Highly selective and stable hydrogenation of heavy aromatic-naphthalene over transition metal phosphides

Recent Progress in Polyaniline and its Composites for Supercapacitors

Polyaniline (PANI) has piqued the interest of nanotechnology researchers due to its potential as an electrode material for supercapacitors. Despite its ease of synthesis and ability to be doped with a wide range of materials, PANI's poor mechanical properties have limited its use in practical applications. To address this issue, researchers investigated using PANI composites with materials with highly specific surface areas, active sites, porous architectures, and high conductivity. The resulting composite materials have improved energy storage performance, making them promising electrode materials for supercapacitors. Here, we provide an overview of recent developments in PANI-based supercapacitors, focusing on using electrochemically active carbon and redox-active materials as composites. We discuss challenges and opportunities of synthesizing PANI-based composites for supercapacitor applications. Furthermore, we provide theoretical insights into the electrical properties of PANI composites and their potential as active electrode materials. The need for this review stems from the growing interest in PANI-based composites to improve supercapacitor performance. By examining recent progress in this field, we provide a comprehensive overview of the current state-of-the-art and potential of PANI-based composites for supercapacitor applications. This review adds value by highlighting challenges and opportunities associated with synthesizing and utilizing PANI-based composites, thereby guiding future research directions.

Synthesis, Characterization, and NH3-SCR Catalytic Performance of Fe-Modified MCM-36 Intercalated with Various Pillars

Two series of MCM-36 zeolites intercalated with various pillars and modified with iron were synthesized, analyzed with respect to their physicochemical properties, and tested as catalysts for the NH₃-SCR process. It was found that the characteristic MWW morphology of MCM-36 can be obtained successfully using silica, alumina, and iron oxide as pillars. Additionally, one-pot synthesis of the material with iron resulted in the incorporation of monomeric Fe³⁺ species into the framework positions. The results of catalytic tests revealed that the one-pot synthesized sample intercalated with silica and alumina was the most efficient catalyst of NO reduction, exhibiting ca. 100% activity at 250 °C. The outstanding performance of the material was attributed to the abundance of Lewis acid sites and the beneficial influence of alumina on the distribution of iron species in the zeolite. In contrast, the active centers originating from the Fe₂O₃ pillars improved the NO conversion in the high-temperature range. Nevertheless, the aggregated particles of the metal oxide limited the access of the reacting molecules to the inner structure of the catalyst, which affected the overall activity and promoted the formation of N₂O above 300 °C.

Modification of Activated Carbon and Its Application in Selective Hydrogenation of Naphthalene

The MoS₂/ACx catalyst for hydrogenation of naphthalene to tetralin was prepared with untreated and modified activated carbon (ACx) as support and characterized by X-ray powder diffraction, Brunauer-Emmett-Teller, scanning electron microscopy, temperature-programmed desorption of ammonia, X-ray photoelectron spectroscopy, and scaning transmission electron microscopy. The results show that the modification of activated carbon by HNO₃ changes the physical and chemical properties of activated carbon (AC), which mainly increases the micropore surface area of AC from 1091 to 1209 m²/g, increases the micropore volume of AC from 0.444 to 0.487 cm³/g, increases the oxygen-containing functional groups of AC from 5.46 to 7.52, and increases the acidity of catalysts from 365.7 to 559.2 mmol/g. The modified catalyst showed good catalytic performance, and the appropriate HNO₃ concentration is very important for the modified of activated carbon. Among all the catalysts used in this study, the MoS₂/AC3 catalyst could achieve the highest yield of tetralin. It can be attributed to the moderate acidity of the catalyst, reducing the cracking of hydrogenation products. Also, the proper hydrogenation activity of MoS₂ and the appropriate increase of oxygen-containing functional groups on the surface of modified activated carbon are beneficial to the dispersion of active components on the support, increasing the yield of tetralin. The catalytic performance of MoS₂/AC3 is better than that of MoS₂/Al₂O₃ catalyst, and the two catalysts show different hydrogenation paths of naphthalene.

A Review of Preparation Methods for Heterogeneous Catalysts

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Catalysts contribute significantly to the industrial revolution in terms of reaction rates and reduction in production costs. Extensive research has been documented on various industrial catalysis in the last few decades. The performance of catalysts is influenced by many parameters, including synthesis methods. The current work overviews the most common methods applied for the synthesis of supported catalysts. This review presents the detailed background, principles, and mechanism of each preparation method. The advantages and limitations of each method have also been elaborated in detail. In addition, the applications of each method in terms of catalyst synthesis have been documented in the present review paper.

Catalytic deoxygenation of palm oil over metal phosphides supported on palm fiber waste derived activated biochar for producing green diesel fuel

Palm oil conversion into green diesel by catalytic deoxygenation (DO) is one of the distinctive research topics in biorefinery towards a bio-circular-green economic model to reduce the greenhouse gas emissions. In this study, palm fiber waste was explored as an alternative precursor for the preparation of activated biochar as a support material. A new series of nickel phosphide (Ni–P) and iron phosphide (Fe–P) catalysts supported on palm fiber activated biochar (PFAC) was synthesized by wetness impregnation, and extensive characterization was performed by several techniques to understand the characteristics of the supported metal phosphide catalysts prior to palm oil deoxygenation for producing of green diesel (C₁₅–C₁₈ hydrocarbons). The PFAC support exhibited suitable physicochemical properties for catalyst preparation, such as high carbon content, and high porosity (S_BET of 1039.64 m² g⁻¹ with V_T of 0.572 cm³ g⁻¹). The high porosity of the catalyst support (PFAC) significantly promotes the metal phosphide nanoparticle dispersion. The DO of palm oil was tested in a trickle bed down flow reactor under hydrogen atmosphere. The outstanding catalytic performance of supported Ni–P and Fe–P catalysts provided an impressive liquid hydrocarbon yield between 63.37 and 79.65% with the highest green diesel selectivity of 62.64%. Decarbonylation (DCO) and decarboxylation (DCO₂) are the main pathways for the relative phosphide catalysts as presented by the high number of C_n−1 atoms (C₁₅ and C₁₇ hydrocarbons). In addition, metal phosphide/PFAC catalysts could achieve great potential application as a promising alternative catalyst for biofuel production via deoxygenation for large-scale operation owing to their excellent catalytic activity, simple preparation, and utilization of sustainable resources.

Palm oil deoxygenation over palm fiber activated biochar supported metal phosphide catalysts.

Electrochemical Reduction of CO2: A Review of Cobalt Based Catalysts for Carbon Dioxide Conversion to Fuels

Electrochemical CO2 reduction reaction (CO2RR) provides a promising approach to curbing harmful emissions contributing to global warming. However, several challenges hinder the commercialization of this technology, including high overpotentials, electrode instability, and low Faradic efficiencies of desirable products. Several materials have been developed to overcome these challenges. This mini-review discusses the recent performance of various cobalt (Co) electrocatalysts, including Co-single atom, Co-multi metals, Co-complexes, Co-based metal-organic frameworks (MOFs), Co-based covalent organic frameworks (COFs), Co-nitrides, and Co-oxides. These materials are reviewed with respect to their stability of facilitating CO2 conversion to valuable products, and a summary of the current literature is highlighted, along with future perspectives for the development of efficient CO2RR.

Trends and Prospects in UiO-66 Metal-Organic Framework for CO2 Capture, Separation, and Conversion

Among thousands of known metal-organic frameworks (MOFs), the University of Oslo's MOF (UiO-66) exhibits unique structure topology, chemical and thermal stability, and intriguing tunable properties, that have gained incredible research interest. This paper summarizes the structural advancement of UiO-66 and its role in CO₂ capture, separation, and transformation into chemicals. The first part of the review summarizes the fast-growing literature related to the CO₂ capture reported by UiO-66 during the past ten years. The second part provides an overview of various advancements in UiO-66 membranes in CO₂ purification. The third part describes the role of UiO-66 and its composites as catalysts for CO₂ conversion into useful products. Despite many achievements, significant challenges associated with UiO-66 are addressed, and future perspectives are comprehensively presented to forecast how UiO-66 might be used further for CO₂ management.