Palladium nanoparticles decorated on reduced graphene oxide: An efficient catalyst for ligand- and copper-free Sonogashira reaction at room temperature

2017 ◽  
Vol 31 (8) ◽  
pp. e3679 ◽  
Author(s):  
Abhijit Mahanta ◽  
Najrul Hussain ◽  
Manash R. Das ◽  
Ashim J. Thakur ◽  
Utpal Bora
NANO ◽  
2018 ◽  
Vol 13 (09) ◽  
pp. 1850101 ◽  
Author(s):  
Hao Yan ◽  
Mengru Xue ◽  
Xiangqing Li ◽  
Lixia Qin ◽  
Shi-Zhao Kang

An efficient and stable catalyst was prepared utilizing reduced graphene oxide, Ag nanoparticles and melamine sponge for the restoration of large volume effluent containing 4-nitrophenol at room temperature. And the as-prepared sample is suitable for continuous flow system. Almost 99% 4-nitrophenol ([Formula: see text][Formula: see text]mol[Formula: see text]L[Formula: see text], 100[Formula: see text]mL) can be removed within 4[Formula: see text]min in the presence of the aforementioned sample. Moreover, it also exhibits remarkable stability in continuous flow system. This may offer a new route to the fabrication of efficient flowing catalytic system.


Author(s):  
Junyu Chang ◽  
Xiaobo Zhang ◽  
Zhenming Wang ◽  
Chunsheng Li ◽  
Qi Hu ◽  
...  

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 134
Author(s):  
Koduru Mallikarjuna ◽  
Lebaka Veeranjaneya Reddy ◽  
Sarah Al-Rasheed ◽  
Arifullah Mohammed ◽  
Sreedevi Gedi ◽  
...  

Novel reduced graphene oxide-supported palladium nanoparticles (RGO-PN) were synthesized under ultrasonication, a method that utilizes Coleus amboinicus as a bio-reduction agent. Green synthesized RGO-PN nanoparticles with a crystallite size in the range of 40–50 nm were confirmed in X-ray diffraction (XRD) spectra. RGO-PN show an absorption peak at 220 nm while reduced graphene oxide (RGO) shows its maximal absorbance at 210 nm. The scanning electron microscope image revealed that 40-nm-sized spherical-shaped palladium nanoparticles stick well to reduced graphene oxide sheets, which is consistent and correlated well with the XRD pattern. Moreover, a high-resolution morphological image of RGO-PN100 was obtained by TEM analysis, which shows the anchoring of palladium nanoparticles (PN) on RGO nanosheets. Green synthesized RGO-PN100 nanoparticles from Coleus amboinicus show better reduction kinetics for 4-nitrophenol at 40 min, suggesting that RGO-PN prepared from Coleus amboinicus serve as an excellent catalytic reducing agent. Furthermore, they show remarkable antibacterial activity against Escherichia coli (ATCC 25922). Thus, green synthesized RGO-supported palladium nanoparticles demonstrated that enhanced catalytic activity and antibacterial activity both play an important role in the environmental and medical disciplines.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 623
Author(s):  
Monika Gupta ◽  
Huzein Fahmi Hawari ◽  
Pradeep Kumar ◽  
Zainal Arif Burhanudin ◽  
Nelson Tansu

The demand for carbon dioxide (CO2) gas detection is increasing nowadays. However, its fast detection at room temperature (RT) is a major challenge. Graphene is found to be the most promising sensing material for RT detection, owing to its high surface area and electrical conductivity. In this work, we report a highly edge functionalized chemically synthesized reduced graphene oxide (rGO) thin films to achieve fast sensing response for CO2 gas at room temperature. The high amount of edge functional groups is prominent for the sorption of CO2 molecules. Initially, rGO is synthesized by reduction of GO using ascorbic acid (AA) as a reducing agent. Three different concentrations of rGO are prepared using three AA concentrations (25, 50, and 100 mg) to optimize the material properties such as functional groups and conductivity. Thin films of three different AA reduced rGO suspensions (AArGO25, AArGO50, AArGO100) are developed and later analyzed using standard FTIR, XRD, Raman, XPS, TEM, SEM, and four-point probe measurement techniques. We find that the highest edge functionality is achieved by the AArGO25 sample with a conductivity of ~1389 S/cm. The functionalized AArGO25 gas sensor shows recordable high sensing properties (response and recovery time) with good repeatability for CO2 at room temperature at 500 ppm and 50 ppm. Short response and recovery time of ~26 s and ~10 s, respectively, are achieved for 500 ppm CO2 gas with the sensitivity of ~50 Hz/µg. We believe that a highly functionalized AArGO CO2 gas sensor could be applicable for enhanced oil recovery, industrial and domestic safety applications.


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