The methanation of CO and CO 2 present in coke oven gas was performed in a fixed-bed catalytic reactor at a reaction temperature between 200 and 400 °C. Different support materials, including SiO 2 , Al 2 O 3 , ZrO 2 , and CeO 2 , were doped with a different percentage of active metals using a standard impregnation and coprecipitation method. The catalysts were characterized using Brunauer−Emmett−Teller analysis, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programmed desorption techniques. The activity of all samples was tested in terms of the percentage of CO and CO 2 conversion and CH 4 selectivity. The results were analyzed on the basis of the difference in the catalytic performance at different active metal loadings and support materials. The effect of the catalytic support on the reducibility, morphology, and active metal dispersion was investigated. The ZrO 2 −CeO 2 -supported catalyst prepared under coprecipitation can attain 100% CO conversion at around 300 °C and ≥95% CO 2 conversion at 400 °C and has a CH 4 selectivity of 99%.

Photoelectrochemical (PEC) water splitting offers a sparkling and sustainable strategy for hydrogen generation, and significant research for enhancing the conversion efficiency of electrocatalysts is underway, since a huge number of publications have been reported in this field. Hence, it is urgent to write a comprehensive and updated review in order to highlight the latest progress in the design, fabrication, and modification of electrocatalysts for high-efficiency PEC water splitting. In this review, we describe the basic mechanism of PEC water splitting utilizing electrocatalysts in detail. Further, we highlighted the recent advancements in the design, fabrication, and modification of high-efficiency electrocatalysts for energy conversion. In addition, the catalysts' surface passivation, heterojunction constructions, defect engineering, and photovoltage and photocurrent enhancements are also highlighted.

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Controlling the selectivity in single-step conversion of syngas to single aromatic hydrocarbon to enhance CO utilization is a big challenge. By adapting the reaction coupling methodology, which allows the precise control of C–C coupling reaction, we obtained a high selectivity of ∼70% of a single product, tetramethylbenzene (TeMB), in hydrocarbons, at total CO conversion of 37%. This was enabled by the reaction of H2-deficient syngas over a composite catalyst of physically mixed nanosized ZnCr2O4 and H-ZSM-5. The H-ZSM-5 employed in this work appeared as a coffin shape with short straight channels [010] along the b-axis that exhibit low molecular-diffusion resistance, resulting in high selectivity of aromatics, particularly TeMB. Due to selective methanol formation and enhanced molecular diffusion, we observed an aromatic vacancy created inside H-ZSM-5 pores, which boosts the transformation of olefins into aromatics, thus making the aromatic cycle dominant in a dual-cycle mechanism and giving a high yield of aromatics and TeMB. Furthermore, no catalyst deactivation was observed within 600 h of reaction time using H2-deficient syngas. Therefore, by rejecting the need for extra H2 addition into the syngas-to-aromatics (STA) reaction system, direct conversion of H2-deficient syngas derived from coal/biomass into TeMB makes an attractive industrial process.

Supercapacitors (SCs) have received much interest due to their enhanced electrochemical performance, superior cycling life, excellent specific power, and fast charging–discharging rate. The energy density of SCs is comparable to batteries; however, their power density and cyclability are higher by several orders of magnitude relative to batteries, making them a flexible and compromising energy storage alternative, provided a proper design and efficient materials are used. This review emphasizes various types of SCs, such as electrochemical double-layer capacitors, hybrid supercapacitors, and pseudo-supercapacitors. Furthermore, various synthesis strategies, including sol-gel, electro-polymerization, hydrothermal, co-precipitation, chemical vapor deposition, direct coating, vacuum filtration, de-alloying, microwave auxiliary, in situ polymerization, electro-spinning, silar, carbonization, dipping, and drying methods, are discussed. Furthermore, various functionalizations of SC electrode materials are summarized. In addition to their potential applications, brief insights into the recent advances and associated problems are provided, along with conclusions. This review is a noteworthy addition because of its simplicity and conciseness with regard to SCs, which can be helpful for researchers who are not directly involved in electrochemical energy storage.