• Energy Research

The optoelectrical and magnetic characteristics of naturally existing iron-based nanostructures, especially hematite and magnetite nanoparticles (H-NPs and M-NPs), gained significant research interest in various applications, recently. The main purpose of this Review is to provide an overview of the utilization of H-NPs and M-NPs in various environmental remediation. Iron-based NPs are extensively explored to generate green energy from environmental friendly processes such as water splitting and CO2 conversion to hydrogen and low molecular weight hydrocarbons, respectively. The latter part of the Review provided a critical overview to use H-NPs and M-NPs for the detection and decontamination of inorganic and organic contaminants to counter the environmental pollution and toxicity challenge, which could ensure environmental sustainability and hygiene. Some of the future perspectives are comprehensively presented in the final portion of the script, optimiztically, and it is supported by some relevant literature surveys to predict the possible routes of H-NPs and M-NPs modifications that could enable researchers to use these NPs in more advanced environmental applications. The literature collection and discussion on the critical assessment of reserving the environmental sustainability challenges provided in this Review will be useful not only for experienced researchers but also for novices in the field.

In the perspective of fossil fuel depletion, the importance of renewable and substitute fuels is remarkable. In this study, clean liquid-fuel was obtained from tar through catalytic hydrorefining method. Hydrorefining catalysts were prepared by impregnation, containing tungsten-nickel (W-Ni), molybdenum-nickel (Mo-Ni), tungsten-molybdenum-nickel (W-Mo-Ni), and tungsten-molybdenum-cobalt (W-Mo-Co). γ-alumina was used as catalysts supporter. The clean liquid fuel product was analyzed by Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry, elemental analyzer, octane number for gasoline fraction and cetane-number for diesel fraction, and Engler distillation range. The rules of sulfur and nitrogen content were also investigated. The overall product yield was up to 97%, and the sulfur and nitrogen content was less than 70 ppm. The W-Mo-Ni/γ-Al2O3 catalyst showed high performance in catalytic hydrofinishing and good stabilization under required conditions.

The effect of phosphorus catalysts for hydrogenation reactions were studied in this work. Different catalysts supported on γ-Al2O3 containing phosphorus (WNiP/γ-Al2O3, MoNiP/γ-Al2O3, WMoNiP/γ-Al2O3 and WMoCoP/γ-Al2O3) were prepared through ultrasonic-assisted impregnation and temperature-programming methods. The catalytic hydrotreating reaction are under the reaction conditions of PH2=9MPa, Thf=370oC, space velocity=0.5h-1, and H2/oil ratio=1400. Gasoline (≤180oC) and diesel (180–360oC) are separated from the liquid product. The fractions were characterized by Elemental analysis, FTIR, KY3000 S/N and GC-MS analysis. Though analysis of test results, it can be concluded that the WNiP/γ-Al2O3 is the excellent hydrotreating catalyst in this series at this reaction condition.

Abstract An increase in energy demand in the recent decades have created energy shortages that can be fulfilled by the use of fossil fuels. Gasification and reforming techniques are effective methods for producing syngas and hydrogen from natural gas and coal. The two process models have been developed in this study, in which syngas and hydrogen is produced from coal and natural gas. The case 1 relies on the entrained flow gasification unit which is validated by literature data, and then integrated with the reforming process reforming to generate the case 2. The integrated gasifier and reforming model was created to increase H2 output while lowering the total carbon footprints. In case of 2nd model, the hydrogen to carbon monoxide ratio (HCR) is 1.20 which is almost 88% higher than the baseline. Due to the higher HCR in case 2, the overall production of H2 is 55% higher than the case 2. Moreover, the efficiency of case 2 is 18.5% higher which reduces the carbon emissions by 69.6% per unit of hydrogen production compared to case 1.Furthermore, the investment per ton of hydrogen production and hydrogen selling prices in Case 2 is 28.9% lower compared to the case 1 design.

Photocatalysis is a classical solution to energy conversion and environmental pollution control problems. In photocatalysis, the development and exploration of new visible light catalysts and their synthesis and modification strategies are crucial. It is also essential to understand the mechanism of these reactions in the various reaction media. Recently, bismuth and graphene’s unique geometrical and electronic properties have attracted considerable attention in photocatalysis. This review summarizes bismuth-graphene nanohybrids’ synthetic processes with various design considerations, fundamental mechanisms of action, heterogeneous photocatalysis, benefits, and challenges. Some key applications in energy conversion and environmental pollution control are discussed, such as CO2 reduction, water splitting, pollutant degradation, disinfection, and organic transformations. The detailed perspective of bismuth-graphene nanohybrids’ applications in various research fields presented herein should be of equal interest to academic and industrial scientists.

Abstract In this work, electrocatalytic studies of highly active and non-precious metal based Cobalt benzene tricarboxlic acid (Co BTC) metal organic framework (MOF) and its reduced graphene oxide (rGO) composites for oxygen evolution reaction (OER) were performed in an alkaline media by employing cyclic voltammetry. Cobalt based MOF and their rGO composites were solvothermally synthesized. Prepared samples were further characterized for structural and morphological analysis through X-rays diffraction (XRD), scanning electron microscopy (SEM), Fourier transform Infrared (FTIR) spectroscopy and Energy dispersive spectroscopy (EDX) techniques. During CV studies the main emphasis was to observe the effect of rGO concentration on electrochemical response of synthesized materials for OER. Co BTC-5 wt % rGO (Cobalt benzene tricarboxlic acid-reduced graphene oxide) composite with current density of 10 mA/cm2 at over potential 0.29 V vs. RHE proved to be a potential candidate due to its high activity and stability for OER.

The levels of greenhouse gases, and in particular, carbon dioxide (CO2) emissions due to anthropogenic activities, have greatly inflated, and this has contributed to climate fluctuation and global warming. In 2023, the CO2 emissions went up by 1.1 % to arrive at a figure of 37.4 g/t. There is now a good prospect of converting CO2 into other products, thanks to the active research into the use of COFs for CO2 capture and conversion. COFs as a new class of porous crystalline materials are synthesized by organic units linked like benzene and triazine, sanines, and porphyrines. Production procedures may result in COFs impurities, therefore, an activation paragraph is required to outweigh the deficiency and improve the efficiency of the COFs. Even though it is difficult to achieve these characteristics in humid conditions where temperature and pressure are in the normal operating conditions of COFs, their low density, highly porous surface areas, large pore volume, and adjustable pore size, all vice versa are effective in carbon capture. This review focuses on the fact that COFs' structural properties are vital to the success of the CO2 capture and storage processes. It also assesses the possibility of creating cyclic carbonates or other organic compounds to solve environmental issues effectively.

With the dramatic increasing of economy, the conflict between the lack of petroleum resource and sharply increasing demand for gasoline and diesel has restricted the continuous development of economy and energy of our world. The catalytic conversion of C9 aromatics into clean fuel was studied in our laboratory using hydrotreating catalysts which were prepared by new synthesis technologies that combine vacuum-impregnation and temperature-programmed calcinations. Characterization results indicate that these catalysts have a high surface area, and the activity sites dispersed well on the supporter. Hydrogenation performance of reaction conditions was carried out in two-stage fixed beds. Products of gasoline (<180 °C) and diesel (180–360 °C) fractions were separated from intermediate products via distillation, and the analysis results demonstrate that S/N content, density, and viscosity decreased. However, the H/C molar ratio increased. The main reactions of isomerization, disproportionation, and dealkylation occurred during the conversion of C9 aromatics and the activity order accorded the mechanism of carbenium ion reaction. This study indicates that C9 aromatics could be considerably upgraded through catalytic hydroprocessing to high-quality fuel in the presence of high-performance catalysts and appropriate reaction conditions. Thus, they are promising catalytic technologies and materials. Furthermore, the products could substitute gasoline and diesel partly.

Covalent organic frameworks (COFs) are emerging crystalline polymeric materials with highly ordered intrinsic and uniform pores. Their synthesis involves reticular chemistry, which offers the freedom of choosing building precursors from a large bank with distinct geometries and functionalities. The pore sizes of COFs, as well as their geometry and functionalities, can be pre-designed, giving them an immense opportunity in various fields. In this mini-review, we will focus on the use of COFs in the removal of environmentally hazardous metal ions and chemicals through adsorption and separation. The review will introduce basic aspects of COFs and their advantages over other purification materials. Various fabrication strategies of COFs will be introduced in relation to the separation field. Finally, the challenges of COFs and their future perspectives in this field will be briefly outlined.