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Dry reforming of methane (DRM) emerged as a green alternative to utilize major greenhouse gases (GHG's) and produce syngas. However, the main limitations of DRM are sintering and coking of catalyst. In recent decade the Ni-based catalysts has been meticulously studied for DRM reaction since noble metal-based catalysts can't be commercialized due to economic constraints. The catalyst support, synthesis techniques, effect of promoters can significantly affect the catalyst performance. Mesoporous silica (MS) supported catalysts emerged as a promising material due to their enhanced applications in catalysts with significantly high surface areas, thermal stability, and easy availability. Till date no separate study has been carried out focusing the MS as catalyst support for DRM. This comprehensive review highlights the recent advances in MS supported catalysts for DRM. Further, it focuses on reaction mechanism, reaction kinetics, thermodynamics, effect of catalyst support, synthesis route and effect of promoters on DRM performance. [Display omitted] • The performance of mesoporous silicas (MS) as Ni support in DRM was reviewed. • Unique features of MS types and how they affect support property was discussed. • Thorough appraisal of promoter and preparation route effects on Ni-MS catalysts. • Comprehensive overview of DRM thermodynamics, kinetics, and reaction mechanisms. [ABSTRACT FROM AUTHOR]

Catalytic fast pyrolysis of cassava stalks has been intriguing as a promising, feasible chemical refinery method in terms of waste-to-energy conversion from cassava cultivation. This study aims to determine the synergetic influence of Mo and Co on Ni catalysts (Ni, Ni–Mo, and Ni–Co) prepared via ultrasonic-assisted incipient wetness impregnation method for catalytic pyrolysis vapor upgrading. The results indicated that Co and Mo enhance the reducibility of NiO and promote weak-to-medium acidity, thereby enhancing Ni's performance. Mono-Ni favors cracking deoxygenation, whereas oxophilicity promoters particularly enhance the oxygen absorbability efficiency to selective deoxygenated production. A fine Ni dispersion on CoNi/SiO 2 catalyst was observed to positively affect the production of monoaromatic hydrocarbons (46.10 %), in contrast to those without promoters (21.63 %). This is attributed to an optimal Ni-metallic distribution with a small crystal size of 7.01 nm and a high surface area of 342.6 m2 g−1, highlighting the effectiveness of the promoter-assisted Ni catalyst. Additionally, a high yield of H 2 (66.9 %) in non-condensable gas was recorded at 550 °C. The study suggests that a simplified approach to developing Ni-based catalysts could enhance the eco-friendliness of commercial catalysts, thereby facilitating the scale-up of biomass pyrolysis applications. [Display omitted] • Co, Mo boosts Ni reducibility, reduces the Ni particle. • Co, Mo raises weak-to-medium acidity in Ni/SiO 2. • Enhanced selective of BTX with the presence of the Co, Mo. • Syngas produced by reforming methane at elevated temperature. [ABSTRACT FROM AUTHOR]

The process parameters for dry reforming of methane (DRM) over Ni–W/Al 2 O 3 –MgO catalyst are optimized using response surface methodology (RSM). The Ni–W bimetallic catalyst is synthesized by co-precipitation method followed by impregnation. The catalysts are characterized by BET, XRD, FESEM, EDX and TEM; to study physicochemical properties, morphology, composition, crystallite size and deposited carbon. The effect of process parameters, i.e., reaction temperature (600oC–800 °C) and feed gas ratio (0.5–1.5) on the CH 4 , CO 2 conversions and syngas ratio are studied. A temperature of 777.29 °C with CH 4 : CO 2 of 1.11 at GHSV of 36,000 cm3gm.cat−1h−1, delivered the CH 4 and CO 2 conversions of 87.6% and 93.3%, respectively along with H 2 :CO of 1. The predicted process parameters were verified through actual experimental analysis at the optimized conditions, and results agreed with CCD of the RSM model with insignificant error. The MWCNT formed during DRM avoided catalyst deactivation and delivered stable performance over 12 h of reaction test at the optimized conditions. [Display omitted] • Ni–W bimetallic catalyst has been synthesized and studied for DRM. • Reaction temperature is more dominant on conversion of reactants than feed ratio. • Optimal conditions for Ni–W catalyst for DRM: T = 777.29 °C and CH 4 :CO 2 = 1.11. • Optimal conversion obtained for CH 4 = 85.5% and CO 2 = 90.1% with H 2 :CO = 0.96. [ABSTRACT FROM AUTHOR]

During the last few decades, the global energy requirement is soaring significantly due to the rise of global population and economic development. This resulted in colossal release of CO 2 and CH 4, emissions into the atmosphere referred as greenhouse gases (GHGs), which poses a detrimental effects for the environment. One of the sustainable solutions to curb emissions of GHGs into the atmosphere is efficient utilization of syngas in order to produce useful chemicals and fuels. A comprehensive review is presented to highlight the capability of Ni-based catalysts in methane reforming through the application of both steam and dry routes referred to as bi-reforming of methane (BRM). Ni-based catalysts were found to support favorable reaction activity as they are cheaper than many exorbitant catalysts. The metal used for catalyst support exhibits higher stability and thermal resistance with improved resistance to coke formation. This review entails recent progresses in the development of Ni-based catalysts along with physical and kinetic aspects of the BRM process. • Recent trend in bi reforming of methane (BRM) using Ni-based catalysts. • Comprehensive review on role and performance of Ni-based catalyst for BRM. • Modification of Ni-based catalyst to enhance activity, conversion and yield of syngas. • Future outlook of Ni-based catalyst for BRM. [ABSTRACT FROM AUTHOR]

• Recent trends in dry reforming of methane (DRM) using Ni-based catalysts. • Morphology of support plays a key role in the performance and stability of the catalyst. • Complex (bi-and tri-metallic) Ni-based catalysts showed enhanced performance for DRM. • Dendritic fibrous nanocatalysts (DFN) can be a potential substitute for conventional catalysts. • DFT modeling of complex catalysts before the synthesis can be considered in future work. The emission of greenhouse gases (GHGs), e.g. CO 2 and CH 4 into the atmosphere leads to an undesirable effect on climate change. One viable solution is to convert these two GHGs into valuable syngas via catalytic dry reforming of methane (DRM). Due to low-cost, feasibility, good catalytic activity, Ni-based catalysts have been used and tested extensively for DRM. However, the main limitation is the catalyst deactivation which occurs due to carbon formation and sintering of catalyst at high temperatures. This review aimed to provide up-to-date summary on the DRM process, including aspects of composite (bimetallic and trimetallic) catalysts and also the influence of doping metal on the catalysts. Furthermore, the metal support studies with the reaction mechanisms and kinetic studies, the latest catalyst configuration and their preparation methods have been highlighted. Therefore, the impending research focuses on composite catalysts and its density functional theory modelling for DRM to design an ideal catalyst. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future. [ABSTRACT FROM AUTHOR]

Dry reforming of acetic acid (DRA) was first-time investigated on 10%Ni/Al 2 O 3 at varied temperatures within 923–973 K employing several CO 2 :CH 3 COOH ratios of 1.5:2; 1:1; and 2:1. Depending on NiO particle size and location on support surface or inside the porous support structure, the H 2 reduction of NiO phase to active metallic Ni0 form was evidenced at different reduction temperatures within 550–950 K and the estimated degree of reduction was about 73.68%. Weak, medium, and strong basic centres were evidenced on 10%Ni/Al 2 O 3 via CO 2 desorption measurement. Increasing DRA temperature improved both CH 3 COOH and CO 2 conversions with the corresponding apparent activation energy of 100.71 and 58.50 kJ mol−1. As CO 2 partial pressure was increased from 0 to 40 kPa, the initial CH 3 COOH conversion was noticeably enhanced from 30.5% to 97.8% whilst H 2 /CO ratio always remained less than unity (0.73–0.77). Notably, DRA was a two-step process and barely negligible CH 4 intermediate product was evidenced since it was promptly reformed by CO 2 into syngas. The Ni0 active form was not susceptible to oxidation during DRA and carbon deposited on spent catalyst surface was heterogeneous in nature with the evident co-existence of amorphous and graphitic carbons. [Display omitted] • For the first time, acetic acid dry reforming was conducted for H 2 production. • Apparent activation energy for CH 3 COOH conversion was about 100.71 kJ mol−1. • H 2 /CO ratio was 0.73–0.77 preferred for downstream Fischer-Tropsch synthesis. • Filamentous and graphitic carbons co-existed on spent catalyst surface. [ABSTRACT FROM AUTHOR]

The use of nanostructure materials as heterogeneous catalysts in the synthesis of organic compounds have been receiving more attention in the rapid developing area of nanotechnology. In this review, we mainly focused on our own work on the synthesis of hybrid palladium–iron oxide nanoparticles. We discuss the synthesis of Pd–Fe3O4—both morphology-controlled synthesis of Pd–Fe3O4 and transition metal-loaded Pd–Fe3O4—as well as its application in various C–C coupling reactions. In the case of rose-like Pd–Fe3O4 hybrid nanoparticles, thermal decomposition can be used instead of oxidants or reductants, and morphology can be easily controlled. We have developed a method for the synthesis of nanoparticles that is facile and eco-friendly. The catalyst was recyclable for up to five continual cycles without significant loss of catalytic activity and may provide a great platform as a catalyst for other organic reactions in the near future. [ABSTRACT FROM AUTHOR]

The rising world population and its corresponding energy demands pose a considerable burden on natural energy sources. The exploitation of fossil fuels at such an alarming rate blurs the goals of sustainable development and controlling global warming as pledged during the Paris Agreement. Due to the detrimental effects of exhausts from conventional diesel fuel on the environment, biodiesel has earned significant importance during the last decade. Biodiesel is produced from different feedstocks such as neem oil, palm oil, waste frying oil, vegetable oil, animal fat, microbial oil, etc. These feedstocks react with acidic, alkaline, enzymic, homogeneous, heterogeneous, and hybrid Deep Eutectic Solvents (DES) catalysts, along with monohydric alcohol via transesterification reaction. The flexibility in its feedstock and the type of catalysts used, production cost, biodegradable and renewable nature makes it a promising alternative fuel than conventional diesel. The selection of apt feedstock and catalyst is the challenging task and governing factor of economic biodiesel production. Green solvents such as DES have high thermal stability and low volatility and can address the economic and green production issues significantly as compared to conventional alkali and acid catalysts. This review bridges the gap between the selection of feedstock and optimal catalyst for the respective feedstock. The exploration of DES fills the gap by attributing to 3Rs (i.e., recyclability, recovery, and reusability). This review highlights the contemporary trends and prospects in the selection of the feedstocks, synthesis routes, and catalysts for the transesterification reactions for biodiesel production. [Display omitted] • The article highlights the feedstocks' role, synthesis routes, and catalysts for biodiesel production. • The various factors which affect biodiesel production have been discussed. • The role of green solvents (DESs) as a catalyst for biodiesel production has been reviewed. • Results have shown that DESs have a great potential to produce cleaner biodiesel. • The article suggests cleaner pathways for various catalysts and feedstock for biodiesel production. [ABSTRACT FROM AUTHOR]