Scientometric trends and knowledge maps of global polychlorinated naphthalenes research over the past four decades.

Polychlorinated naphthalenes (PCNs) were included in the banned list of the Stockholm Convention due to their potential to provoke a wide range of adverse effects on living organisms and the environment. Many reviews have been written to clarify the state of knowledge and identify the research needs of this pollutant class. However, studies have yet to analyse the scientometric complexities of PCN literature. In this study, we used bibliometric R and vosviewer programs as a scientometric tool to fill this gap by focusing on articles indexed on Web of Science and Scopus databases and those published between 1973 and 2022. A total of 707 articles were published within this period with a publication/author, author/publication, and co-authors/publication ratios of 0.45, 2.19, and 4.86, respectively. Developed countries dominated most scientometric indices (number of publications, citations, and collaboration networks) in the survey period. Lotka's inverse square rule of author productivity showed that Lotka's laws do not fit PCN literature. An annual percentage growth rate of 7.46% and a Kolmogorov-Smirnoff goodness-of-fit of 0.88 suggests that more output on PCNs is likely in years to come. More research is needed from scholars from developing countries to measure the supremacy of the developed nations and to effectively comply with the Stockholm Convention agreement.

Ecotoxicological impact of dinotefuran insecticide and its metabolites on non-targets in agroecosystem: Harnessing nanotechnology- and bio-based management strategies to reduce its impact on non-target ecosystems.

The class of insecticides known as neonicotinoid insecticides has gained extensive application worldwide. Two characteristics of neonicotinoid pesticides are excellent insecticidal activity and a wide insecticidal spectrum for problematic insects. Neonicotinoid pesticides can also successfully manage pest insects that have developed resistance to other insecticide classes. Due to its powerful insecticidal properties and rapid plant absorption and translocation, dinotefuran, the most recent generation of neonicotinoid insecticides, has been widely used against biting and sucking insects. Dinotefuran has a wide range of potential applications and is often used globally. However, there is growing evidence that they negatively impact the biodiversity of organisms in agricultural settings as well as non-target organisms. The objective of this review is to present an updated summary of current understanding regarding the non-target effects of dinotefuran; we also enumerated nano- and bio-based mitigation and management strategies to reduce the impact of dinotefuran on non-target organisms and to pinpoint knowledge gaps. Finally, future study directions are suggested based on the limitations of the existing studies, with the goal of providing a scientific basis for risk assessment and the prudent use of these insecticides.

A bibliometric analysis of pre- and post-Stockholm Convention research publications on the Dirty Dozen Chemicals (DDCs) in the African environment.

Persistent organic pollutants (POPs) are toxic chemicals that stay in the environment for a long time. To address the toxicity issues, global nations, including 53 African countries, ratified the Stockholm Convention to minimize or eliminate the production of 12 POPs known as the "Dirty Dozen". However, these Dirty Dozen Chemicals (DDCs) still exist in significant concentration in the African environment, prompting numerous research to investigate the level of their occurrences. Here, we conducted a bibliometric analysis to examine the publication trends in DDCs-related research in Africa using articles published between 1949 and 2021 from the Web of Science and Scopus databases. A total of 884 articles were published within the survey period, with a publication/author and author/publication ratio of 0.36 and 2.76, respectively. South Africa ranked first in terms of number of publications (n = 133, 15.05%), and total citations (n = 3115), followed by Egypt (n = 117), Nigeria (n = 77), USA (n = 40), and Ghana (n = 38). Research collaboration was relatively high (collaboration index = 2.88). The insignificant difference between the theoretical and observed Lotka's distribution indicates Lotka's law does not fit the DDC literature. An annual growth rate of 0.57% implies that a substantial increase of articles in years to come is not expected. More research programs should be established in other African countries to measure up to South Africa's supremacy. This is critical in order to provide a basis for effective compliance to the Stockholm Convention on POPs in Africa.

Bullet-like microstructured nickel ammonium phosphate/graphene foam composite as positive electrode for asymmetric supercapacitors.

Unique microstructured nickel ammonium phosphate Ni(NH4)2(PO3)4·4H2O and Ni(NH4)2(PO3)4·4H2O/GF composite were successfully synthesized through the hydrothermal method with different graphene foam (GF) mass loading of 30, 60 and 90 mg as a positive electrode for asymmetric supercapacitors. The crystal structure, vibrational mode, texture and morphology of the samples were studied with X-ray diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis and scanning electron microscopy (SEM). The prepared materials were tested in both 3-and 2-electrode measurements using 6 M KOH electrolyte. The composite material Ni(NH4)2(PO3)4·4H2O/60 mg exhibited a remarkable gravimetric capacity of 52 mA h g-1, higher than the 34 mA h g-1 obtained for the Ni(NH4)2(PO3)4·4H2O pristine sample, both at 0.5 A g-1. For the fabrication of the asymmetric device, activated carbon from pepper seed (ppAC) was used as a negative electrode while Ni(NH4)2(PO3)4·4H2O/60 mg GF was adopted as the positive electrode. The Ni(NH4)2(PO3)4·4H2O/60 mg GF//ppAC asymmetric device delivered a specific energy of 52 Wh kg-1 with an equivalent specific power of 861 W kg-1 at 1.0 A g-1 within a potential range of 0.0-1.5 V. Moreover, the asymmetric device displayed a capacity retention of about 76% for over 10 000 cycles at a high specific current of 10.0 A g-1.

Deciphering the Structural, Textural, and Electrochemical Properties of Activated BN-Doped Spherical Carbons.

In this study, the effect of K2CO3 activation on the structural, textural, and electrochemical properties of carbon spheres (CSs) and boron and nitrogen co-doped carbon spheres (BN-CSs) was evaluated. Activation of the CSs and BN-CSs by K2CO3 resulted in increased specific surface areas and ID/IG ratios. From the X-ray photoelectron spectroscopy (XPS) results, the BN-CSs comprised of 64% pyridinic-N, 24% pyrrolic-N and 7% graphitic-N whereas the activated BN-CSs had 19% pyridinic-N, 40% pyrrolic-N and 22% graphitic-N displaying the effect of activation on the type of N configurations in BN-CSs. A possible BN-co-doping and activation mechanism for the BN-CSs is proposed. Electrochemical analysis of the electrode materials revealed that BN doping, carbon morphology, structure, and porosity played a crucial role in enhancing the capacitive behavior of the CSs. As a proof of concept, a symmetric device comprising the activated BN-CSs displayed a specific power of 800 W kg-1 at a specific current of 1 A g-1 within an operating cell potential of 1.6 V in a 3 M KNO3 electrolyte. The study illustrated for the first time the role of K2CO3 activation in influencing the physical and surface properties of template-free activated BN-CSs as potential electrode materials for energy storage systems.

Electrochemical analysis of Na-Ni bimetallic phosphate electrodes for supercapacitor applications.

Bimetallic sodium-nickel phosphate/graphene foam composite (NaNi4(PO4)3/GF) was successfully synthesized using a direct and simple precipitation method. The hierarchically structured composite material was observed to have demonstrated a synergistic effect between the conductive metallic cations and the graphene foam that made up the composite. The graphene served as a base-material for the growth of NaNi4(PO4)3 particles, resulting in highly conductive composite material as compared to the pristine material. The NaNi4(PO4)3/GF composite electrode measured in a 3-electrode system achieved a maximum specific capacity of 63.3 mA h g-1 at a specific current of 1 A g-1 in a wide potential range of 0.0-1.0 V using 2 M NaNO3 aqueous electrolyte. A designed and fabricated hybrid NaNi4(PO4)3/GF//AC device based on NaNi4(PO4)3/GF as positive electrode and activated carbon (AC) selected as a negative electrode could operate well in an extended cell potential of 2.0 V. As an assessment, the hybrid NaNi4(PO4)3/GF//AC device showed the highest energy and power densities of 19.5 W h kg-1 and 570 W kg-1, respectively at a specific current of 0.5 A g-1. The fabricated device could retain an 89% of its initial capacity with a coulombic efficiency of about 94% over 5000 cycling test, which suggests the material's potential for energy storage devices applications.

Hydrothermal synthesis of manganese phosphate/graphene foam composite for electrochemical supercapacitor applications.

Manganese phosphate (Mn3(PO4)2 hexagonal micro-rods and (Mn3(PO4)2 with different graphene foam (GF) mass loading up to 150mg were prepared by facile hydrothermal method. The characterization of the as-prepared samples proved the successful synthesis of Mn3(PO4)2 hexagonal micro-rods and Mn3(PO4)2/GF composites. It was observed that the specific capacitance of Mn3(PO4)2/GF composites with different GF mass loading increases with mass loading up to 100mg, and then decreases with increasing mass loading up to 150mg. The specific capacitance of Mn3(PO4)2/100mg GF electrode was calculated to be 270Fg-1 as compared to 41Fg-1 of the pristine sample at a current density of 0.5Ag-1 in a three-electrode cell configuration using 6M KOH. Furthermore, the electrochemical performance of the Mn3(PO4)2/100mg GF electrode was evaluated in a two-electrode asymmetric cell device where Mn3(PO4)2/100mg GF electrode was used as a positive electrode and activated carbon (AC) from coconut shell as a negative electrode. AC//Mn3(PO4)2/100mg GF asymmetric cell device was tested within the potential window of 0.0-1.4V, and showed excellent cycling stability with 96% capacitance retention over 10,000 galvanostatic charge-discharge cycles at a current density of 2Ag-1.