Synthesis of Self-Pillared Zeolite Nanosheets by Repetitive Branching

Science ◽  
2012 ◽  
Vol 336 (6089) ◽  
pp. 1684-1687 ◽  
Author(s):  
Xueyi Zhang ◽  
Dongxia Liu ◽  
Dandan Xu ◽  
Shunsuke Asahina ◽  
Katie A. Cychosz ◽  
...  
Keyword(s):  
Reaction Rates ◽  
Hydrothermal Crystal Growth ◽  
Hierarchical Zeolites ◽  
Hierarchical Zeolite ◽  
Micropore Diffusion ◽  
Biomass Processing ◽  
One Step ◽  
Fast Transport ◽  
Improved Performance ◽  
Mfi Zeolites

Hierarchical zeolites are a class of microporous catalysts and adsorbents that also contain mesopores, which allow for fast transport of bulky molecules and thereby enable improved performance in petrochemical and biomass processing. We used repetitive branching during one-step hydrothermal crystal growth to synthesize a new hierarchical zeolite made of orthogonally connected microporous nanosheets. The nanosheets are 2 nanometers thick and contain a network of 0.5-nanometer micropores. The house-of-cards arrangement of the nanosheets creates a permanent network of 2- to 7-nanometer mesopores, which, along with the high external surface area and reduced micropore diffusion length, account for higher reaction rates for bulky molecules relative to those of other mesoporous and conventional MFI zeolites.

scholarly journals Direct, single-step synthesis of hierarchical zeolites without secondary templating

2015 ◽  
Vol 3 (3) ◽  
pp. 1298-1305 ◽  
Author(s):  
Zhuopeng Wang ◽  
Chao Li ◽  
Hong Je Cho ◽  
Shih-Chieh Kung ◽  
Mark A. Snyder ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Mass Transport ◽  
Self Assembly ◽  
Single Step ◽  
Hierarchical Zeolites ◽  
Hierarchical Zeolite ◽  
Initial Stage ◽  
Zeolite Precursors

Hierarchical ZSM-5 with a shell of stacked coffin-shaped crystals and a core of nanocrystal aggregates was synthesized by controlling the formation and self-assembly of zeolite precursors formed in the initial stage of crystallization. The formed hierarchical zeolite shows superior catalytic activity for reaction involving bulky molecules due to enhanced mass transport.

One step hydrothermal synthesis of a rGO–TiO2 nanocomposite and its application on a Schottky diode: improvement in device performance and transport properties

RSC Advances ◽  
2015 ◽  
Vol 5 (123) ◽  
pp. 101582-101592 ◽  
Author(s):  
Mrinmay Das ◽  
Joydeep Datta ◽  
Arka Dey ◽  
Rajkumar Jana ◽  
Animesh Layek ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Transport Properties ◽  
Schottky Diode ◽  
Device Performance ◽  
One Step ◽  
Improved Performance

rGO–TiO2 nanocomposite based Schottky diode shows improved performance and better transport properties compared to TiO2.

One step synthesis of ethyl levulinate biofuel by ethanolysis of renewable furfuryl alcohol over hierarchical zeolite catalyst

RSC Advances ◽  
2015 ◽  
Vol 5 (97) ◽  
pp. 79224-79231 ◽  
Author(s):  
Kakasaheb Y. Nandiwale ◽  
Ashwini M. Pande ◽  
Vijay V. Bokade
Keyword(s):  
Response Surface Methodology ◽  
Experimental Design ◽  
Response Surface ◽  
Furfuryl Alcohol ◽  
Zeolite Catalyst ◽  
Hierarchical Zeolite ◽  
Ethyl Levulinate ◽  
One Step

Response surface methodology (RSM) with Box–Behnken experimental design (BBD) demonstrated Hierarchical-HZ-5 as potential catalyst for ethanolysis of renewable furfuryl alcohol to ethyl levulinate biofuel with 99% FAL conversion and 73% EL yield.

scholarly journals Efficient Ag-Doped Perovskite Solar Cells Fabricated in Ambient Air

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1521
Author(s):  
Jiabin Hao ◽  
Zeming Wang ◽  
Huiying Hao ◽  
Guanlei Wang ◽  
Hongcheng Gao ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spin Coating ◽  
High Efficiency ◽  
Perovskite Solar Cells ◽  
Ambient Air ◽  
Nucleation Density ◽  
Perovskite Material ◽  
Coating Method ◽  
One Step ◽  
Improved Performance

So far, it is still a great challenge to prepare high efficiency organic–inorganic perovskite solar cells in ambient air. Specifically, moisture is easily combined with the perovskite material during the spin-coating process, which result in porous perovskite films with poor surface morphology. In this study, we investigated crystalline Ag-doped perovskite films by a one-step spin-coating method in air with 30–40% relative humidity (RH), in which ethyl acetate (EA) was used as antisolvent can absorb moisture in air to reduced nucleation density. More significantly, EA is a feasible and environmentally friendly solvent to replace highly toxic solvent. Moreover, 1.0% Ag-doped device shows a highest power conversion efficiency (PCE) of 14.36%. The improved performance is not only ascribed to the superior CH3NH3PbI3 film with high crystallinity but to the versatile tunability of energy band structure.

Reaktivität des labilen, durch Adduktbildung mit Ph2C=NSiMe3 gespeicherten Silaethens Me2Si=C(SiMe3)2 / Reactivity of the Labile Silaethene Me2Si = C(SiMe3)2, Stored as Ph2C =NSiMe3 Adducts

1987 ◽  
Vol 42 (9) ◽  
pp. 1062-1074 ◽  
Author(s):  
N. Wiberg ◽  
G. Preiner ◽  
G. Wagner ◽  
H. Köpf
Keyword(s):  
Reaction Rates ◽  
Ene Reactions ◽  
Reaction Intermediate ◽  
One Step

Silaethene Me2Si = C(SiMe3)2 (1), stored as Ph2C=NSiMe3 adducts and regenerated from the adducts at about 100 °C as a reaction intermediate, combines with reactants a-b (e. g. HO-H, RO-H. RCOO-H, RS-H. RHN-H, Ph2CN-H, RO-SiR3, R2N-SiR3, Ph2CN-SiR3, Cl-GeR3, Cl-SnR3) with insertion into the a-b bond, with a=b (e.g. 0 = CPh2, Me3SiN = CPh2, CH2=CHOMe, cis-piperylene), a=b=c (e.g. RN = N = N, O = N=N). a=b-c=d (e.g. butadiene, isoprene, trans-piperylene, 2,3-dimethylbutadiene, cyclopentadiene, anthracene, benzophenone, N-trimethylsilylbenzophenoneimine) under [2+2]-, [2+3]- as well as [2+A]-cycloaddition and with a=b-c-H (e.g. propene, butenes, isoprene. 2.3-dimethylbutadiene, acetone) under ene reac­tion. According to relative reaction rates, insertion and [2+2]-cycloadditions seem to proceed in two reaction steps, whereas [2+4]-cycloadditions and ene reactions with organic dienes and enes obviously are one step reactions. For relative reactivities cf. Table I.

New DRIFTS Cell Design for the Simultaneous Acquisition of IR Spectra and Kinetic Data Using On-Line Product Analysis

2001 ◽  
Vol 55 (11) ◽  
pp. 1537-1543 ◽  
Author(s):  
M. M. Schubert ◽  
T. P. Häring ◽  
G. Bräth ◽  
H. A. Gasteiger ◽  
R. J. Behm
Keyword(s):  
Co Oxidation ◽  
Gas Flow ◽  
Reaction Rates ◽  
Gas Analysis ◽  
Cell Design ◽  
Product Analysis ◽  
Kinetic Measurements ◽  
On Line ◽  
Improved Performance ◽  
Diffuse Reflectance Infrared

A new design for a DRIFTS (diffuse reflectance infrared Fourier transform spectrometry) cell for in situ studies in heterogeneous catalysis is presented, which allows for improved reaction control (i.e., gas flow, temperature, minimized background conversion) and for precise kinetic measurements via on-line gas analysis by a tandem-arranged gas chromatograph. Specifically, the very low background activity of the cell itself for CO and H2 oxidation makes it possible to study the preferential CO oxidation in H2-rich gases (PROX) at relevant reaction temperatures (150–350 °C) and reactant concentrations (≤1 kPa CO and O2). Comparison with results obtained in a quartz tube reactor shows excellent agreement with the reaction rates obtained in the DRIFTS cell. The improved performance of the new DRIFTS cell design is demonstrated by examining the influence of CO2 on the PROX reaction over a Au/Fe2O3 catalyst. The addition of CO2 to idealized reformate (varying CO and O2 partial pressures, 75 kPa H2, balance N2) significantly reduces both the CO oxidation rate and the selectivity of the PROX reaction on Au/α-Fe2O3 and strongly affects the frequency of the C–O stretch vibration of adsorbed CO due to CO2 coadsorption.

scholarly journals Hydrothermal Synthesis of Graphene Quantum Dots Supported on Three-Dimensional Graphene for Supercapacitors

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 201 ◽  
Author(s):  
Peihui Luo ◽  
Xiangfeng Guan ◽  
Yunlong Yu ◽  
Xiaoyan Li ◽  
Fengpo Yan
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Three Dimensional ◽  
Electrochemical Stability ◽  
Structure And Properties ◽  
Initial Value ◽  
One Step ◽  
Improved Performance ◽  
Functional Components ◽  
Electrodes For Supercapacitors

Incorporation of new functional components into a three-dimensional graphene (3DG) framework improves the performance of supercapacitors based on 3DG as electrodes by tailoring the framework’s structure and properties. In this work, graphene quantum dots (GQDs) were incorporated into 3DG via one-step hydrothermal treatment of GQDs and graphene oxide (GO). By simply adjusting the GQDs/GO feeding ratio by weight, various GQDs/3DG composites were formed. The maximum feeding ratio was 80%, and the prepared composites possessed saturated GQDs loading on the 3DG framework, whereas composites obtained with a GQDs/GO feeding ratio of 40% as electrodes exhibited optimal specific capacitance of 242 F·g−1 for supercapacitors, an increase of 22% compared with that of pure 3DG electrodes (198 F·g−1). This improved performance was mainly due to better electrical conductivity and larger surface area for GQDs/3DG composites with moderate GQDs content. The fabricated GQDs/3DG composites as electrodes for supercapacitors revealed high electrochemical stability. Their capacitance kept 93% of the initial value after 10,000 charge-discharge cycles.

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