Faculty Publications
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Item Graphene-mediated band gap engineering of WO3 nanoparticle and a relook at Tauc equation for band gap evaluation(Springer Verlag service@springer.de, 2018) Baishya, K.; Ray, J.S.; Dutta, P.; Das, P.P.; Das, S.K.Engineering the band gap of semiconductors is often crucial in the quest for developing new and advanced technologies. In this report, the implication of graphene on the band gap optimization of tungsten trioxide (WO3) is discussed. Simple one-step sol–gel process was followed to anchor WO3 nanoparticles in graphene. Graphene induces a redshift in the band gap of WO3. Band gap narrowing of 6.60% is observed for 7 wt% graphene-tethered WO3. Interestingly, a profound difference is observed in estimating the band gap energy values following the usual Tauc equation. Our observation suggests that the differential form of Tauc equation is better suited to determine the band gap energy of inorganic semiconductors than the typical extrapolation method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.Item Synthesis and characterization of titanium dioxide hollow nanofiber for photocatalytic degradation of methylene blue dye(MDPI AG, 2021) Jafri, N.N.M.; Jaafar, J.; Alias, N.H.; Samitsu, S.; Aziz, F.; Salleh, W.N.W.; Mohd Yusop, M.Z.M.; Othman, M.H.D.; Rahman, M.A.; A.F., A.F.; Matsuura, T.; Isloor, A.M.Environmental crisis and water contamination have led to worldwide exploration for advanced technologies for wastewater treatment, and one of them is photocatalytic degradation. A one?dimensional hollow nanofiber with enhanced photocatalytic properties is considered a promising material to be applied in the field. Therefore, we synthesized titanium dioxide hollow nanofibers (THNF) with extended surface area, light?harvesting properties and an anatase–rutile heterojunction via a template synthesis method and followed by a calcination process. The effect of calcination temperature on the formation and properties of THNF were determined and the possible mechanism of THNF formation was proposed. THNF nanofibers produced at 600 °C consisted of a mixture of 24.2% anatase and 75.8% rutile, with a specific surface area of 81.2776 m2/g. The hollow nanofibers also outperformed the other catalysts in terms of photocatalytic degradation of MB dye, at 85.5%. The optimum catalyst loading, dye concentration, pH, and H2O2 concentration were determined at 0.75 g/L, 10 ppm, pH 11, and 10 mM, respectively. The highest degradation of methylene blue dye achieved was 95.2% after 4 h of UV irradiation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.