Muhammad Ahmad

Efficient, durable, and low-cost electrocatalysts for the Oxygen Evolution Reaction (OER) are essential for the improvement of Alkaline Water Electrolysis and sustainable hydrogen production. In this work, a conductive CoMn₂O₄/polyaniline (CoMn₂O₄/PANI) nanohybrid was successfully synthesized via a simple hydrothermal method to overcome the drawbacks of low conductivity and nanoparticle aggregation of pristine CoMn₂O₄. The successful incorporation of the crystalline spinel CoMn₂O₄ nanoparticles into the conductive PANI matrix was confirmed by structural and physicochemical characterization using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), resulting in a porous, interconnected architecture with uniformly distributed catalytic active sites. The synergistic coupling between CoMn₂O₄ and PANI greatly improved electrical conductivity, active-site accessibility, electrolyte penetration, and charge-transfer kinetics. It was found that the CoMn₂O₄/PANI nanohybrid had a low overpotential, 373 mV at 10 mA cm⁻², a small Tafel slope, 57 mV dec⁻¹, a remarkably low charge-transfer resistance, 0.12 Ω, and a sevenfold increase in electrochemically active surface area, 350 cm², compared with pristine CoMn₂O₄. In addition, the nanohybrid also proved to be extremely durable for operation, retaining the same catalytic activity after 50 h of continuous operation in alkaline OER conditions. This superior electrocatalytic activity is explained by the synergistic role of the conductive PANI network and catalytically active CoMn₂O₄ nanoparticles that enable fast electron transport, efficient adsorption of hydroxide ions, fast creation of oxygen-containing intermediates, and structural stability. Most significantly, this work furnishes a complete structure–property–performance relationship that delivers a fundamental understanding of how conductive polymer/spinel oxide hybridization controls the OER activity. The present results show that the hydrothermally synthesized CoMn₂O₄/PANI nanohybrid is an efficient electrocatalyst for oxygen evolution and present design guidelines for designing the next-generation electrocatalysts for water splitting towards sustainable hydrogen energy.

Cosmetics are a staple in daily beauty routines worldwide, embraced for their role in enhancing personal appearance and self-care. However, their direct application exposes the skin to a range of ingredients, including metal(loid)s, and these can have a hazardous impact on human health if they exceed the limits defined by regulatory agencies. As a result, it is important to evaluate metal(loid) levels to ensure the safety of these cosmetic products. This research aimed to analyze several cosmetic products (massage cream, cleaner, mud mask, skin polish, scrub, lipstick, foundation, lotion, face powder, and highlighter) for metalloids (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, As, Sb, Cd, Pb, Bi, and Hg) by using inductively coupled plasma-optical emission spectrometry (ICP-OES). Multivariate and bivariate statistical approaches were used to interpret the sources and association between the metal(loid)s. The concentration ranges of metals were found to be Al (1.18–4.15 mg/kg), Cr (0.13–2.19 mg/kg), Mn (1.89–28.77 mg/kg), Fe (4.09–126.02 mg/kg), Co (0.19–31.62 mg/kg), Ni (0.11–5.39 mg/kg), Cu (0.08–0.19 mg/kg), Zn (1.99–47.81 mg/kg), Sr (0.99–10.34 mg/kg), Cd (0.16–1.50 mg/kg), Pb (0.29–2.44 mg/kg), Bi (0.23–2.18 mg/kg), and Hg (0.012–0.42 mg/kg), whereas the concentration ranges of metalloids were found to be As (0.011–0.051 mg/kg) and Sb (0.042–1.66 mg/kg). Among the tested cosmetic products for the metal(loid) levels, the estimation of the margin of safety (MOS < 100), hazard quotient (HQ > 1), hazard index (HI > 1), and cumulative cancer risk (LCR ≤ 1 × 10⁻³) indicated non-carcinogenic and carcinogenic health risks associated with the use of few products. Most of the cosmetics products under investigation are safe with respect to non-carcinogenic and carcinogenic health risks. By highlighting the need to limit excessive use and adhering to sustainable safety practices, this study underscores the importance of monitoring and regulating metal(loid) content to ensure consumer safety and mitigate environmental impact.

Hydrogen fuel is a clean and versatile energy carrier that can be used for various applications, including transportation, power generation, and industrial processes. Electrocatalytic water splitting could be the most beneficial and facile approach for producing hydrogen. In this work, transition metal selenide composites with carbon nanotubes (CNTs) have been investigated for electrocatalytic water splitting. The synthesis process involved the facile one-step hydrothermal growth of transition metal nanoparticles over the CNTs and acted as an efficient electrode toward electrochemical water splitting. Scanning electron microscopy and XRD patterns reveal that nanoparticles were firmly anchored on the CNTs, resulting in the formation of composites. The electrochemical measurements reveal that CNT composite with nickel–cobalt selenides (NiCo-Se/CNTs@NF) display remarkable oxygen evolution reaction (OER) activity in basic media, which is an important part of hydrogen production. It demonstrates the lowest overpotential (η_10mAcm⁻²) of 0.560 V vs. RHE, a reduced Tafel slope of 163 mV/dec, and lower charge transfer impedance for the OER process. The multi-metallic selenide composite with CNTs demonstrating unique nanostructure and synergistic effects offers a promising platform for enhancing electrocatalytic OER performance and opens up new avenues for efficient energy conversion and storage applications.

Conventional systems of medicine play a crucial role in maintaining healthcare. Herbal medicines are intact and less harmful to human beings than synthetic medicines. This study aimed to investigate the phytochemicals and in vivo hypolipidemic effect of chloroform extract of Lagenaria siceraria in Triton X-100 (100mg/kg body weight) induced hyperlipidemic Wistar rats. The phytochemical characterization and estimation were performed on the base of the GC-MS approach. The Lagenaria siceraria extract (250 and 500mg/kg bw) was administered orally to hyperlipidemic-induced rats for 7days to examine its hypolipidemic activity. The experimental animals did not display any acute toxicity. Atorvastatin (10mg/kg bw) was used as a standard drug. Administration of Lagenaria siceraria extract lowers the total cholesterol (TC), triglyceride (TG), and low-density lipoproteins-cholesterol (LDL-C) levels whereas elevating the high-density lipoproteins-cholesterol (HDL-C) level. Histological studies of the liver and heart also showed the hypolipidemic effect of the extract. On the 8^th day, no inflammation of the liver, myocardial necrosis, fibrosis, or atypia was seen. Furthermore, binding affinity and plausible binding mode of stigmastan-3-ol with HMG-CoA reductase were predicted by molecular docking studies which showed the same interaction patterns as atorvastatin. Moreover, the docking results were refined by 100ns MD simulations which revealed that stigmastan-3-ol extract formed a stable complex with protein and did not induce any conformational changes in protein structure.

Methylene blue (MB) is a most commonly used synthetic dye in the textile industry. It is an extremely carcinogenic phenothiazine derivative and therefore needs to be removed from the water bodies. In the present study, a single-step hydrothermal novel synthesis of carbon quantum dots (CQDs) extracted from biomass of chicken feathers has been performed, and the synthesized CQDs were applied to remove MB present in the aqueous samples. A number of techniques such as ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to characterize the samples for the conformity purposes. SEM and XRD analysis showed that CQDs are highly crystalline and have spherical structures with an average particle diameter of 35 nm. In the presence of 0.2 g of synthesized CQDs, MB dye degraded drastically under the sunlight. The rate of degradation was studied by determining the absorbance of the degraded sample with time relevant to untreated sample. The % degradation achieved during first 60 min of time was approximately 92% which increased minimally to a value of only 95% after 100 min of time. The ease of synthesis of carbon dots at low cost contributes hugely to their utilizations as an efficient photocatalyst for the degradation of aqueous pollutants. The opted approach to synthesize CQDs is cost-effective and eco-friendly and demonstrates excellent potential to remove MB from the aqueous samples.

Most of synthetic dyes are toxic for the environment. On the other hand, natural dyes are ecofriendly and can replace synthetic toxic dyes. In the present studies, a natural dye was extracted from rinsed and grinded olive peel in 1:10 ratio (m/V) with water. Then, fabrics (wool and silk) were dyed with the peel extract by using different types of dulling and shining mordants (FeSO4, CuSO4, CoSO4, SnCl2, K2SO4, Al2(SO4)3, ZnSO4 and NiSO4). The mordants have shown best results for wool at the acidic pH (4-5) and for silk at the basic pH (8-9). After dyeing wool (at 70-80ºC) and silk (at 100ºC) with olive peel extract, by simultaneous mordanting method, an interesting variety of beige, buff and khaki shades were obtained. Color fastness was noted by matching the dyed fabric color with grey scale. The colors of dyed fabric were again noted after its washing, pressing by iron, rubbing and light exposure. The fastness results were found quite satisfactory. The investigated procedure of natural dye extraction is eco-friendly, safe for the environment and a safe technique as it does not involve any organic solvent. The natural dyes can be satisfactory potential substitutes of the synthetic environmentally hazardous dyes.