Candle Soot as a Novel Support for Nickel Nanoparticles in the Electrocatalytic Ethanol Oxidation.

The enhancement of carbon-supported components is a crucial factor in augmenting the interplay between carbon-supported and metal-active components in the utilization of catalysts for direct ethanol fuel cells (DEFCs). Here, we propose a strategy for designing a catalyst by modifying candle soot (CS) and loading nickel onto ordered carbon soot. The present study aimed to investigate the effect of the Ni nanoparticles content on the electrocatalytic performance of Ni-CS, ultimately leading to the identification of a maximum composition. The presence of an excessive quantity of nickel particles leads to a decrease in the number of active sites within the material, resulting in sluggishness of the electron transfer pathway. The electrocatalyst composed of nickel and carbon support, with a nickel content of 20 wt%, has demonstrated a noteworthy current activity of 18.43 mA/cm2, which is three times that of the electrocatalyst with a higher nickel content of 25 wt%. For example, the 20 wt% Ni-CS electrocatalytic activity was found to be good, and it was approximately four times higher than that of 20 wt% Ni-CB (nickel-carbon black). Moreover, the chronoamperometry (CA) test demonstrated a reduction in current activity of merely 65.80% for a 20 wt% Ni-CS electrocatalyst, indicating electrochemical stability. In addition, this demonstrates the great potential of candle soot with Ni nanoparticles to be used as a catalyst in practical applications.

A highly-selective layer-by-layer membrane modified with polyethylenimine and graphene oxide for vanadium redox flow battery.

A selective composite membrane for vanadium redox flow battery (VRFB) was successfully prepared by layer-by-layer (LbL) technique using a perfluorosulfonic sulfonic acid or Nafion 117 (N117). The composite membrane referred as N117-(PEI/GO)n, was obtained by depositing alternating layers of positively charged polyethylenimine (PEI) and negatively charged graphene oxide (GO) as polyelectrolytes. The physicochemical properties and performance of the pristine and composite membranes were investigated. The membrane showed an enhancement in proton conductivity and simultaneously exhibited a notable 90% reduction in vanadium permeability. This, in turn, results in a well-balanced ratio of proton conductivity to vanadium permeability, leading to high selectivity. The highest selectivity of the LbL membranes was found to be 19.2 × 104 S.min/cm3, which is 13 times higher than the N117 membrane (n = 0). This was translated into an improvement in the battery performance, with the n = 1 membrane showing a 4-6% improvement in coulombic efficiency and a 7-15% improvement in voltage efficiency at current densities ranging from 40 to 80 mA/cm2. Furthermore, the membrane displays stable operation over a long-term stability at around 88% at a current density of 40 mA/cm2, making it an attractive option for VRFB applications using the LbL technique. The use of PEI/GO bilayers maintains high proton conductivity and VE of the battery, opening up possibilities for further optimization and improvement of VRFBs.

An innovative N117-(PEI/GO)n layer-by-layer membrane prepared for vanadium redox flow battery improved the balance between the proton conductivity and vanadium permeability, yielding a remarkable selectivity of 19.2 × 10⁴ S.min/cm³.

Enhanced simultaneous degradation of simulated dyes using ZnO/GCN heterojunction photocatalyst.

The scarcity of water leads to research nowadays to focus on techniques for treating wastewater. Photocatalysis emerged as a technique of interest due to its nature of friendliness. It utilizes light and catalyst to degrade the pollutants. One of the popular catalysts to be used is zinc oxide (ZnO), but its usage is limited due to the high recombination rate of electron-hole pair. Herein, in this study, ZnO is modified with graphitic carbon nitride (GCN), and the GCN loading amount was varied to study the impact on photocatalytic degradation of mixed dye solution. To the best of our knowledge, this is the first work that reports on the degradation of mixed dye solution using modified ZnO with GCN. Structural analysis showed that GCN is present in the composites which proves the success of the modification. Photocatalytic activity revealed that the composite with 5 wt% loading of GCN showed the best activity at a catalyst dosage of 1 g/L with degradation rates of 0.0285, 0.0365, 0.0869, and 0.1758 min-1 for methyl red, methyl orange, rhodamine B, and methylene blue dyes, respectively. This observation is expected due to the formation of heterojunction between ZnO and GCN which creates a synergistic effect and thus led to an improvement in the photocatalytic activity. Based on these results, ZnO modified with GCN has a good potential to be used in the treatment of textile wastewater which consists of various dye mixtures.

Improvements in the stability of biodiesel fuels: recent progress and challenges.

Fewer fossil fuel deposits, price volatility, and environmental concerns have intensified biofuel-based studies. Saccharification, gasification, and pyrolysis are some of the potential methods of producing carbohydrate-based fuels, while lipid extraction is the preferred method of producing biodiesel and green diesel. Over the years, multiple studies have attempted to identify an ideal catalyst as well as optimize the abovementioned methods to produce higher yields at a lower cost. Therefore, this present study comprehensively examined the factors affecting biodiesel stability. Firstly, isomerization, which is typically used to reduce unsaturated fatty acid content, was found to improve oxidative stability as well as maintain and improve cold flow properties. Meanwhile, polymers, surfactants, or small molecules with low melting points were found to improve the cold flow properties of biodiesel. Meanwhile, transesterification with an enzyme could be used to remove monoacylglycerols from oil feedstock. Furthermore, combining two natural antioxidants could potentially slow lipid oxidation if stainless steel, carbon steel, or aluminum are used as biodiesel storage materials. This present review also recommends combining green diesel and biodiesel to improve stability. Furthermore, green diesel can be co-produced at oil refineries that are more selective and have a limited supply of hydrogen. Lastly, next-generation farming should be examined to avoid competing interests in food and energy as well as to improve agricultural efficiency.

Magnetite-based catalysts for wastewater treatment.

The increasing number and concentration of organic pollutants in water stream could become a serious threat in the near future. Magnetite has the potential to degrade pollutants via photocatalysis with a convenient separation process. This study discusses in detail the control size and morphology of magnetite nanoparticles, and their composites with co-precipitation, hydrothermal, sol-gel, and electrochemical route. Further photocatalytic enhancement with the addition of metal and porous support was proposed. This paper also discussed the technology to extend the lifetime of recombination through an in-depth explanation of charge transfer. The possibility to use waste materials as catalyst support was also elucidated. However, magnetite-based photocatalysts still require many improvements to meet commercialization criteria.