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http://hdl.handle.net/20.500.11837/3244

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Electrochemical signature of CuS photosensitizers thermalized from alkyldithiocarbamato Cu(II) molecular precursors for quantum dots sensitized solar cells
(Elsevier, 2020-12-10) Agoro, Mojeed A. 0000-0002-0434-9635; Mbese, Johannes Z. 0000-0001-9136-9302; Meyer, Edson L. 0000-0002-9912-311X; Onyenankeya, Kevin 0000-0001-5814-8823
Environmental friendly and affordable energy sources is one of the biggest challenges of modern society. The substantial negative impact of fossil fuels on the environment has prompted the need for clean and sustainable solar energy. Recent reports affirm that increase in photovoltaic conversion efficiency is directly linked to morphology control resulting in excellent catalytic activity on the active layer. Herein, we report on the fabrication of (H is the addition of hexadecylamine HDA capping agents CuSH) and (CuS without HDA) photosensitizers using molecular precursor approach. The obtained CuS-H and CuS were characterized using structural, morphological and electrochemical instruments. The CV, EIS and bode plot results show that CuS displayed stronger electrocatalytic activity as a good optimum sensitizer. J-V efficiency obtained indicates that the CuS exhibited a much better efficiency in the QDSCs compared to CuS-H.
Energy manipulation of isonitrogenous diets for broiler chickens
(South African Society for Animal Science, 2021-01-06) Akinmoladun, O.F.; Falowo,A.B.
A total of 378 unsexed Anak broiler chicks were used to assess the effects of varying energy levels and manipulation on growth, haematology, and carcass traits. The experiment was conducted in two phases. First, one-day-old chicks were randomly assigned to one of three starter diets, which differed in their energy density (LSE: 2786.80 Kcal/kg; OSE: 3015.40 Kcal/kg; and HSE: 3252.20 Kcal/kg). The chicks were assigned to seven replicates per treatment with 18 chicks per replicate. When the chicks were 27 days old, they were randomly re-allocated to three finisher diets (LFE: 2770.66 Kcal/kg, OFE: 2961.74 Kcal/kg, and HFE: 3150.43 Kcal/kg). Thus, there were seven replicates of nine treatments with six chicks per replicate in the finishing phase. The starter and finisher diets were isonitrogenous. Birds fed the OSE and HSE starter diets gained more weight and were heavier at 27 days than birds fed LSE. Energy intake by birds fed HSE was greater than by birds fed OSE, and birds fed OSE had greater energy intake than birds fed LSE. Feed conversion ratio was improved for birds fed OSE and HSE. Birds fed LSE and then HFE consumed the least feed and gained as much or more weight during the finisher phase as any other group. Overall, FCR between days 27 and 50 tended to differ among the treatments (P =0.06). Total protein intake increased with decreasing dietary energy in both phases. Varying dietary energy levels did not affect the haematological parameters, carcass traits and internal organ weights.
Inorganic Pb(II)−P and Pb(II)−S Complexes as Photosensitizers from Primary and Secondary Amines in Dyes-Sensitized Solar Cells
(American Chemical Society, 2021-09-03) Agoro, Mojeed A. 0000-0002-0434-9635; Mbese, Johannes Z. 0000-0001-9136-9302; Meyer, Edson L. 0000-0002-9912-311X
Pb(II) complexes of bis(N-1,4-phenyl-N-(4-morpholinedithiocarbamato)) as Pb(II)−S and bis(N-diisopropyl-Noctyldithiocarbamato) as Pb(II)−P were prepared and characterized by optical, structural, morphological, and electrochemical techniques. The scanning electron microscopy analysis of Pb(II)−P and Pb(II)−S complexes consists of cubic crystals. X-ray diffraction and high-resolution transmission electron microscopy spectral studies revealed that the diameter increases in length for alkyl chain groups. This study demonstrates that the cubic shape of Pb(II) complexes can be synthesized from aromatic and aliphatic dithiocarbamate ligands. Photoluminescence analysis of both complexes fell within the blue shift region. The CV curve for Pb(II)−S revealed redox curves and the box-like shape as an indicative of a capacitive behavior, signifying limited catalytic redox activity. The J−V results for both sensitizers displayed satisfactory conversion efficiency (% η) between 3.77 and 3.96%.
Global Research Trends on Shale Gas from 2010–2020 Using a Bibliometric Approach
(MDPI, 2022-03-16) Baiyegunhi, Temitope Love; Baiyegunhi, Christopher; Pharoe, Benedict Kinshasa; Smoliński, A.
In the last few decades, shale gas resources have attracted much global attention as potential sources for clean and affordable energy. Due to this fact, coupled with the increasing energy shortfall, shale gas has become an increasingly attractive energy prospect from both an environmental and economic perspective. This development has led to the rapid growth in the number of researchersand publications in the field of shale gas. Although there are few review articles on the state of research on shale gas, the literature lacked a bibliometric analysis. This study is intended to fill the research gap by carrying out a bibliometric analysis of 9247 shale gas articles that were published between 2010 and 2020. The Web of Science database was used to collect the data. The analysis was performed to identify the most productive authors, institutions, countries, and sources, and to visualize existing collaborations as well as provide valuable information which could form the basis for establishing future collaboration. The analysis results revealed that Li J has the highest number of publications on shale gas whereas Loucks RG is the most cited author. The top three countries with the highest number of publications in shale gas research are China, USA, and Canada, while the China University of Petroleum (Beijing), China University of Geosciences, and Southwest Petroleum University China were the three top institutions with the highest number of publications. Fuel, International Journal of Coal Geology, and Marine and Petroleum Geology are the journals with the highest number of published articles on shale gas. The keyword analysis indicated that shale gas, hydraulic fracturing, pore structure, permeability, adsorption, kinetics, pyrolysis, organic matter, thermal maturity, and numerical simulation are the predominant research topics. This showed the multi-dimensional and multi-faceted character of the shale gas field. Besides, it appeared to be an exciting topic for further study that is based on a detailed evaluation of the shale gas literature. In fact, shale gas, hydraulic fracturing (fracking), CO2 sequestration, kinetic, gas adsorption, diffusion, and simulation are becoming emerging research hotspots. The bibliometric analysis that was presented in this study has revealed valuable information about the most active institutions and countries, and the most influential authors in the field of shale gas which could form the basis for establishing future collaboration. Furthermore, it can help researchers to understand the global research trend in shale gas as well as provide references for establishing future research directions.
Aliphatic mixed ligands Sn(II) complexes as photon absorbers in quantum dots sensitized solar cell
(Elsevier, 2022-04) Agoro, Mojeed A. 0000-0002-0434-9635; Meyer, Edson L. 0000-0002-9912-311X; Mbese, Johannes Z. 0000-0001-9136-9302; Fuku, Xolile 0000-0001-8247-109X; Ahia, Chinedu C. 0000-0002-5666-1823
Dye-sensitized solar cells have attracted a lot of research interest due to the quest for an alternative energy supply given that it is cost-effective and its materials are easily available. However, the need to improve the conversion efficiency of these solar cell devices has necessitated the search for new materials that will lead to more energy conversion. One of such material of interest is tin (II) sulfide (SnS). In present study, we report results from the synthesis of hexadecylamine (HDA)-capped SnS and uncapped SnS photosensitizer using a molecular precursor. The efficiency of the photon absorbers, their morphological, structural and electrochemical properties were examined using different techniques. Both photosensitizers displayed X-ray diffraction (XRD) peaks within the range 26.03 –66.05 , which corresponds to orthorhombic structure. Field Emission Scanning Electron Microscope (FE-SEM) and High-Resolution Transmission Electron Microscope (HRTEM) further revealed that HDA-capped SnS has a better morphology and size distribution. UV–Vis analysis shows that the HDA-capped SnS exhibits strong absorption in the entire visible region which is attributed to perfect orientation. The HDA-capped photosensitizer superiority was linked to well reduced electron recombination and electron lifetime. The addition of HDA capping agent improved the J-V performance with a new conversion efficiency of 8.20%. Results obtained from present work proselytize the concept of using capping agent as an approach for improving the quality of photon absorbers.
Seasonal variations and associated health risks of polychlorinated naphthalenes in Markman Canal, Eastern Cape Province, South Africa
(Springer, 2022-07-01) Agunbiade, Idowu Victoria; Adeniji, Abiodun Olagoke; Okoh, Anthony Ifeanyi; Okoh, Omobola Oluranti
This study focused on evaluation of the levels, seasonal variations and human health risks associated with polychlorinated naphthalenes (PCNs) in water and sediment samples of Markman Canal using solid phase and soxhlet extraction methods respectively, followed by clean-up and quantification with gas chromatograph coupled with microelectron capture detector. The sum of eight PCNs congener’s (∑8PCNs) in water and sediments varied from 0.035 to 0.699 μg/L and 0.260 to 6744.16 μg/kg dw, respectively. Highest PCNs concentrations were recorded in water during winter, while sediment samples collected during spring contained maximum levels. The estimated toxic equivalency (TEQ) for water and sediments was 1.19× 10–7–1.47× 10-4 µg/L and 4.43× 10−5–4.19× 10−1 µg/kg consecutively. The PCN levels and TEQ values revealed that this waterbody is polluted but constitutes no excess health risk. Efforts should be made to control all the activities contributing to pollution of this canal.
Roles of TOPO Coordinating Solvent on Prepared Nano-Flower/Star and Nano-Rods Nickel Sulphides for Solar Cells Applications
(MDPI, 2022-09-28) Agoro, Mojeed A. 0000-0002-0434-9635; Meyer, Edson L. 0000-0002-9912-311X
The present study describes a cheap, safe, and stable chemical process for the formationof nickel sulphide (NiS) with the use of mixed and single molecular precursors. The productionpathway is uncomplicated, energy-efficient, quick, and toxic-free, with large-scale commercialization potential. The obtained results show the effect of tri-N-octylphosphine oxide (TOPO) as a coordinating solvent on the reaction chemistry, size distributions, morphology, and optical properties of both precursors. Ni[N,N-benz-N-p-anisldtc] as NiSa, Ni[N,N-benzldtc] as NiSb, and Ni[N-p-anisldtc] as NiSc thermally decompose in a single step at 333–334 ◦C. The X-ray diffraction peaks for NiSa, NiSb, and NiSc matched well with the cubic NiS nanoparticles and corresponded to planes of (111), (220), and (311). The extrapolated linear part from the Tauc plots reveals band gap values of 3.12 eV, 2.95 eV, and 2.5 eV, which confirms the three samples as potential materials for solar cell applications. The transmission electron microscopy (TEM) technique affirmed the quantum dot size distribution at 19.69–28.19 nm for NISa, 9.08–16.63 nm for NISb, and 9.37–10.49 nm for NISc, respectively. NiSa and NiSc show a clearly distinguishable flower/star like morphology, while NiSb displays a compact nano-rod shape. To the best of the authors’ knowledge, very few studies have been reported on the flower/star like and nano-rod shapes, but none with the dithiocarbamate molecular precursor for NiS nanoparticles.
Proficient One-Step Heat-Up Synthesis of Manganese Sulfide Quantum Dots for Solar Cell Applications
(MDPI, 2022-10-07) Agoro, Mojeed A 0000-0002-0434-9635; Meyer, Edson L. 0000-0002-9912-311X
The necessity to develop renewable energy resources that are highly durable and flexible with superior energy density and capacitance ability has attracted considerable interest in the field of solar cell research. Semiconducting compound materials that are easily available, hazard-free and cost-effective are emerging as potential solutions to tackle this challenge. Herein, we present multiple molecular precursors used to grow manganese sulfide nanoparticles through a proficient one-step heat-up approach. For all of the tested samples, the X-ray diffraction peaks correspond to a γ-MnS hexagonal wurtzite structure. UV-Vis spectroscopy yielded absorption wavelengths of 359–420 nm and band-gap energies of 3.78–4.0 eV. Photoluminescence analysis shows characteristics of red and blue shift from 451–602 nm. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) reveal a narrow size distribution with nanosticks and large contact areas, which are critical for improved catalytic performance. The current study provides an improved pathway to a well-grown and uniform nanocrystal structure for applications in energy devices.
FeS/FeS2 nanoscale structures synthesized in one step from Fe(ll) dithiocarbamate complexes as a single source precursor
(Frontiers, 2022-12-02) Agoro, Mojeed A 0000-0002-0434-9635; Meyer, Edson L. 0000-0002-9912-311X
Nanoscale FeS and FeS2 mixed phases were synthesized by one-pot decomposition of (N-anil-N-piperldtc)Fe1 as FeS#1), (N-piperldtc)Fe2 as FeS#2) and (N-anildtc)Fe3 as FeS#3) complexes as precursors, with the help of tri-n-octylphosphine oxide (TOPO) coordinating solvent. Their morphology, stability, size, optical and structural characteristics were observed using various material characterization instruments. In comparison to the FeS#2 nano-flower shape, FeS#1 and FeS#3 have a uniform nano-rod shape. A one-step decomposition pattern was obtained from the thermal gravimetric analysis (TGA) results with 3% final mass residual. The high-resolution transmission electron microscopy (HRTEM) image reveals an aggregation and size diameter of around 14.47–30.25 nm for the three samples. The optical response between 3.8 and 4.2 eV from the three samples shows that they are inconsiderable materials for solar cells application. The diffraction peaks for the three samples matched well with the FeS/FeS2. These nanoscale materials can be used in a variety of applications, including lithium-ion batteries, biosensors, hydrogen evolution, and multifunctional nanocomposite materials.
Influence of a One-Pot Approach on a Prepared CuS Macro/Nanostructure from Various Molecular Precursors
(MDPI, 2023-06-24) Agoro, Mojeed A.; Meyer, Edson L.; Gulino, A.
Nanostructured metal sulfides such as copper sulfide (CUS) form from single-source precursors (SSPs) and are cost-friendly materials that can be used in a one-pot approach with potential applications in dye-sensitizer solar cells (DSCs). This is an attractive pathway that allows the careful control of tailoring the design of the nanostructures with slight variations in the mixture conditions to form uniform nanoparticles and enhance the performance of DSCs. We report on the optical, structural, and morphological properties of CuS as photosensitizers and their application in QDSCs using characterization techniques such as cyclic voltammetry (CV), current–voltage (I-V), UV-Vis spectroscopy (UV-Vis), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), etc. The UV-Vis reveals that the band gap for the three samples is found at 2.05–2.87 eV, confirming them as suitable materials for solar cells. The XRD peaks for the three CuS nanoparticles harmonized very well with hexagonal CuS. The thermal gravimetric (TGA) suitability of the three complexes shows a two-step decomposition within the temperature range of 125–716 ◦C, with a final residue of 2–4%. CV curves for three samples show that none of the developed metal sulfides exhibits a peak indicative of limited catalytic activity in the iodine electrolyte. The I-V overall energy conversion efficiency (η%) of 4.63% for the CuSb photosensitizer is linked to the wide electronic absorption spectrum and better relative dye loading. The synthesis of photosensitizers from a trioctylphosphine oxide (TOPO) capping agent shows improved efficiency compared to our previous studies, which used hexadecylamine as a coordinating solvent.
Efficacy of co‑loading Ag nanoparticles and metronidazole in PEG–gelatin‑based sponges for the treatment of chronic wounds
(Springer, 2023-08-07) Alven, Sibusiso; Adeyemi, S.A.; Ubanako, Philemon; Nditheh, D.T.; Choonara, Yahya Essop; Aderibigbe, Blessing A.
Polymer-based sponges loaded with antibacterial agents are potential wound dressings ideal for treating bacteria-infected wounds. Gelatin/poly (ethylene glycol) (PEG) sponge-based wound dressings loaded with metronidazole and Ag nanoparticles with different degrees of cross-linking were prepared, and their capability to treat infected wounds in vitro was evaluated. The degree of cross-linking of the sponges varied, and the porosity of the sponges was in the range of 15.64–91.10%. The amount of gelatin used to prepare the sponges influenced the porosity of the sponges. The sponges displayed an initial burst drug release of metronidazole followed by a sustained release profile. The sponges exhibited considerable antibacterial activity against Gram-positive and Gram-negative bacteria. The % cell viability of the sponges was in the range of 71.17–86.10%, indicating distinguished biocompatibility. The in-vitro experiment showed that the sponge loaded with metronidazole, SAM2%, displayed a significant reduction of 66.68% in the scratch area compared to the sponge loaded with a combination of silver nanoparticles and metronidazole with a closure rate of 46.61% at 96 h. The promising features of the sponges indicate that they are potential wound dressings for treating infected wounds.

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