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Enhanced visible light photocatalytic activity of Gd‐doped CeO 2 nanoparticles (NPs) is experimentally demonstrated, whereas there are very few reports on this mechanism with rare earth doping. All‐pure and Gd‐doped CeO 2 NPs are synthesized using a coprecipitation method and characterized using X‐ray diffraction (XRD), absorption spectroscopy, surface‐enhanced Raman Spectroscopy (SERS), X‐ray photoelectron spectroscopy (XPS), and superconducting quantum interference device (SQUID). The effect of Gd‐doping on properties of CeO 2 is discussed along with defects and oxygen vacancies generation. The XRD confirms the incorporation of Gd 3+ at the Ce 3+ /Ce 4+ site by keeping the crystal structure same. The average particle size from transmission electron microscopy (TEM) images is in the range of 5–7 nm. The XPS spectra of Ce 3d, O 1s, and Gd 4d exhibits the formation of oxygen vacancies to maintain the charge neutrality when Ce 4+ changes to Ce 3+ . The gradual increase in hydrogen production is observed with increasing Gd concentration. The observed results are in good correlation with the characterization results and a mechanism of water splitting is proposed on the basis of analyses. The absorption spectra reveal optical band gap (2.5–2.7 eV) of samples, showing band gap narrowing leads to desired optical absorbance and photoactivity of NPs.

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Motivated by the outstanding properties and unique structure of graphene oxide (GO), the polymer nanocomposites of ethyl cellulose (EC) as a polymer matrix and the GO as a nano‐filler have been prepared with the different GO wt% concentrations using simple solution blending technique followed by the ultrasonication treatment and characterized by using various advanced techniques. The X‐ray diffraction (XRD) was utilized to determine the preliminary phase determination and for the structural analysis. The optical band gaps were determined with the help of UV‐Vis‐NIR spectrophotometer and were verified by the PL spectra using Spectro‐Fluorescence. According to experimental results, the optical bandgap of the nanocomposite was found to reduce with increasing GO content. The field emission scanning electron microscopy (FESEM) was used to study the surface morphology and to identify the presence of GO in the nanocomposites. The Fourier transform infrared (FTIR) study has been carried out to recognize the presence of functional groups and their vibrational mechanisms. Micro‐Raman imaging technique has been used to determine the Raman bands present in the nanocomposites. The optical band gap of the nanocomposites reflects the semiconducting nature, which might be used in optoelectronic devices and sensor applications.