Positively Charged Gold Nanoparticles for Hydrogen Peroxide Detection

https://link.springer.com/article/10.1007/s12668-018-0503-x

Positively Charged Gold Nanoparticles for Hydrogen Peroxide Detection

https://link.springer.com/article/10.1007/s12668-018-0503-x

Environmentally Sustainable Fabrication of Ag@g-C₃N₄ Nanostructures and Their Multifunctional Efficacy as Antibacterial Agents and Photocatalysts

https://pubs.acs.org/doi/abs/10.1021/acsanm.8b00548?mi=aayia761&af=R&AllField=nano&target=default&targetTab=std

Environmentally Sustainable Fabrication of Ag@g-C₃N₄ Nanostructures and Their Multifunctional Efficacy as Antibacterial Agents and Photocatalysts

https://pubs.acs.org/doi/abs/10.1021/acsanm.8b00548?mi=aayia761&af=R&AllField=nano&target=default&targetTab=std

Environmentally sustainable biogenic fabrication of AuNP decorated-graphitic g-C₃N₄ nanostructures towards improved photoelectrochemical performances

http://pubs.rsc.org/en/content/articlelanding/2018/ra/c8ra00690c#!divAbstract 

Recent progress of metal–graphene nanostructures in photocatalysis

http://pubs.rsc.org/en/content/articlelanding/2018/nr/c8nr03500h#!divAbstract 

A special issue in Frontiers in Chemistry on "Graphene-Based Nanocomposites for Photocatalysis " is open for submission. Please find details in the web page.

https://www.frontiersin.org/research-topics/7676/graphene-based-nanocomposites-for-photocatalysis ;

Design and development of highly active and durable oxygen reduction reaction (ORR) catalyst to replace Pt- and Pt-based materials are the present challenges in fuel cell research including direct methanol fuel cells (DMFC). The methanol crossover and oxidation at cathode is another unwanted issue that reduces the efficiency of DMFC. Herein we report cobalt-doped ceria (Co-CeO2) as a promising electrocatalyst with competent ORR kinetics mainly through a four electron reduction pathway and it surpasses Pt/C by a great margin in terms of stability and methanol tolerance. The Co-CeO2 nanoparticles of diameter 4-7 nm were uniformly grown on reduced graphene oxide (rGO) by a facile single-step hydrothermal process. The as-synthesized Co-CeO2nanoparticles/rGO nanocomposites are further demonstrated as an active energy storage material in supercapacitor underlying the importance of the studied material in renewable energy industries.

http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b06846

Cerium oxide nanoparticles (CeO2 NPs) were fabricated and grown on graphene sheets using a facile, low cost hydrothermal approach and subsequently characterized using different standard characterization techniques. X-ray photoelectron spectroscopy and electron paramagnetic resonance revealed the changes in surface states, composition, changes in Ce4+ to Ce3+ ratio, and other defects. Transmission electron microscopy (TEM) and high resolution TEM revealed that the fabricated CeO2 NPs to be spherical with particle size of ~10–12 nm. Combination of defects in CeO2 NPs with optimal amount of two-dimensional graphene sheets had a significant effect on the properties of the resulting hybrid CeO2-Graphene nanostructures, such as improved optical, photocatalytic, and photocapacitive performance. The excellent photocatalytic degradation performances were examined by monitoring their ability to degrade Congo red ~94.5% and methylene blue dye ~98% under visible light irradiation. The photoelectrode performance had a maximum photocapacitance of 177.54 Fg−1 and exhibited regular capacitive behavior. Therefore, the Ce3+-ion, surface-oxygen-vacancies, and defects-induced behavior can be attributed to the suppression of the recombination of photo-generated electron–hole pairs due to the rapid charge transfer between the CeO2 NPs and graphene sheets. These findings will have a profound effect on the use of CeO2-Graphene nanostructures for future energy and environment-related applications. 

https://www.nature.com/articles/s41598-017-06139-6

This paper reports cadmium sulphide nanoparticles-(CdS NPs)-graphene nanocomposite (CdS-Graphene), prepared by a simple method, in which CdS NPs were anchored/decorated successfully onto graphene sheets. The as-synthesized nanocomposite was characterized using standard characterization techniques. A combination of CdS NPs with the optimal amount of two-dimensional graphene sheets had a profound influence on the properties of the resulting hybrid nanocomposite, such as enhanced optical, photocatalytic, and photo-electronic properties. The photocatalytic degradation ability of the CdS-Graphene nanocomposite was evaluated by degrading different types of dyes in the dark and under visible light irradiation. Furthermore, the photoelectrode performance of the nanocomposite was evaluated by different electrochemical techniques. The results showed that the CdS-Graphene nanocomposite can serve as an efficient visible-light-driven photocatalyst as well as photoelectrochemical performance for optoelectronic applications. The significantly enhanced photocatalytic and photoelectrochemical performance of the CdS-Graphene nanocomposite was attributed to the synergistic effects of the enhanced light absorption behaviour and high electron conductivity of the CdS NPs and graphene sheets, which facilitates charge separation and lengthens the lifetime of photogenerated electron–hole pairs by reducing the recombination rate. The as-synthesized narrow band gap CdS-Graphene nanocomposite can be used for wide range of visible light-induced photocatalytic and photoelectrochemical based applications.http://www.sciencedirect.com/science/article/pii/S0021979716305379

In this study, pure ZnO, CeO2 and ZnO/CeO2 nanocomposites were synthesized using a thermal decomposition method and subsequently characterizhttp://www.nature.com/articles/srep31641ed using different standard techniques. High-resolution X-ray photoelectron spectroscopy measurements confirmed the oxidation states and presence of Zn2+, Ce4+, Ce3+ and different bonded oxygen species in the nanocomposites. The prepared pure ZnO and CeO2 as well as the ZnO/CeO2nanocomposites with various proportions of ZnO and CeO2 were tested for photocatalytic degradation of methyl orange, methylene blue and phenol under visible-light irradiation. The optimized and highly efficient ZnO/CeO2 (90:10) nanocomposite exhibited enhanced photocatalytic degradation performance for the degradation of methyl orange, methylene blue, and phenol as well as industrial textile effluent compared to ZnO, CeO2 and the other investigated nanocomposites. Moreover, the recycling results demonstrate that the ZnO/CeO2 (90:10) nanocomposite exhibited good stability and long-term durability. Furthermore, the prepared ZnO/CeO2 nanocomposites were used for the electrochemical detection of uric acid and ascorbic acid. The ZnO/CeO2 (90:10) nanocomposite also demonstrated the best detection, sensitivity and performance among the investigated materials in this application. These findings suggest that the synthesized ZnO/CeO2(90:10) nanocomposite could be effectively used in various applications.

This paper reports cadmium sulphide nanoparticles-(CdS NPs)-graphene nanocomposite (CdS-Graphene), prepared by a simple method, in which CdS NPs were anchored/decorated successfully onto graphene sheets. The as-synthesized nanocomposite was characterized using standard characterization techniques. A combination of CdS NPs with the optimal amount of two-dimensional graphene sheets had a profound influence on the properties of the resulting hybrid nanocomposite, such as enhanced optical, photocatalytic, and photo-electronic properties. The photocatalytic degradation ability of the CdS-Graphene nanocomposite was evaluated by degrading different types of dyes in the dark and under visible light irradiation. Furthermore, the photoelectrode performance of the nanocomposite was evaluated by different electrochemical techniques. The results showed that the CdS-Graphene nanocomposite can serve as an efficient visible-light-driven photocatalyst as well as photoelectrochemical performance for optoelectronic applications. The significantly enhanced photocatalytic and photoelectrochemical performance of the CdS-Graphene nanocomposite was attributed to the synergistic effects of the enhanced light absorption behaviour and high electron conductivity of the CdS NPs and graphene sheets, which facilitates charge separation and lengthens the lifetime of photogenerated electron–hole pairs by reducing the recombination rate. The as-synthesized narrow band gap CdS-Graphene nanocomposite can be used for wide range of visible light-induced photocatalytic and photoelectrochemical based applications.

In this study, pure ZnO, CeO2 and ZnO/CeO2 nanocomposites were synthesized using a thermal decomposition method and subsequently characterized using different standard techniques. High-resolution X-ray photoelectron spectroscopy measurements confirmed the oxidation states and presence of Zn2+, Ce4+, Ce3+ and different bonded oxygen species in the nanocomposites. The prepared pure ZnO and CeO2 as well as the ZnO/CeO2nanocomposites with various proportions of ZnO and CeO2 were tested for   degradation of methyl orange, methylene blue and phenol under visible-light irradiation. The optimized and highly efficient ZnO/CeO2 (90:10) nanocomposite exhibited enhanced photocatalytic degradation performance for the degradation of methyl orange, methylene blue, and phenol as well as industrial textile effluent compared to ZnO, CeO2 and the other investigated nanocomposites. Moreover, the recycling results demonstrate that the ZnO/CeO2 (90:10) nanocomposite exhibited good stability and long-term durability. Furthermore, the prepared ZnO/CeO2 nanocomposites were used for the electrochemical detection of uric acid and ascorbic acid. The ZnO/CeO2 (90:10) nanocomposite also demonstrated the best detection, sensitivity and performance among the investigated materials in this application. These findings suggest that the synthesized ZnO/CeO2(90:10) nanocomposite could be effectively used in various applications.

R. Saravanana, E. Sacari, F. Gracia, M. Mansoob Khan, E. Mosquera, V. K. Gupta, Conducting PANI stimulated ZnO system for visible light photocatalytic degradation of coloured dyes. Journal of Molecular Liquids 2016, 221, 1029–1033.

The hybridization of two different materials is important for achieving improved photocatalytic degradation properties. Generally, photocatalysts do not show good linear catalytic performance toward all the dyes. This paper reports the synthesis of nano-assembled TiO₂/BiOX (X = Cl, Br, or I) hybrid microspheres, which were confirmed by powder X-ray diffraction, field emission scanning electron microscopy, electron transmission microscopy, UV–visible spectroscopy, Fourier-transform infrared spectroscopy, and photoluminescence spectroscopy. The synthesized photocatalysts were examined extensively for their photocatalytic activities with single (orange G and tartrazine), mixed dyes (methyl orange + rhodamine B + methylene blue), natural dyes extracted from grapes and cabbages (real sample analysis) as well as a commercially available drink with and without H₂O₂ addition under visible light irradiation. For the mixed dyes, TiO₂/BiOI showed the highest adsorption capacity and TiO₂/BiOCl showed the highest photocatalytic activity. Methyl orange in the mixed dyes was the most rapidly photodegraded of all the photocatalysts examined. TiO₂/BiOI showed the highest photocatalytic activity for orange G and tartrazine. The three different photocatalysts showed effective and uniform degradation activity to the natural dyes obtained from grapes and cabbages. The dye degradation was enhanced by H₂O₂ addition.

http://www.sciencedirect.com/science/article/pii/S1383586616300090

Green synthesis, photocatalytic and photoelectrochemical performance of an Au–Graphene nanocomposite

DOI: 10.1039/C5RA01864A

http://pubs.rsc.org/en/content/articlelanding/2015/ra/c5ra01864a#!divAbstract

Biogenic synthesis of a Ag–graphene nanocomposite with efficient photocatalytic degradation, electrical conductivity and photoelectrochemical performance

DOI: 10.1039/C5NJ01320H

http://pubs.rsc.org/en/Content/ArticleLanding/2015/NJ/c5nj01320h#!divAbstract

Defect-Induced Band Gap Narrowed CeO2 Nanostructures for Visible Light Activities

Ind. Eng. Chem. Res. 2014, 53, 9754 −9763

http://pubs.acs.org/doi/pdf/10.1021/ie500986n

Abstract:

This work reports an electron beam irradiation (30 kGy and 90 kGy) approach to narrow the band gap of the pristine CeO2 nanostructure (p-CeO2) to enhance their visible light activity through defect engineering. This was confirmed by diffuse reflectance spectroscopy, photoluminescence, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Brunauer−Emmett −Teller, electrochemical impedance spectroscopy, and linear scan voltammetry. XPS revealed changes in the surface states, composition, Ce4+ to Ce3+ ratio, and other defects in the modified CeO2 nanostructures (m-CeO2). The mCeO 2 exhibits excellent photocatalytic activities by degrading 4-nitrophenol and methylene blue in the presence of visible light (λ > 400 nm) compared to the p-CeO2. The optical, photocatalytic, and photoelectrochemical studies and proposed mechanism
further support the enhanced visible light photocatalytic activities of the m-CeO2. This study confirmed that defect-induced band gap engineered m-CeO2 could be used effectively as photocatalyst and photoelectrodes owing to their enhanced visible light photocatalytic activities.