High catalytic activity of magnetic FeO /NiO /SBA-15: The role of Ni in the bimetallic oxides at the nanometer level

2015 ◽  
Vol 179 ◽  
pp. 239-248 ◽  
Author(s):  
Xingfa Li ◽  
Wanpeng Liu ◽  
Jianqing Ma ◽  
Yuezhong Wen ◽  
Zucheng Wu
Keyword(s):  
Catalytic Activity ◽  
High Catalytic Activity ◽  
Bimetallic Oxides

Role of microporous Janus silica nanosheets in the assembly of ultra-small Ag nanoparticles with high catalytic activity

2021 ◽  
Vol 50 (1) ◽  
pp. 208-216
Author(s):  
Mengnan Yang ◽  
Zhaoli Yan ◽  
Tiantian Li ◽  
Bing Liu ◽  
Qiangshan Jing ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Ag Nanoparticles ◽  
High Catalytic Activity ◽  
Charged Surface ◽  
Highly Efficient ◽  
Surface Hydroxyls

Negatively charged surface hydroxyls and micropores of Janus silica nanosheets play a particular role in the highly efficient and dispersed assembly of ultra-small Ag nanoparticles with high catalytic activity.

LDH-derived catalysts for complete oxidation of volatile organic compounds

Clay Minerals ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 67-77 ◽  
Author(s):  
K. Bahranowski ◽  
E. Bielańska ◽  
R. Janik ◽  
T. Machej ◽  
E. M. Serwicka
Keyword(s):  
Catalytic Activity ◽  
Mixed Oxide ◽  
Copper Chromite ◽  
Oxide System ◽  
High Catalytic Activity ◽  
Commercial Catalyst ◽  
Volatile Organic ◽  
Double Hydroxides ◽  
Very High

AbstractThe Cu,Cr-, Zn,Cr- and Cu,Al-layered double hydroxides have been synthesized by the coprecipitation method and characterized by elemental analysis, PXRD, SEM/EDS and BET. The mixed oxide materials obtained upon calcination at 873 K show very high catalytic activity for the combustion of toluene and ethanol. The best sample is derived from the Cu,Cr-LDH precursor with a Cu:Cr ratio of 2, composed of copper oxide and copper chromite. This catalyst gave 50% conversion of toluene and ethanol at temperatures of 45 and 15 K lower, respectively, than the reference commercial catalyst. Catalytic tests with a mechanical mixture of CuO and CuCr2O4 demonstrate that the use of an LDH precursor is essential for optimum results. The importance of the simultaneous presence of both Cu and Cr, the influence of the Cu:Cr ratio on the catalytic activity and the role of the interface boundaries in the CuO-CuCr2O4 mixed oxide system are discussed.

Chitosan Based Nanocomposite Materials as Photocatalyst – A Review

2014 ◽  
Vol 781 ◽  
pp. 79-94 ◽  
Author(s):  
A. Nithya ◽  
Kandasamy Jothivenkatachalam ◽  
S. Prabhu ◽  
K. Jeganathan
Keyword(s):  
Catalytic Activity ◽  
Environmental Remediation ◽  
Low Cost ◽  
Nanocomposite Materials ◽  
Heterogeneous Photocatalysis ◽  
Organic Polymer ◽  
High Catalytic Activity ◽  
Environmental Application ◽  
Industrial Activities

Heterogeneous photocatalysis is a significant technology for environmental application. Moreover, immobilising an appropriate catalyst on the surface of a natural organic polymer presents a number of additional advantages including low-cost, high catalytic activity and extensive potential reuse for the application of pharmaceutical, biomedical and industrial activities. This review mainly focuses on the role of chitosan based material as photocatalyst on the environmental remediation.

scholarly journals Microbial Phosphotriesterase: Structure, Function, and Biotechnological Applications

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 671 ◽  
Author(s):  
Wahhida Latip ◽  
Victor Feizal Knight ◽  
Norhana Abdul Halim ◽  
Keat Khim Ong ◽  
Noor Azilah Mohd Kassim ◽  
...  
Keyword(s):  
Nervous System ◽  
Catalytic Activity ◽  
Active Site ◽  
Soil Bacteria ◽  
Environmental Issues ◽  
High Catalytic Activity ◽  
Biotechnological Applications ◽  
Microbial Enzymes ◽  
Toxicity Effects

The role of phosphotriesterase as an enzyme which is able to hydrolyze organophosphate compounds cannot be disputed. Contamination by organophosphate (OP) compounds in the environment is alarming, and even more worrying is the toxicity of this compound, which affects the nervous system. Thus, it is important to find a safer way to detoxify, detect and recuperate from the toxicity effects of this compound. Phosphotriesterases (PTEs) are mostly isolated from soil bacteria and are classified as metalloenzymes or metal-dependent enzymes that contain bimetals at the active site. There are three separate pockets to accommodate the substrate into the active site of each PTE. This enzyme generally shows a high catalytic activity towards phosphotriesters. These microbial enzymes are robust and easy to manipulate. Currently, PTEs are widely studied for the detection, detoxification, and enzyme therapies for OP compound poisoning incidents. The discovery and understanding of PTEs would pave ways for greener approaches in biotechnological applications and to solve environmental issues relating to OP contamination.

Mechanistic insights into the photocatalytic properties of metal nanocluster/graphene ensembles. Examining the role of visible light in the reduction of 4-nitrophenol

Nanoscale ◽  
2017 ◽  
Vol 9 (27) ◽  
pp. 9685-9692 ◽  
Author(s):  
Malamatenia A. Koklioti ◽  
Theodosis Skaltsas ◽  
Yuta Sato ◽  
Kazu Suenaga ◽  
Anastasios Stergiou ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Visible Light ◽  
Photocatalytic Properties ◽  
High Catalytic Activity ◽  
Metal Nanocluster

The high catalytic activity of AuNCs/f-G for the reduction of 4-nitrophenol under visible light is ascribed to three synergistic mechanisms.

Thioacetalization of aldehydes and ketones in the presence of hydroxo complexes of platinum(II): An example of Lewis acid catalytic activity

2001 ◽  
Vol 79 (5-6) ◽  
pp. 621-625 ◽  
Author(s):  
Lorenzo Battaglia ◽  
Francesco Pinna ◽  
Giorgio Strukul
Keyword(s):  
Catalytic Activity ◽  
Lewis Acid ◽  
Reaction Rate ◽  
Platinum Complex ◽  
Acid Catalyst ◽  
High Catalytic Activity ◽  
Hydroxo Complexes ◽  
Aldehydes And Ketones ◽  
Lewis Acid Catalyst

The complex [(dppb)Pt(µ-OH)]2(BF4)2 displays high catalytic activity in the thioacetalization of a variety of aldehydes and ketones with mercaptoethanol under very mild conditions. The reaction rate is greatly enhanced by the addition to the reaction mixture of magnesium perchlorate as drying agent and molar turnovers as high as 9700 can be observed. The effect of different desiccating agents is also reported. The reactivity pattern observed, the similarity with other reactions and NMR spectroscopic investigations confirm the possible role of the complex as Lewis acid catalyst in promoting the reaction.Key words: thioacetalization, catalysis, aldehydes, ketones, platinum complex.

Creation of cross directing intergrowth MOR/ZSM-5 with high catalytic activity: Insights into the role of crystallization time

2021 ◽  
Vol 320 ◽  
pp. 111102
Author(s):  
Zhe Hong ◽  
Junhui Li ◽  
Chuanfang Xiong ◽  
Guoqing Zhao ◽  
Xiaoxia Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Crystallization Time ◽  
High Catalytic Activity

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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