Three MFCs with different catalyst incorporated on carbon felt cathode, viz. nickel phthalocyanine-MnOx (NiPc-MnOx) composite (MFC-1), platinum (MFC-2), control MFC with bare carbon felt (MFC-3) were used for treating distillery wastewater. The linear sweep voltammetry studies revealed that a maximum current density of 3.7 Am-2 was achieved for NiPc-MnOx/C catalysed cathode, which is 13-folds higher than that for control cathode (0.27 Am-2). Consequently, MFC-1 demonstrated a power density of 48.8 mWm-2, which was around 3.3-folds higher than the control MFC (14.9 mWm-2) owing to the improved oxidation reduction kinetics in case of NiPc-MnOx/C catalysed cathode. Coulombic efficiency (CE) was enhanced by a margin of about 11 % for MFC-1 (24.8 %) in comparison to MFC-3 (13.4 %). MFC-2 having platinum cathode catalyst exhibited a power density of 61.3 mWm-2, which was slightly higher than that achieved by MFC-2. However, NiPc-MnOx was prepared at 3-fold less cost as compared to platinum. Hence, NiPc-MnOx/C can be used as an alternative to platinum as cathode catalyst in MFC treating distillery wastewater.

In this experiment, a new bimetal low–cost Cu–Sn alloy was synthesized and it was tested as catalyst for oxygen reduction reaction (ORR) in MFC and the results were compared with the commercially available Pt-C catalyst. Cyclic voltammetry for evaluating ORR of the test cathode containing Cu-Sn catalysts under oxygen saturated environment displayed large ORR current peak, showing less overpotential demand for ORR. Maximum power density of 457 mW/m2 obtained from MFC using Cu–Sn catalyst, was found to be slightly higher than the power density of 446 mW/m2 demonstrated by MFC using Pt based cathode. Biochemical conversion of organic matter to direct electric current in Cu–Sn based MFC occurred at a coulombic efficiency of 55.8%, while demonstrating 92% of chemical oxygen demand removal. This study demonstrated application of low cost Cu–Sn bimetal alloy as excellent ORR catalyst in MFC and would be very helpful to commission larger MFCs for field applications to harvest energy in the form of direct electricity from wastewaters while offering wastewater treatment.

Density Functional Theory (DFT) calculations study of Cu doped {0001} and {01-12} surfaces of hematite for enhanced water splitting have been carried out. The doping was restricted to planes in the vicinity of the surface, specifically from the top most layers to the third inner layer of Fe atoms. Thermodynamic stabilities were evaluated based on surface energies and formation energies. The evaluation of thermodynamic stabilities (negative formation energy values) shows that the systems are thermodynamically stable which suggest that they can be synthesized in the laboratory under favorable conditions. Doping on the top most layer yields the energetically most favorable structure. The calculated charge density difference plots showed the concentration of charge mainly at the top of the surface (termination region), and this charge depleted from the Cu atom to the surrounding Fe and O atoms. This phenomenon (concentration of charge at the top of the surface) is likely to reduce the distance moved by the charge carriers, decrease in charge recombination leading to facile transfer of charge to the adsorbate and, suggesting improved photoelectrochemical water oxidation activity of hematite. The analysis of electron electronic structure reveals that Cu doped surface systems does not only decrease the band gap but also leads to the correct conduction band alignment for direct water splitting without external bias voltage.

Graphene and graphene oxide are being investigated for use in drug delivery systems, bioimaging, and antimicrobial applications. However, their effects, if any, on healthy cells need to be established before they can be deemed safe for therapeutic use. This research tested whether graphene oxide (GO) and/or partially reduced graphene oxide (pRGO) exhibit antimicrobial properties on Staphylococcus aureus; and also examined the growth and proliferation of dermal fibroblasts and keratinocytes in media modified with graphene oxide or partially reduced graphene oxide. Staphylococcus aureus was able to proliferate in both GO and pRGO- modified growth media as well as on gelatin made with GO and pRGO solutions. Both GO and pRGO increased dermal fibroblast doubling time and displayed lower cell counts compared to the control, with pRGO exerting a more pronounced effect than GO. After 4 days of keratinocyte incubation, GO and pRGO showed cell counts 75-80% less than the control. Cell counts of test samples dropped even lower by day 5 while the control cell count increased, suggesting that more investigation into the properties as well as the safety of graphene and its derivatives needs to be done before it is implemented for medical applications.

Tungsten oxide based micro and nanostructures as well as their 2-D integrated counterparts with appropriate surface modifications such as sensitization, coating of other semiconductors or growth of functional groups have been examined to enhance supercapacitance and sensing capabilities. With the goal of investigation of these changes, the electrochemical capacitance behavior of newly prepared nano and micro-structured tungsten oxide coated substrates were examined. The utilization of WO3 based sensors to differentiate edible colorant and toxic pigments, was also explored. The systematic electrochemical analysis and comparative study of selected colorants was done in order to establish a roadmap to detect model organic compounds for better preventive action.

Recently, photoelectrochemical (PEC) water splitting using semiconductor photoanode has received great attention due production of hydrogen through clean energy. The alpha hematite (α Fe2O3) is one of the candidate amongst photoanodic materials, which is chemically stable, abundant in nature with a band gap of 2.0-2. 2eV allowing to be harvesting in the visible light. However, it has also drawn back due to high recombination rate of electron–hole pair revealing the low concentration of charges and lower device performance. In common with α-Fe2O3, the titanium dioxide (TiO2) has been known as one of the most explored photoanode electrode material due to its physical and chemical stability in aqueous and non-toxicity. However, TiO2 has large bandgap (3.0-3.2 eV) that results in absorbing UV light and very small part of visible region. Incorporation of TiO2 in α-Fe2O3 could achieve better efficiencies as photoanode materials by enhancing the electric conductivity, limited hole diffusion length, and both materials can absorb light in both UV and visible spectrum range. However, the photoanodic properties of α-Fe2O3 with different concentrations of TiO2 are mostly unknown. Under this work, α-Fe2O3-TiO2 nanomaterial was synthesized using a hydrothermal method. The α-Fe2O3-TiO2 nanomaterials containing different weight percentage (2.5, 5, 16, 25, and 50) of TiO2 to α-Fe2O3 were characterized using SEM, XRD, UV-Vis, FTIR and Raman techniques, respectively. The electrochemical properties of α-Fe2O3-TiO2 nanomaterials were investigated by cyclic voltammetry and chronoamperometry techniques, respectively.