scholarly journals Heterogenous Nanocomposite Catalysts With Rhenium Nanostructures for the Catalytic Reduction of 4-nitrophenol

2021 ◽  
Author(s):  
Piotr Cyganowski ◽  
Anna Dzimitrowicz
Keyword(s):  
Catalytic Activity ◽  
Catalytic Reduction ◽  
Reduction Process ◽  
Catalytic Decomposition ◽  
Primary Role ◽  
Polymeric Nanocomposites ◽  
Ir Transmission ◽  
Nanocomposite Catalysts ◽  
Efficient Loading ◽  
Catalytic Cycles

Abstract Stable and efficient heterogenous nanocatalysts for the reduction of 4-nitrophenol (4-NP) has attracted much attention in recent years. In this context, a unique and efficient in-situ approach is used for the production of new polymeric nanocomposites (pNCs) containing rhenium nanostructures (ReNSs). These rare materials should facilitate the catalytic decomposition of 4-NP, in turn ensuring increased catalytic activity and stability. These nanomaterials were analyzed using Fourier-Transformation Infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and X-Ray powder diffraction (XRD). The efficiency of the catalytic reaction was estimated based on the acquired UV-Vis spectra, which enabled the estimation of the catalytic activity using pseud-first order modelling. The applied method resulted in the successful production and efficient loading of ReNSs in the polymeric matrices. Amino functionalities played a primary role in the reduction process. Moreover, the functionality that is derived from 1.1’-carbonyl imidazole improved the availability of the ReNSs, which resulted in 90% conversion of 4-NP with a maximum rate constant of 0.28 min-1 over 11 subsequent catalytic cycles. This effect was observed despite the trace amount of Re in the pNCs (~5%), suggesting a synergistic effect between the polymeric base and the ReNSs-based catalyst.

Microstructure of Porous V2O-CeO2-SiO2 Catalyst for SCR of NO with NH3 at Low Temperature

2014 ◽  
Vol 875-877 ◽  
pp. 213-217 ◽  
Author(s):  
Mohd Razali Sohot ◽  
Umi Sarah Jais ◽  
Muhd Rosli Sulaiman
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
Reduction Process ◽  
No Emission ◽  
Scr Of No ◽  
Before And After ◽  
The Right ◽  
Proven Method

Selective catalytic reduction (SCR) is a well-proven method to reduce NO emission. However, to choose the right catalyst that provides a surface for reaction between NO and ammonia at low temperatures is a challenging task for a catalysts developers. In an earlier study, we prepared V2O5-CeO2-SiO2 catalyst with increasing V2O5 content by sol-gel route and found that the catalytic activity improved with increasing the V2O5 loading up to 0.5%. The catalytic activity, however, dropped when V2O5 loading was about 1% and increased back when the loading of V2O5 was about 5%. In this study, we looked into the microstructural relationship to explain these findings. The microstructures of the catalysts before and after exposure to NO gas revealed that the catalysts with 0.2% and 0.5% V2O5 were more porous after the reduction process possibly due to improved breakdown of (NH4)HCO3 to NH3 by the possible interaction with the V2O5 and CeO2-containing catalysts which consequently resulted in a more efficient NO reduction to N2 and H2O at low temperature. The microstructure of the catalyst with 1% V2O5 content to 5%, improved back the efficiency although clogging by CeVO4 phase still possible due to its presence based on XRD. The well-ordered micropores before exposure to NO and the more efficient breakdown of (NH4)HCO3 could have contributed to increase back the catalytic activity at low temperature.

Effect of precipitants on the catalytic activity of Co–Ce composite oxide for N2O catalytic decomposition

2017 ◽  
Vol 123 (2) ◽  
pp. 707-721 ◽  
Author(s):  
Yongzhao Wang ◽  
Xiaobo Hu ◽  
Ke Zheng ◽  
Hongxi Zhang ◽  
Yongxiang Zhao
Keyword(s):  
Catalytic Activity ◽  
Catalytic Decomposition ◽  
Composite Oxide

Application of S2O82-/FexOy Solid Super Acid as a Heterogeneous Fenton-Like Catalyst for the Degradation of Orange IV in Water

2010 ◽  
Vol 150-151 ◽  
pp. 1710-1713
Author(s):  
Ying Jie Zhang ◽  
Yue Xiao Tian ◽  
Da Peng Li ◽  
Guo Rui Liu ◽  
Li Zhang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Iron Oxides ◽  
Catalytic Decomposition ◽  
Optimal Conditions ◽  
Heterogeneous Fenton ◽  
Effective Catalyst ◽  
Preparation Conditions ◽  
Super Acid ◽  
Decomposition Of H2o2

A new Fenton-like catalyst was prepared to degrade Orange IV in water by catalytic decomposition of H2O2. The optimal preparation conditions were discussed. The catalytic activity of catalyst was evaluated by the degradation of Orange IV and the decomposition of H2O2. The results show that solid super acid (S2O82-/FexOy) soaked in (NH4)2S2O8 is the most effective catalyst among the synthesized iron oxides soaked in other oxidants. The optimal conditions for solid super acid preparation are calcined at 500 for 2 h in the air.

scholarly journals A Review on the Catalytic Hydrogenation of Bromate in Water Phase

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 365
Author(s):  
Jose Luis Cerrillo ◽  
Antonio Eduardo Palomares
Keyword(s):  
Catalytic Activity ◽  
Ion Exchange ◽  
Reaction Mechanisms ◽  
Catalytic Reduction ◽  
Environmental Concern ◽  
Chemical Reduction ◽  
Catalyst Stability ◽  
Polluted Water ◽  
Water Composition

The presence of bromate in water sources generates environmental concern due to its toxicity for humans. Diverse technologies, like membranes, ion exchange, chemical reduction, etc., can be employed to treat bromate-polluted water but they produce waste that must be treated. An alternative to these technologies can be the catalytic reduction of bromate to bromide using hydrogen as a reducing agent. In this review, we analyze the research published about this catalytic technology. Specifically, we summarize and discuss about the state of knowledge related to (1) the different metals used as catalysts for the reaction; (2) the influence of the support on the catalytic activity; (3) the characterization of the catalysts; (4) the reaction mechanisms; and (5) the influence of the water composition in the catalytic activity and in the catalyst stability. Based on published papers, we analyze the strength and weaknesses of this technique and the possibilities of using this reaction for the treatment of bromate-polluted water as a sustainable process.

A Critical Review of the Biological Processes in the Chemical Absorption-biological Reduction Integrated System for NO Removal

2021 ◽  
Vol 07 ◽  
Author(s):  
Wei Li
Keyword(s):  
Catalytic Reduction ◽  
Low Cost ◽  
Reduction Process ◽  
Integrated System ◽  
Future Research ◽  
Small Scale ◽  
Biological Processes ◽  
Chemical Absorption ◽  
Biological Reduction ◽  
Biological Reaction

: Exploring low-cost, green and safe technologies to provide an alternative to the conventional selective catalytic reduction process is key to the control of NOx emitted from small-scale boilers and other industrial processes. To meet the demand, the chemical absorption-biological reduction integrated system has been developing recently. chemical absorption-biological reduction integrated system applies Fe(II)EDTA for NO absorption and iron-reducing and denitrifying bacteria for absorbent regeneration. Many studies have focused on the enhancements of mass transfer and biological reaction, among which the biological processes were the rate-limiting steps. This review summarizes the current researches on the biological processes in the CABR system, which focuses on the mechanism and enhancement of biochemical reactions, and provides the possible directions of future research.

Au-on-Ag nanostructure for in-situ SERS monitoring of catalytic reactions

2022 ◽  
Author(s):  
Shuyue He ◽  
Di Wu ◽  
Siwei Chen ◽  
Kai Liu ◽  
Eui-Hyeok Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Thermal Evaporation ◽  
Reduction Process ◽  
Ag Nps ◽  
Au Nps ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Raman Probe

Abstract Dual-functionality Au-on-Ag nanostructures (AOA) were fabricated on a silicon substrate by first immobilizing citrate-reduced Ag nanoparticles (Ag NPs, ~43 nm in diameter), followed by depositing ~7 nm Au nanofilms (Au NFs) via thermal evaporation. Au NFs were introduced for their catalytic activity in concave-convex nano-configuration. Ag NPs underneath were used for their significant enhancement factor (EF) in surface-enhanced Raman scattering (SERS)-based measurements of analytes of interest. Rhodamine 6G (R6G) was utilized as the Raman-probe to evaluate the SERS sensitivity of AOA. The SERS EF of AOA is ~37 times than that of Au NPs. Using reduction of 4-nitrothiophenol (4-NTP) by sodium borohydride (NaBH4) as a model reaction, we demonstrated the robust catalytic activity of AOA as well as its capacity to continuously monitor via SERS the disappearance of reactant 4-NTP, emergence and disappearance of intermediate 4, 4’-DMAB, and the appearance of product 4-ATP throughout the reduction process in real-time and in situ.

Catalytic Reduction Performance of Carboxylated Alginic Acid Derivatives

2021 ◽  
Author(s):  
Raed H. Althomali ◽  
Khalid A. Alamry ◽  
Mahmoud Hussein Abdo ◽  
Shams H. Abdel-Hafez
Keyword(s):  
Metal Complexes ◽  
Metal Ion ◽  
Alginic Acid ◽  
Catalytic Reduction ◽  
Organic Dyes ◽  
Reduction Process ◽  
Spectroscopic Techniques ◽  
Reduction Behavior ◽  
Long Time ◽  
Ft Ir

Abstract In this study, the catalytic reduction behavior of carboxylated alginic acid derivatives has been investigated against the harmful organic dyes including Methyl Orange (MO) and Congo Red (CR). Alginic acid was firstly oxidized through an easy addition of KMnO4 as an oxidizing agent. A carboxylated alginic acid (CAA) has been interacted with selected metal ions (Sn, Fe, Ni, and Zr) through coordination bonds at the value of pH = 4 to form the corresponding metal complexes namely: Sn-CAA, Fe-CAA, Ni-CAA and Zr-CAA. The consistency of the coordination was confirmed by several spectroscopic techniques including FT-IR, XRD, SEM, and EDX. The catalytic reduction of these metal ion-based products was carried out against MO and CR in the presence of NaBH4 as a reducing agent under UV irradiation. All catalysts based metal complexes showed enhanced catalytic reduction against CR compared to MO. Among all those mentioned metal complexes Sn-CAA showed the best catalytic reduction of these dyes. The time taken by the Sn-CAA for CR, and MO is 5 and 7min respectively. Ni-CAA was classified as the second efficient product against both dyes, where the reduction process took 20 and 9 min respectively. The other two catalysts took a long time for CR and MO reduction. Zr-CAA showed more than 80 % reduction of only CR dye within 20 min. Whereas, Fe-CAA did not show any significant sign of reduction against both the dyes after the same time. The order of higher catalytic reduction was illustrated as: Sn-CAA > Ni-CAA > Zr-CAA = Fe-CAA.

Magnetic Pd/Fe3O4 Composite: Synthesis, Structure, and Catalytic Activity

2014 ◽  
Vol 67 (10) ◽  
pp. 1387 ◽  
Author(s):  
Shi-Qiang Bai ◽  
Lu Jiang ◽  
Sheng-Li Huang ◽  
Ming Lin ◽  
Shuang-Yuan Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Reduction Process ◽  
Pd Nanoparticles ◽  
Pincer Ligands ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Transmission Electron

Composite Pd/Fe3O4 (1) was designed and synthesised by immobilization of tridentate pincer ligands with triethoxysilane groups on Fe3O4 nanoparticles, PdII complexation, and in-situ reduction process. The composite was characterised by transmission electron microscopy, scanning electron microscopy energy-dispersive X-ray spectroscopy, powder X-ray diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Brunauer–Emmett–Teller analysis. The composite featured Pd nanoparticles of ~2–4 nm, exhibited good thermal stability and hydrophilic property as well as excellent catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol in water.

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