Abdul Azeez Peer Mohamed

Role of precursors on the photophysical properties of carbon nitride and its application for antibiotic degradation

In this paper, we provide a comprehensive evaluation of graphitic carbon nitride (C3N4) powders derived from the four different precursors melamine, cyanamide, thiourea, and urea for the photocatalytic degradation of tetracycline (TC) antibiotic under sunlight irradiation. The powders were synthesized by employing the conventional thermal decomposition method. The synthesized powders were examined using different characterization tools for evaluating the photophysical properties. The degradation profile revealed that urea-derived C3N4 showed the highest activity while melamine-derived C3N4 showed the least activity. The TC degradation efficiency of the photocatalyst was found to be influenced more by the surface area values despite extended absorption by melamine in the visible light region. Stability tests on urea-derived C3N4 and others were checked by four runs of TC degradation under sunlight irradiation. The synthesized C3N4 powders also confirmed the dominance of urea-derived powders for cyclic stability.

Fine tuning of compact ZnO blocking layers for enhanced photovoltaic performance in ZnO based DSSCs: a detailed insight using β recombination, EIS, OCVD and IMVS techniques

The electron–hole recombination and back electron flow at the conducting oxide–mesoporous film interface in dye-sensitized solar cells (DSSCs) are addressed primarily by the use of pre-blocking layers. Herein, the effects of zinc oxide (ZnO) blocking layers (BLs) on the photovoltaic performance of ZnO based DSSCs are investigated in detail using electrochemical impedance spectroscopy (EIS), open circuit voltage decay (OCVD) and intensity modulated photovoltage spectroscopic (IMVS) techniques. BLs of varying thicknesses obtained by a low temperature solution process provided uniform surface coverage of nanosized ZnO particles over FTO. Devices with optimized ZnO blocking layer thickness (12 nm) lead to improved performance (efficiency 2.57%) in comparison to the devices fabricated using bare FTO (1.27%) by suppressing interfacial recombination at the FTO/ZnO interface thereby improving the lifetime leading to better performance.

Photoactive, antimicrobial CeO2 decorated AlOOH/PEI hybrid nanocomposite: a multifunctional catalytic-sorbent for lignin and organic dye

In this study an amine functionalized, mesoporous monohydroxy aluminium oxide (AlOOH/PEI) hybrid is prepared and further catalytically engineered with nano-CeO2 to make a multifunctional photoactive and antimicrobial catalytic-sorbent (CeO2@AlOOH/PEI). Structural and physico-chemical properties of this catalytic-sorbent were characterized using powder XRD, FTIR, SEM, TEM, N2 sorption analysis, TGA and zeta-potential measurements. This hybrid catalytic-sorbent is explored for the treatment of industrial waste water contaminated with lignin and organic dye. A comparative study was also done with other known conventional sorbents and the developed CeO2@AlOOH/PEI catalytic-sorbent shows a better adsorption capacity towards lignin. Photodegradation of lignin and methyl orange dye using the CeO2@AlOOH/PEI hybrid nanocomposite was also investigated under sunlight and UV irradiation. Both the pollutants show a better photodegradation under UV. Above all, the antibacterial properties of the CeO2@AlOOH/PEI sorbent were also studied against both Gram-positive (S. aureus) and Gram-negative (E. coli, K. pneumoniae) bacteria and showed efficient antimicrobial activity against these tested bacteria. An eco-friendly, self-regenerative, sustainable CeO2@AlOOH/PEI catalytic sorbent is designed and validated for the recovery of water resources from lignin and dye contaminated industrial effluent.