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The addition of reduced graphene oxide (rGO) into semiconducting metal oxide nanomaterials is a trending material that has been used in a wide range of applications to improve the efficiency of metal oxides. In this present work, we synthesize rGO/WO3 nanohybrids via a simple one-step hydrothermal route. During the hydrothermal treatment, the subsequent in situ reduction of GO into rGO occurred in Millipore water without using any surfactant or reducing agents. A high-resolution transmission electron microscope investigated the morphology of the prepared samples. The phase formation was confirmed by X-ray diffraction pattern and Raman spectroscopy. To assess the photocatalytic activity, prepared samples were used to suppress methylene blue (MB) dye under sunlight irradiation. From the results, the WR3 (i.e., WO3 + 30 mg GO) shows a higher catalytic activity for MB degradation. The constant rate values of WR3 (i.e., WO3 + 30 mg GO) also increased to ∼6.5 times compared to WO3. The enhanced catalytic activity of the prepared samples is due to the synergistic effect induced electron–hole recombination delay in the nanocomposites, which is confirmed from the photoluminescence spectroscopy. To probe the active species involved in photocatalysis, in situ scavenger studies were done. A two-route photocatalytic mechanism was proposed to explain the photocatalytic reaction.

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In the 21st century, climate change and global warming are considered to be one of the world’s most severe and biggest environmental threats to humans. Consequently, the CO2 capture and storage technique has been a concern as a superior technique by both industrial and academic research communities, which prohibits the mixing of CO2 from point sources, such as cement plants and fossil fuel power plants, into the atmosphere. Particularly, after the United Nations Climate Change Conference in 2015, which was held in Paris, France, researchers have been vigorously focusing on the reduction of greenhouse gases. Presently, liquid amine scrubbing has been used for CO2 capture technology, while solid sorbents are used for CO2 capture technology to overcome the drawbacks associated with amine scrubbing technology. In this review, different carbon nanomaterials, such as fullerene, carbon nanotubes, graphene oxide, biochar, and activated carbon, and their derivatives for CO2 capture applications are summarized. In addition, the review covers the fundamental requirements of solid sorbents, advantages and disadvantages of other solid sorbents, and policies proposed for reducing greenhouse gas emissions by developing and developed countries, which will be highly beneficial for making future policies and fabricating low-cost CO2 sorbents. Finally, the current technical challenges and opportunities for the development of efficient and practically possible carbon-based CO2 sorbents were discussed. Furthermore, future perspectives were proposed for the development of carbonaceous porous materials in place of existing liquid amine scrubbing technology in the future.

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Herein, we report the synthesis of reduced graphene oxide/molybdenum oxide (rGO/MoO3) via a simple precipitation method to improve the optical nonlinearity of MoO3. The successful materialization of composites was confirmed through x-ray diffraction, Raman spectroscopy, and field emission scanning electron microscopy studies. Rietveld refinement was done for the prepared samples to study the structural analysis. The optical studies revealed strong UV absorption and strong violet emission under 330 nm excitation. The mechanism of violet, blue, and green emissions from MoO3 is proposed through molybdenum interstitial related defects. The variation of bandgap in rGO/MoO3 composites was explained by the graphene induced strain on MoO3. The phonon lifetime of each sample was calculated, and it was found to decrease with respect to the rGO concentration, which makes this composite material potentially applicable for several electronic and optical applications. Moreover, energy dependent optical power limiting properties of the prepared MoO3 and rGO/MoO3 nanocomposites were measured by open aperture z-scan using nanosecond Nd-YAG pulsed laser operating at 532 nm excitation. It is found that the rGO/MoO3 nanocomposites have better optical power limiting properties with a good two photon absorption coefficient of 9.0 × 10−10 m/W. This could be attributed to the efficient interfacial charge transfer between MoO3 and rGO.

Three cyanostilbene derivatives bearing a triphenylamine donor and cyano receptor are synthesized and characterized. The molecules exhibited characteristics solvatochromism. The bromo‐derivatives able to sense the explosive picric acid selectively with an excellent naked eye detection limit of 1×10−11 M. Furthermore, the bromo‐derivative showed brilliant non‐linear optical properties.