Zia Ur Rehman

Introduction: Water pollution, stemming from various sources such as pharmaceuticals waste, pesticides, herbicides, textile dyes, resins, and phenolic compounds, is a significant concern in today’s world. Even small amounts of water pollutants can have detrimental effects on human health and ecosystems. Therefore, proper treatment of industrials wastewater through sewage treatment plants is essential for effective wastewater management. Method: In this study, undoped TiO ₂ and silver-doped TiO ₂ nanoparticles were synthesized via Sol-Gel method and thoroughly characterized using X-Ray Diffraction (XRD), UV-Visible Spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-rays (EDX), and Fourier Transform Infrared Spectroscopy (FT-IR). Results: Results revealed a red shift in the UV-Visible spectrum, with increasing silver percentage (2%–4% weight), and silver doping effectively tuned the band gap from undoped TiO ₂ from 3.03 eV to 2.47. XRD analysis revealed an average crystallite size range of 8–12 nm. SEM studies demonstrated morphological changes due to doping, while EDX confirmed the elemental composition of the nanoparticles. FT-IR analysis affirmed sample purity and vibrations of the required functional groups. Discussion: The synthesized nanoparticles exhibited efficient degradation of Malachite Green and Rose Bengal dyes under varied conditions, with 2% weight TiO ₂ displaying the highest Photodegradation Efficiency (PDE) of 98% for Malachite Green at optimal conditions of 4 mg catalyst concentration, 85 μM dye concentration, and pH 9 and 2 mg catalyst concentration, 10 μM dye concentration, and pH 3 for Rose Bengal. Kinetic analysis revealed pseudo first order kinetics with observed rate constant of 0.9438 min ^-1 for Malachite Green and 0.18118 min ^-1 for Rose Bengal, supporting the efficiency of heterogeneous photocatalysis for wastewater treatment. This study underscores the significance of the optimizing degradation parameter for practical applications.

The energy storage ability of a device highly depends on the morphology of the materials used. A structure-directing agent (SDA) can be used to design materials with a specific surface morphology. Zeolite imidazole (ZIF-67) is a favorable electroactive material for energy storage devices. Here, we present a novel approach for synthesizing a ZIF-67 derived NiCo layer double hydroxide hollow surface sheet like morphology, in which potassium fluoroborate acts as a SDA. The hollow sheets possess the largest specific capacitance of 1171 F g⁻¹ at 1 A g⁻¹. The energy storage device composed of ZIF-67 derivatives and a carbon electrode presents a maximum energy density of 26 W h kg⁻¹ at a power density of 804 W kg⁻¹. The device shows good cyclic stability of 84% after 10 000 charge–discharge cycles. These outcomes reveal the promising potential of zeolite imidazole (ZIF-67)-based materials for use in next-generation energy storage devices.

This research examines the synthesis of Co₃O₄–MWCNTs nano-hybrid structures and their incorporation into PVDF polymer for electrical and thermal properties.

In this work, the question is whether the positive charge or the confirmation of side chain of an ionic liquid l-methylimidazolium bromide or the modified solid support multi-walled carbon nanotubes affects the heterogeneous crystallization of melt-crystallized polyvinylidene fluoride. The percentage (%) weight of polyvinylidene fluoride, ionic liquid and multi-walled carbon nanotubes were sequentially dissolved into DMF and stirred for 2 h at 40 °C. The homogeneous solutions were poured into petri-dishes to solidify. The samples P0, P1, P2, P3, P4, P5 were characterized via FTIR, SEM, DSC and XRD. The data obtained solidly supported the investigation. The concentration of ionic liquid was optimized according to the system employed. It was confirmed that multi-walled carbon nanotubes accelerate heterogeneous nucleation of polyvinylidene fluoride as usual, but the formed crystals are dominantly nonpolar α form. Incorporation of only ionic liquid results in depression of the polyvinylidene fluoride melting crystallization rate due to the inherent plasticity of ionic liquid but generates higher content of polar β and γ crystals. The structural spherulites were deformed in case of ionic liquid utilization. The ionic liquid’s loaded solid supports multi-walled carbon nanotubes synergistically enhancing both nucleation and polar phase formation. The immiscibility and non-compatibility of the ionic liquid generated a unique stressed structure with delayed crystallization in the form of necklace-like structure on the composite surface clearly depicted from SEM data.

In this study, a simple in situ technique followed by hydrothermal method is used to synthesize a novel tremella-like structure of ZIF-67Co(OH)F@Co₃O₄/CC metal–organic framework (MOF) derived from zeolite imidazole.

Photocatalytic hydrogen (H₂) production is regarded as an efficient method for generating renewable energy. Despite recent advancements in photocatalytic water splitting, the solar-to-hydrogen conversion efficiency of photocatalysts remains well below the 10% target needed for commercial viability due to ongoing scientific challenges. This review comprehensively analyzes recent advancements in nanoscale engineering of photocatalytic materials, emphasizing techniques to enhance photogenerated charge separation for efficient solar hydrogen production. Here we highlight the nanoscale engineering strategies for effective charge separation including crystal engineering, junction engineering, doping-induced charge separation, tailoring optoelectronic properties, hierarchical architecture, defects engineering, various types of heterojunctions, and polarity-induced charge separation, and discuss their unique properties including ferroelectric on spatial charge separation along with the fundamental principles of light-induced charge separation/transfer mechanisms, and the techniques for investigation. This study, critically assesses strategies for effective photogenerated charge separation to enhance photocatalytic hydrogen production and offers guidance for future research to design efficient energy materials for solar energy conversion.

Transition-metal chalcogenides (MSx) have been shown to be promising low-cost cocatalysts for photocatalytic H2 production. Their performance as cocatalysts, however, is limited due to lack of exposed sulfur (S) sites due to their strong binding with adsorbed atomic hydrogen (S-H). To address this issue, Herein, we demonstrate a unique approach via surface doping of phosphorus (P) atoms into CdS nanorods and fabricated NiS on CdS-P to maintain active site-electron enriched control and electronic structural modification of active S sites. Such a simple nanostructured design exhibits a remarkable improvement in photocatalytic H2 production as 44.39 mmol g-1h-1 under visible light, with an apparent quantum efficiency of 41% at ~ 420 nm. This enhanced photocatalytic hydrogen evolution has been attributable to the modified internal electric field, which accelerates electrons to the surface of NiS for the reduction of hydrogen into H2 instead of adhering to it. Various characterization, such as XPS demonstrate phosphorous doping play a key role in transferring of free electron from CdS to NiS to induce electron-enriched Sδ- active centers resulting in a decrease S-H binding force and boosting photocatalytic hydrogen production. This work describes a broad method for maintaining the number of active sites while tailoring the binding strength between active sites and hydrogen adsorbates.

Herein, a unique synthetic approach called microemulsion is used to create nickel nanoparticles (Ni-NPs). SEM, TEM, EDX, and XRD techniques were employed for the investigation of morphology and structures of the synthesized material. Electrons from electroactive components are transferred to external circuits by Ni-NPs’ superior electrical conductivity and interconnected nanostructures, which also provide a large number of channels for ion diffusion and additional active sites. The experimental findings showed that as a positive electrode for supercapacitors (SC), Ni-NPs had an outstanding ability to store charge, with a dominant capacitive charge storage of 72.4% when measured at 10 mV/s. Furthermore, at 1 A/g, Ni-NP electrodes exhibit a maximum capacitance of 730 F/g. Further, the Ni-NP electrode retains 92.4% of its capacitance even for 5000 cycles, highlighting possible applications for it in the developing field of renewable energy. The current study provides a new method for producing high-rate next-generation electrodes for supercapacitors.

Arsenic (III) is a toxic contaminant in water bodies, especially in drinking water reservoirs, and it is a great challenge to remove it from wastewater. For the successful extraction of arsenic (III), a nanocomposite material (ZnO–CuO/g–C₃N₄) has been synthesized by using the solution method. The large surface area and plenty of hydroxyl groups on the nanocomposite surface offer an ideal platform for the adsorption of arsenic (III) from water. Specifically, the reduction process involves a transformation from arsenic (III) to arsenic (V), which is favorable for the attachment to the –OH group. The modified surface and purity of the nanocomposite were characterized by SEM, EDX, XRD, FT–IR, HRTEM, and BET models. Furthermore, the impact of various aspects (temperatures, pH of the medium, the concentration of adsorbing materials) on adsorption capacity has been studied. The prepared sample displays the maximum adsorption capacity of arsenic (III) to be 98% at pH ~ 3 of the medium. Notably, the adsorption mechanism of arsenic species on the surface of ZnO–CuO/g–C₃N₄ nanocomposite at different pH values was explained by surface complexation and structural variations. Moreover, the recycling experiment and reusability of the adsorbent indicate that a synthesized nanocomposite has much better adsorption efficiency than other adsorbents. It is concluded that the ZnO–CuO/g–C₃N₄ nanocomposite can be a potential candidate for the enhanced removal of arsenic from water reservoirs.