Mohamed I. Fadlalla

Bio: Mohamed I. Fadlalla is an academic researcher from University of Cape Town. The author has contributed to research in topics: Catalysis & Dehydrogenation. The author has an hindex of 4, co-authored 16 publications receiving 53 citations. Previous affiliations of Mohamed I. Fadlalla include University of KwaZulu-Natal & DST Systems.

Emerging energy and environmental application of graphene and their composites: a review

Abstract: Graphene-based materials receive attention in the field of energy and environmental application. The unique physiochemical assets such as the high surface area, high thermal stability, chemical flexibility, high electron mobility and mechanical solidity make it a highly versatile material for different applications. In this critical review, the application of graphene-based material in energy and environmental remediation is discussed in detail. More specifically, the role of graphene in thought-provoking research fields, viz. solar cell, photocatalytic water splitting, photocatalytic degradation of organic pollutants and heavy metal removal, is focused. As graphene possesses very good carrier mobility, it enhances the photocatalytic performance of semiconducting materials. Very interestingly, graphene is being used in both hole transport layer and electron transport layer in solar cell. Similarly, high surface area of graphene assists in heavy metal removal by adsorption. The challenges and recent achievements in these fields are highlighted in this review.

Support and gas environment effects on the preferential oxidation of carbon monoxide over Co3O4 catalysts studied in situ

Abstract: We have studied the effect of different supports (CeO2, ZrO2, SiC, SiO2 and Al2O3) on the catalytic performance and phase stability of Co3O4 nanoparticles during the preferential oxidation of CO (CO-PrOx) under different H2-rich gas environments and temperatures. Our results show that Co3O4/ZrO2 has superior CO oxidation activity, but transforms to Co0 and consequently forms CH4 at relatively low temperatures. The least reduced and least methanation active catalyst (Co3O4/Al2O3) also exhibits the lowest CO oxidation activity. Co-feeding H2O and CO2 suppresses CO oxidation over Co3O4/ZrO2 and Co3O4/SiC, but also suppresses Co0 and CH4 formation. In conclusion, weak nanoparticle-support interactions (as in Co3O4/ZrO2) favour high CO oxidation activity possibly via the Mars-van Krevelen mechanism. However, stronger interactions (as in Co3O4/Al2O3) help minimise Co0 and CH4 formation. Therefore, this work reveals the bi-functional role required of supports used in CO-PrOx, i.e., to enhance catalytic performance and improve the phase stability of Co3O4.

Recent Advances in Nanomaterials for Wastewater Treatment

Abstract: Developing an efficient wastewater treatment technique is one of the major necessities of the twenty-first century, owing to the scarcity of water resources. Besides, it is of paramount important to find appropriate methodologies to economically treat wastewater. Recent advances in nanotechnology have attracted the attention of many researchers for wastewater treatment. The major advantages of such nanomaterial-based systems are that they can be reused and have been found to be very effective. Though many research works have been reported in this regard, there is very limited collective information. Hence, the major objective of this work is to describe recent achievements in nanomaterial-based systems for wastewater treatment. This chapter critically reviews and lists the uses of nanomaterials in wastewater treatment. This comprises the utilization of semiconducting nanoparticles either alone or combined with ozonation, the Fenton process, or sonolysis for effective degradation/removal of organic pollutants. Furthermore, the effectiveness of nanotechnology in antimicrobial activity to produce pure water via an eco-friendly route is discussed. Similarly, the role of nanomaterials in adsorption techniques (specifically, carbon-based nanoadsorbents) to remove heavy metal contamination from industrial wastewater is also discussed in detail.

Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics

Abstract: We have produced ultrathin epitaxial graphite films which show remarkable 2D electron gas (2DEG) behavior. The films, composed of typically 3 graphene sheets, were grown by thermal decomposition on the (0001) surface of 6H-SiC, and characterized by surface-science techniques. The low-temperature conductance spans a range of localization regimes according to the structural state (square resistance 1.5 kOhm to 225 kOhm at 4 K, with positive magnetoconductance). Low resistance samples show characteristics of weak-localization in two dimensions, from which we estimate elastic and inelastic mean free paths. At low field, the Hall resistance is linear up to 4.5 T, which is well-explained by n-type carriers of density 10^{12} cm^{-2} per graphene sheet. The most highly-ordered sample exhibits Shubnikov - de Haas oscillations which correspond to nonlinearities observed in the Hall resistance, indicating a potential new quantum Hall system. We show that the high-mobility films can be patterned via conventional lithographic techniques, and we demonstrate modulation of the film conductance using a top-gate electrode. These key elements suggest electronic device applications based on nano-patterned epitaxial graphene (NPEG), with the potential for large-scale integration.

Deep eutectic solvent-based manganese molybdate nanosheets for sensitive and simultaneous detection of human lethal compounds: Comparing the electrochemical performances of M-molybdate (M= Mg, Fe, and Mn) electrocatalysts

Abstract: Potentially hazardous chemical contaminants endanger the environment and human well-being, challenging scientists and policy makers to develop holistic alternative approaches for remediation. The addition or accumulation of these chemicals can have a series of far-reaching consequences and have direct and indirect effects at multiple levels of ecological organization. Therefore, the development of a sensitive tool for the comprehensive evaluation of chemical concentrations is highly relevant. Herein, we thus report the simultaneous electrochemical detection of highly toxic hydroquinone (HQ), Hg2+, and nitrite (NO2-) compounds using nanostructured metal molybdate (M = Mg, Fe and Mn) catalysts. These functional nanomaterials are synthesized using a deep eutectic solvent (DES) modified hydrothermal method that provides sustainable aspects and energy efficient synthesis strategies. Choline chloride (ChCl)-urea DES used in this study exhibits an all-in-one behaviour by simultaneously acting as a template, reducing agent, and homogeneous means for stabilizing metal ions. This stimulates the fabrication of hierarchical structures of metal molybdates with high surface activities that cause their remarkable properties with minimal waste generation. The structural, morphological, catalytic, and electrochemical capacities of the as-synthesized MgMoO4, Fe2(MoO4)3, and MnMoO4 materials are explored through various techniques and comparatively, MnMoO4 presents superior characterization features such as a reduced particle size, increased surface area and hierarchical architectures. Owing to the exceptional physicochemical attributes, the MnMoO4 modified glassy carbon electrode (GCE) demonstrates superior electrochemical activities towards the individual and simultaneous detection of HQ, Hg2+, and NO2-. Well-defined and separate peaks are observed for the simultaneous detection of HQ, Hg2+, and NO2- which is influenced by the binding energies of these pollutants. Furthermore, the modified electrode exhibits a high sensitivity of 23.8, 17.7 and 10.2 μA μM-1 cm-2 with a limit of detection (LOD) of 0.026, 0.05, and 0.01 μM for HQ, Hg2+, and NO2- respectively under ideal conditions. Also, the reproducibility and anti-interference ability reinforce the application potential of the MnMoO4 modified electrode for the simultaneous electrochemical detection of HQ, Hg2+, and NO2- in real samples with better recoveries, thus assessing the effect of these hazardous chemicals on humanity.