Recent Progress in Improving the Oxidation of Formic Acid on High Surface Area Platinum and Palladium Catalysts: Surface Alloying and pH Effects

2019 ◽  
Vol 16 (2) ◽  
pp. 627-638 ◽  
Author(s):  
John L. Haan ◽  
Richard I. Masel
Keyword(s):  
Formic Acid ◽  
Surface Area ◽  
Palladium Catalysts ◽  
Recent Progress ◽  
High Surface ◽  
High Surface Area ◽  
Ph Effects ◽  
Surface Alloying

scholarly journals Enhancement of Photocatalytic Oxidation of Glucose to Value-Added Chemicals on TiO2 Photocatalysts by A Zeolite (Type Y) Support and Metal Loading

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 423 ◽  
Author(s):  
Kamonchanok Roongraung ◽  
Surawut Chuangchote ◽  
Navadol Laosiripojana
Keyword(s):  
Formic Acid ◽  
Surface Area ◽  
Gluconic Acid ◽  
Photocatalytic Oxidation ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Value Added ◽  
Incipient Wetness Impregnation ◽  
Microwave Assisted

TiO2-based photocatalysts synthesized by the microwave-assisted sol-gel method was tested in the photocatalytic glucose conversion. Modifications of TiO2 with type-Y zeolite (ZeY) and metals (Ag, Cu, and Ag-Cu) were developed for increasing the dispersion of TiO2 nanoparticles and increasing the photocatalytic activity. Effects of the TiO2 dosage to zeolite ratio (i.e., TiO2/ZeY of 10, 20, 40, and 50 mol %) and the silica to alumina ratio in ZeY (i.e., SiO2:Al2O3 of 10, 100, and 500) were firstly studied. It was found that the specific surface area of TiO2/ZeY was 400–590 m2g−1, which was higher than that of pristine TiO2 (34.38 m2g−1). The good properties of 20%TiO2/ZeY photocatalyst, including smaller particles (13.27 nm) and high surface area, could achieve the highest photocatalytic glucose conversion (75%). Yields of gluconic acid, arabinose, xylitol, and formic acid obtained from 20%TiO2/ZeY were 9%, 26%, 4%, and 35%, respectively. For the effect of the silica to alumina ratio, the highest glucose conversion was obtained from SiO2:Al2O3 ratio of 100. Interestingly, it was found that the SiO2:Al2O3 ratio affected the selectivity of carboxylic products (gluconic acid and formic acid). At a low ratio of silica to alumina (SiO2:Al2O3 = 10), higher selectivity of the carboxylic products (gluconic acid = 29% and formic acid = 32%) was obtained (compared with other higher ratios). TiO2/ZeY was further loaded by metals using the microwave-assisted incipient wetness impregnation technique. The highest glucose conversion of 96.9 % was obtained from 1 wt. % Ag-TiO2 (40%)/ZeY. Furthermore, the bimetallic Ag-Cu-loaded TiO2/ZeY presented the highest xylitol yield of 12.93%.

Palladium catalysts supported on carbon–nitrogen composites for aqueous-phase hydrogenation of phenol

2015 ◽  
Vol 5 (4) ◽  
pp. 2300-2304 ◽  
Author(s):  
Gang Feng ◽  
Ping Chen ◽  
Hui Lou
Keyword(s):  
Surface Area ◽  
Aqueous Phase ◽  
Palladium Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Supported Palladium Catalysts ◽  
Highly Active ◽  
Supported Palladium

Supported palladium catalysts on carbon-nitrogen composites with high surface area are highly active for aqueous-phase hydrogenation of phenol.

Rapid and Efficient Synthesis of Platinum Nanodendrites with High Surface Area by Chemical Reduction with Formic Acid

2010 ◽  
Vol 22 (9) ◽  
pp. 2835-2841 ◽  
Author(s):  
Liang Wang ◽  
Hongjing Wang ◽  
Yoshihiro Nemoto ◽  
Yusuke Yamauchi
Keyword(s):  
Formic Acid ◽  
Surface Area ◽  
Chemical Reduction ◽  
High Surface ◽  
High Surface Area ◽  
Efficient Synthesis

scholarly journals A Review of the State of the Art towards Biological Applications of Graphene-based Nanomaterials

2021 ◽  
pp. 216-230
Author(s):  
Varun Kumar Sharma ◽  
Mohd Yusuf ◽  
Prem Kumar ◽  
. Sheeba ◽  
. Nafisa ◽  
...  
Keyword(s):  
Gene Delivery ◽  
Surface Area ◽  
Recent Progress ◽  
State Of The Art ◽  
High Surface ◽  
High Surface Area ◽  
The State ◽  
Biological Applications ◽  
The Past ◽  
Delivery Vehicles

The field of nanoscience has evolved into a wide variety of successes over the past two decades and the emphasis on nanotechnology is to revolve around various dynamic fields, such as sensor, biomedical, and many useful applications. Advances in related fields are certainly due to the ability to synthesize nanoparticles from a variety of materials, structures, and to convert samples into complex nanoarchitectures. The promises of nanomedicine are broad. Graphene (Gr), the first 2-dimensional material to stand alone, is a type of new nanomaterial that leads to the excitement of natural biological applications. Number of researches has been conducted on applicability of GBNs in the area of environment, biomedical, and healthcare sectors. As compared to other nanomaterials, extraordinary properties of graphene-based nanomaterials (GBNs) like high surface area, multilayers, multifunctional and excellent biocompatibility make them capable to play great roll of highly-tailored multifunctional delivery vehicles for drugs delivery, gene delivery, phototherapy and bioimaging. However, research communities performed plenty of research works on GBNs synthesis and biological acitivity evaluation, but  there is limited comprehensive reviews published so far biological applications. So, we have studied a large number of scientific reports and investigations, presented in this review describing recent progress and modern perspectives with respect to graphene and related nanomaterials for biological applications.

Synthesis Design of TiO2 Nanotubes and Nanowires and Photocatalytic Applications in the Degradation of Organic Pollutants in the Presence or not of Microorganisms

2012 ◽  
Vol 1442 ◽  
Author(s):  
Asma Turki ◽  
Pilar Fernández Ibáñez ◽  
Abdelhamid Ghorbel ◽  
Hafedh Kochkar ◽  
Chantal Guillard ◽  
...  
Keyword(s):  
Formic Acid ◽  
Surface Area ◽  
Tio2 Nanotubes ◽  
High Surface ◽  
High Surface Area ◽  
Alkaline Solutions ◽  
Synthesis Design ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
Photocatalytic Applications

ABSTRACT1 D TiO2 nanomaterials (nanotubes, nanowires) were synthesized through hydrothermal treatment of TiO2 powder (P25) in concentrated alkaline solutions (NaOH for nanotubes, KOH for nanowires) followed by calcination at varying temperatures between 400°C and 700°C. Samples were characterized by HRTEM, XRD, Raman spectroscopy, and N2 adsorption-desorption isotherms. High surface area nanotubular TiO2 materials can maintain their 1D morphology up to a temperature of calcination of 400°C while changing their phase from hydrogenotitanate to anatase. The use of KOH leads to a retarded formation of anatase. Photocatalytic results showed that TiO2 anatase nanotubes calcined at 400°C can degrade formic acid with a rate constant four times higher than for P25. A direct correlation between surface area and photocatalytic activity explains the much higher activity of TiO2 anatase nanotubes. On the opposite, for the degradation of phenol, P25 remains more active. In the disinfection of water, contrary to P25, the high surface area of TiO2 nanotubes allows the simultaneous degradation of formic acid and the inactivation of pathogen fungus showing the interest of such materials for the treatment of wastewater.

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

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