as-prepared In2 O3 /CdZnS hybrid photocatalysts exhibit enhanced visible-light harvesting, improves charges transfer and separation as well as abundant active sites. Correspondingly, their visible-light-driven H2 production rate is significantly enhanced for more than 185 times to that of pristine In2 O3 nanorods, and superior to most of In2 O3 -based photocatalysts ever reported, representing their promising applications in advanced photocatalysts.

The Hole-Tunneling Heterojunction of Hematite-Based Photoanodes Accelerates Photosynthetic Reaction.

Single-atom metal-insulator-semiconductor (SMIS) heterojunctions based on Sn-doped Fe2 O3 nanorods (SF NRs) were designed by combining atomic deposition of an Al2 O3 overlayer with chemical grafting of a RuOx hole-collector for efficient CO2 -to-syngas conversion. The RuOx -Al2 O3 -SF photoanode with a 3.0 nm thick Al2 O3 overlayer gave a >5-fold-enhanced IPCE value of 52.0 % under 370 nm light irradiation at 1.2 V vs. Ag/AgCl, compared to the bare SF NRs. The dielectric field mediated the charge dynamics at the Al2 O3 /SF NRs interface. Accumulation of long-lived holes on the surface of the SF NRs photoabsorber aids fast tunneling transfer of hot holes to single-atom RuOx species, accelerating the O2 -evolving reaction kinetics. The maximal CO-evolution rate of 265.3 mmol g-1 h-1 was achieved by integration of double SIMS-3 photoanodes with a single-atom Ni-doped graphene CO2 -reduction-catalyst cathode; an overall quantum efficiency of 5.7 % was recorded under 450 nm light irradiation.

Enhanced Photoelectrochemical Water Oxidation Performance in Bilayer TiO2 /α-Fe2 O3 Nanorod Arrays Photoanode with Cu : NiOx as Hole Transport Layer and Co-Pi as Cocatalyst.

Efficient charge transfer and excellent surface water oxidation kinetics are key factors in determining the photoelectrochemical (PEC) water splitting performance in photoelectrodes. Herein, a bilayer TiO2 /α-Fe2 O3 nanorod (NR) arrays photoanode was prepared with deposited Cu-doped NiOx (Cu : NiOx ) hole transport layer (HTL) and Co-Pi oxygen evolution reaction (OER) cocatalyst for PEC water oxidation. The hierarchical TiO2 /α-Fe2 O3 composite obtained by a secondary hydrothermal process exhibited an inapparent bilayer structure by embedding the underlayer TiO2 NR arrays at the bottom part of the post-grown α-Fe2 O3 NR arrays. The underlayer TiO2 NRs acted as an effective shuttling pathway for transferring photoelectrons generated in the upper hematite light absorber layer. A p-type inter-Cu : NiOx HTL was introduced to form a build-in p-n electric field between Cu : NiOx and α-Fe2 O3 NRs, which improved the hole extraction from α-Fe2 O3 to Co-Pi OER catalyst. As expected, the as-engineered TiO2 /α-Fe2 O3 /Cu : NiOx /Co-Pi photoanode displayed an excellent photocurrent density of 2.43 mA cm-2 at 1.23 V versus the reversible hydrogen electrode (VRHE ), up to 4.05 and 2.23 times greater than those of the bare α-Fe2 O3 (0.60 mA cm-2 ) and TiO2 /α-Fe2 O3 , respectively. The results demonstrate that the bottom-up engineering of electron-hole transport channels and cocatalyst modification is an attractive maneuver to enhance the PEC water oxidation activity in hematite and other photoanodes.

Enhanced figure of merit in Pb(Zr,Ti)O3 nanorods for piezoelectric energy harvesting

Piezoelectric energy harvesting based on nanorod arrays has attracted attention owing to the simple structure that has the potential to generate large output power. The decreased density of the nanorod array, compared to that of typical piezoelectric films, should achieve a larger figure of merit (FOM). However, the effect of the density of the nanorod array has been scarcely validated by direct experiments. In this study, we fabricated Pb(Zr,Ti)O3 nanorods by using an elevated growth rate during pulsed laser deposition and compared them with the film. The nanorods have the a/c-domain structure, which is consistent with the reference film, leading to a similar piezoelectric response. The lowered density of the nanorods caused an appreciable reduction in the effective dielectric constant, which significantly increased the effective FOM. As a result, FOM and available energy of the nanorods were 61% improved, compared to those of the film. The enhanced FOM of the nanorod indicates the prospective application of piezoelectric energy harvesting in off-resonant vibration environments.

Hydrostatic contraction and anisotropic contraction effects on oxygen molecule nanorods

We study the effects of both hydrostatic and anisotropic contractions on the molecular condensation of oxygen molecules (O2) physisorbed to nanosized pores, termed “O2 nanorods”, through the magnetization measurements. Multisteps of O2 solidification accompany the reduction in structural symmetry with decreasing temperature, such that the structural change by external stress varies the stability of O2 solidification. For initial pore diameters of D = 8.5, 14.5, and 24.0 nm, anisotropic compression for nanorods (preferential compression along radial direction of the pores) occurred, and molecule solidification is suppressed at the lower temperature side compared with that under hydrostatic compression. For the smallest D = 6.5 nm, a hydrostatic contraction almost occurred, and the high adsorption capability enabled the detection of both the melting transition and change in crystal structure within the β phase, in addition to α–β and β–γ transitions.