scholarly journals Catalytic performance of surface modified-niobic acid

2018 ◽  
Vol 154 ◽  
pp. 01011
Author(s):  
Adid Adep Dwiatmoko
Keyword(s):  
Surface Modification ◽  
Phosphoric Acid ◽  
Acid Concentration ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Hydrolysis Reaction ◽  
Catalyst Selectivity ◽  
Good Relationship ◽  
Niobic Acid ◽  
Surface Modified

Surface modification of niobic acid with phosphoric acid and its catalytic performance in the hydrolysis reaction has been studied. A series of catalysts, surface-modified with different concentration of phosphoric acid, have been prepared and characterized. It was found that the catalyst selectivity to glucose increased with the increase of acid concentration used for the surface modification. The extent of selectivity enhancement of the modified catalysts showed a good relationship with the atomic ratio of phosphorous and niobium on the surface.

Production of Light Olefins Through Catalytic Cracking of C5 Raffinate Over Surface-Modified ZSM-5 Catalyst

2015 ◽  
Vol 15 (10) ◽  
pp. 8311-8317 ◽  
Author(s):  
Joongwon Lee ◽  
Seungwon Park ◽  
Ung Gi Hong ◽  
Jin Oh Jun ◽  
In Kyu Song
Keyword(s):  
Surface Modification ◽  
Catalytic Cracking ◽  
Surface Acidity ◽  
Catalytic Performance ◽  
Light Olefins ◽  
Light Olefin ◽  
Olefin Production ◽  
Chemical Liquid Deposition ◽  
Surface Modified ◽  
Teos Content

Surface modification of phosphorous-containing porous ZSM-5 catalyst (P/C-ZSM5-Sil.(X)) was carried out by a chemical liquid deposition (CLD) method using tetraethyl orthosilicate (TEOS) as a silylation agent. Different amount of TEOS (X = 5, 10, 20, and 30 wt%) was introduced into P/C-ZSM5il.(X) catalysts for surface modification. The catalysts were used for the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. It was found that external surface acidity of P/C-ZSM5-Sil.(X) catalysts significantly decreased with increasing TEOS content. In the catalytic reaction, both conversion of C5 raffinate and yield for light olefins showed volcano-shaped curves with respect to TEOS content. Among the catalysts tested, P/C-ZSM5- Sil.(20) catalyst exhibited the best catalytic performance in terms of conversion of C5 raffinate and yield for light olefins. Thus, an optimal TEOS content was required for CLD treatment to maximize light olefin production in the catalytic cracking of C5 raffinate over P/C-ZSM5-Sil.(X) catalysts.

Valence variation of phase-pure M1 MoVNbTe oxide by plasma treatment for improved catalytic performance in oxidative dehydrogenation of ethane

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91295-91301 ◽  
Author(s):  
Xin Chen ◽  
Qianli Yang ◽  
Bozhao Chu ◽  
Hang An ◽  
Yi Cheng
Keyword(s):  
Surface Modification ◽  
Metal Oxide ◽  
Plasma Treatment ◽  
Oxidative Dehydrogenation ◽  
Oxidation State ◽  
Active Sites ◽  
Oxygen Plasma ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Phase Pure

This work presents a new method of catalyst surface modification by using oxygen plasma to change the oxidation state of active sites in metal oxide catalysts.

scholarly journals Facile Preparation of Efficient WO3Photocatalysts Based on Surface Modification

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Min Liu ◽  
Hongmei Li ◽  
Yangsu Zeng
Keyword(s):  
Photocatalytic Activity ◽  
Surface Modification ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Impregnation Method ◽  
Light Spectra ◽  
Simple Strategy ◽  
Visible Light Active ◽  
Efficient Charge ◽  
Surface Modified

Tungsten trioxide (WO3) was surface modified with Cu(II) nanoclusters and titanium dioxide (TiO2) nanopowders by using a simple impregnation method followed by a physical combining method. The obtained nanocomposites were studied by scanning electron microscope, X-ray photoelectron spectroscopy spectra, UV-visible light spectra, and photoluminescence, respectively. Although the photocatalytic activity of WO3was negligible under visible light irradiation, the visible light photocatalytic activity of WO3was drastically enhanced by surface modification of Cu(II) nanoclusters and TiO2nanopowders. The enhanced photocatalytic activity is due to the efficient charge separation by TiO2and Cu(II) nanoclusters functioning as cocatalysts on the surface. Thus, this simple strategy provides a facile route to prepare efficient visible-light-active photocatalysts for practical application.

scholarly journals Enhancement of the Congo Red Adsorption Capacity of Biochars by Surface Modification with MgCl2 Pretreatment

2020 ◽  
Vol 42 (10) ◽  
pp. 472-481
Author(s):  
Hee So Oh ◽  
Jae-Soo Chang
Keyword(s):  
Surface Modification ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Congo Red ◽  
Raw Materials ◽  
Physicochemical Characteristics ◽  
Pine Sawdust ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Surface Modified

Objectives : The physicochemical characteristics of Mg-biochar composites derived from kelp and pine after pretreatment with MgCl2 were analyzed, and their adsorption capacities for an anionic dye, Congo red (CR), were evaluated.Methods : After pretreating 60 g of kelp and pine sawdust in 1 L of 0.1 M MgCl2･6H2O, the raw materials were pyrolyzed at 500℃ to produce Mg-biochar composites (kelp based KB-Mg and pine based PB-Mg). The fundamental physicochemical characteristics of the Mg-biochar composites were examined, and their adsorption capacities for CR were investigated using different initial pH values, adsorption kinetic models, and adsorption isotherm models.Results and discussion : The Mg-biochar composites showed the development of uniform deposits of Mg minerals primarily as MgO crystal on the surface by the surface modification with MgCl2. When the pristine biochars were surface-modified with MgCl2, their adsorption capacities for CR were significantly increased over the entire pH range tested. The CR adsorption process by all biochars was best described with the pseudo-first order kinetics model, and the adsorption isotherm characteristics were better described with the Langmuir isotherm model for all biochars. The Langmuir maximum adsorption capacities for KB-Mg and PB-Mg were 423.0 mg/g and 394.7 mg/g, respectively. It is suggested that the main mechanism for CR adsorption on the Mg-biochars is electrostatic attraction between CR and the biochars.Conclusions : The results showed that surface modification with MgCl2 could greatly enhance the CR adsorption capacity of biochars, and the results demonstrated the great potential of KB-Mg and PB-Mg for CR removal.

Surface modification of ferrite nanoparticles with dicarboxylic acids for the synthesis of 5-hydroxymethylfurfural: a novel and green protocol

RSC Advances ◽  
2016 ◽  
Vol 6 (80) ◽  
pp. 76795-76801 ◽  
Author(s):  
Melad Shaikh ◽  
Mahendra Sahu ◽  
Kiran Kumar Atyam ◽  
Kalluri V. S. Ranganath
Keyword(s):  
Surface Modification ◽  
Dicarboxylic Acids ◽  
Ferrite Nanoparticles ◽  
Solvent Free ◽  
Green Protocol ◽  
Flexible Ligand ◽  
Solvent Free Conditions ◽  
Surface Modified

5-Hydroxymethylfurfural (5-HMF) has been synthesized under solvent free conditions using surface modified ferrite nanoparticles. The flexible ligand modified ferrites showed higher activity than rigid modified ferrites.

Insights on the impact of photophysical processes and defect states evolution on the emission properties of surface-modified ZnO nanoplates for application in photocatalysis and hybrid LEDs

2021 ◽  
Author(s):  
Dhritiman Banerjee ◽  
Payal Banerjee ◽  
Asit Kumar Kar
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Surface Modification ◽  
Defect State ◽  
Defect States ◽  
Emission Properties ◽  
Photophysical Processes ◽  
State Densities ◽  
Surface Modified ◽  
The Impact

The effects of surface modification on the defect state densities, optical properties, photocatalytic and quantum efficiencies of zinc oxide (ZnO) nanoplates have been studied in this work. Here, the aim...

Articulating Biomaterials

2015 ◽  
pp. 218-267 ◽  
Author(s):  
Vamsi Krishna Balla ◽  
Mitun Das ◽  
Someswar Datta ◽  
Biswanath Kundu
Keyword(s):  
Surface Modification ◽  
Clinical Performance ◽  
Decisive Role ◽  
Surface Characteristics ◽  
Surface Modification Techniques ◽  
Biological Environment ◽  
Surface Modified ◽  
In Vivo Effects

This chapter examines the importance of surface characteristics such as microstructure, composition, crystallographic texture, and surface free energy in achieving desired biocompatibility and tribological properties thereby improving in vivo life of artificial articulating implants. Current implants often fail prematurely due to inadequate mechanical, tribological, biocompatibility, and osseointegration properties, apart from issues related to design and surgical procedures. For long-term in vivo stability, artificial implants intended for articulating joint replacement must exhibit long-term stable articulation surface without stimulating undesirable in vivo effects. Since the implant's surface plays a vital and decisive role in their response to biological environment, and vice versa, surface modification of implants assumes a significant importance. Therefore, overview on important surface modification techniques, their capabilities, properties of modified surfaces/implants are presented in the chapter. The clinical performance of surface modified implants and new surfaces for potential next-generation articulating implant applications are discussed at the end.

scholarly journals Preformed Pd-Based Nanoparticles for the Liquid Phase Decomposition of Formic Acid: Effect of Stabiliser, Support and Au–Pd Ratio

2020 ◽  
Vol 10 (5) ◽  
pp. 1752 ◽  
Author(s):  
Felipe Sanchez ◽  
Ludovica Bocelli ◽  
Davide Motta ◽  
Alberto Villa ◽  
Stefania Albonetti ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Formic Acid ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Phase Decomposition ◽  
Acid Effect ◽  
Formic Acid Decomposition ◽  
Structure Morphology

Hydrogen is one of the most promising energy carriers for the production of electricity based on fuel cell hydrogen technology. Recently, hydrogen storage chemicals, such as formic acid, have been proposed to be part of the long-term solution towards hydrogen economy for the future of our planet. Herein we report the synthesis of preformed Pd nanoparticles using colloidal methodology varying a range of specific experimental parameters, such as the amount of the stabiliser and reducing agent, nature of support and Pd loading of the support. The aforementioned parameters have shown to affect mean Pd particle size, Pd oxidation, atomic content of Pd on the surface as well as on the catalytic performance towards formic acid decomposition. Reusability studies were carried out using the most active monometallic Pd material with a small loss of activity after five uses. The catalytic performance based on the Au–Pd atomic ratio was evaluated and the optimum catalytic performance was found to be with the Au/Pd atomic ratio of 1/3, indicating that the presence of a small amount of Pd is essential to promote significantly Au activity for the liquid phase decomposition of formic acid. Thorough characterisation has been carried out by means of XPS, SEM-EDX, TEM and BET. The observed catalytic performance is discussed in terms of the structure/morphology and composition of the supported Pd and Au–Pd nanoparticles.

scholarly journals Influence of the surface modification by sanding of carbon textile reinforcements on the bond and load-bearing behavior of textile reinforced concrete

2019 ◽  
Vol 289 ◽  
pp. 04006
Author(s):  
Cynthia Morales Cruz ◽  
Michael Raupach
Keyword(s):  
Surface Modification ◽  
Reinforced Concrete ◽  
Tensile Tests ◽  
Measuring System ◽  
Uniaxial Tensile ◽  
Testing Time ◽  
Textile Reinforced Concrete ◽  
Load Bearing ◽  
Surface Modified ◽  
Bearing Behavior

In the context of the application of carbon Textile Reinforced Concrete (TRC) layers for the durable repair of building surfaces, uniaxial tensile tests on rectangular TRC samples were carried out to compare the bond and load-bearing behavior of an epoxy-impregnated carbon textile and its surface modified version. The aim of the surface modification, consisting of a subsequent coating with epoxy resin and sanding with quartz sand, is the improvement of the composite material regarding crack width reduction and an increase of the load-bearing capacity. A total of 15 series were examined and the parameters: reinforcement type, orientation and ratio were varied. In addition, long-term load tests were conducted. An optical 3D-video measuring system in combination with a DIC-software was used, which allowed the analysis of the process of crack formation during the entire testing time. With the surface modified reinforcement the formation of approx. 1.5 times the number of cracks with averagely 33 % smaller crack widths and up to 50 % smaller crack spacings were observed, regardless of the ratio of reinforcement. The residual behaviour of the series subjected to a permanent load of 1500 MPa over 1000 h showed no reduction of the tensile stress compared to short-term tests.

Sign in / Sign up

Export Citation Format

Share Document