Search

The dominance of plastics in the packaging market is due to their low weight and thickness, which save transportation costs. However, their non-biodegradability poses a significant threat to the environment. Paper, on the other hand, is considered as a safer alternative due to its natural composition and biodegradability. The porous structure of paper limits its application in packaging, and its poor water resistance further restricts its use in humid environments. Therefore, lamination is a method useful tool to improve the barrier properties of paper. Additionally, the researchers are focusing on developing biodegradable and water-based coatings with anti-fat properties as a green alternative to plastic packaging. The impact of a new grease-resistant coating composed of starch, gelatin and sodium alginate on the mechanical properties of paper was investigated through tensile, tearing, and bursting strength tests. The results showed significant improvements in the mechanical properties of the coated paper sheets. Furthermore, the biodegradability test indicated that the paper samples coated with the new composition showed a 50% weight loss after one week of incubation in the soil, and after three weeks, they exhibited 100% weight loss, demonstrating their outstanding biodegradability.

Developing robust electrocatalysts based on nonprecious metals with high activity in the sluggish oxygen-evolution reaction (OER) is crucial for achieving large-scale hydrogen production. We present a novel approach to design a molecular iron-based hybrid composed of Fe3O4, Fe, and FeNi3 with a sphere-like structure deposited on a flaky substrate. Our optimized catalyst, denoted as Fe/Ni_450C, demonstrates superior electroactivity with a low overpotential of 307 mV, and a minimal Tafel slope of 42 mV dec−1. The material demonstrates ultra-high durability in a 425 h stability test, retaining 86.80% of initial potential at 10 mA cm−2, and exhibits outstanding resistance to high currents (450 mA). The ex situ XRD, XPS, and Mössbauer spectroscopy analyses shed light on the underlying mechanism. Utilizing low-temperature operational conditions, environmentally friendly substrates, cost-effectiveness, high abundance, and impressive stability at high current density collectively position our findings as a pivotal step toward practical applications in the industry associated with electrochemical water decomposition. [ABSTRACT FROM AUTHOR]

Recently, water oxidation or oxygen evolution reaction (OER) in electrocatalysis has attracted huge attention due to its prime role in water splitting, rechargeable metal–air batteries, and fuel cells. Here, we demonstrate a facile and scalable fabrication method of a rod-like structure composed of molybdenum disulfide and carbon (MoS2/C) from parent 2D MoS2. This novel composite, induced via the chemical vapor deposition (CVD) process, exhibits superior oxygen evolution performance (overpotential = 132 mV at 10 mA cm−2 and Tafel slope = 55.6 mV dec−1) in an alkaline medium. Additionally, stability tests of the obtained structures at 10 mA cm−2 during 10 h followed by 20 mA cm−2 during 5 h and 50 mA cm−2 during 2.5 h have been performed and clearly prove that MoS2/C can be successfully used as robust noble-metal-free electrocatalysts. The promoted activity of the rods is ascribed to the abundance of active surface (ECSA) of the catalyst induced due to the curvature effect during the reshaping of the composite from 2D precursor (MoS2) in the CVD process. Moreover, the presence of Fe species contributes to the observed excellent OER performance. FeOOH, Fe2O3, and Fe3O4 are known to possess favorable electrocatalytic properties, including high catalytic activity and stability, which facilitate the electrocatalytic reaction. Additionally, Fe-based species like Fe7C3 and FeMo2S5 offer synergistic effects with MoS2, leading to improved catalytic activity and durability due to their unique electronic structure and surface properties. Additionally, turnover frequency (TOF) (58 1/s at the current density of 10 mA cm−2), as a direct indicator of intrinsic activity, indicates the efficiency of this catalyst in OER. Based on ex situ analyzes (XPS, XRD, Raman) of the electrocatalyst the possible reaction mechanism is explored and discussed in great detail showing that MoS2, carbon, and iron oxide are the main active species of the reaction. [ABSTRACT FROM AUTHOR]

In this study, the catalytic performance of Ti 3 C 2 MXene materials in the reaction of α-pinene isomerization was demonstrated. The influence of etching agents (HF, HF/H 2 SO 4, and HF/HCl; weight ratios of mixed acids: 1 : 3, 1 : 4, and 1 : 5) on removing Al atoms from MAX phase, creation of an accordion-like structure typical for MXenes and catalytic activity of the produced samples have been revealed. The MXene HF obtained by MAX phase HF treatment exhibited the highest activity (conversion of α-pinene 74.65 mol%), while materials produced with the mixed acids (HF/H 2 SO 4 and HF/HCl) showed a significant reduction in the conversion of α-pinene (on average about 28-fold). However, these last samples displayed an increase of about 10 mol% in the selectivity to the most desirable product-camphene. The high activity of MXene HF is a result of a high concentration of acid sites (11.62 mmol g -1 ) - the concentration of acid sites in the samples obtained by MAX phase mixed acids treatment was about 2.5-5.5 times smaller. This work proposes possible mechanisms for the α-pinene isomerization reaction on the MXene HF and on the MXene HF/H 2 SO 4 X  :  Y and MXene HF/HCl X  :  Y in connection with their structure., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Recently, water oxidation or oxygen evolution reaction (OER) in electrocatalysis has attracted huge attention due to its prime role in water splitting, rechargeable metal-air batteries, and fuel cells. Here, we demonstrate a facile and scalable fabrication method of a rod-like structure composed of molybdenum disulfide and carbon (MoS 2 /C) from parent 2D MoS 2 . This novel composite, induced via the chemical vapor deposition (CVD) process, exhibits superior oxygen evolution performance (overpotential = 132 mV at 10 mA cm -2 and Tafel slope = 55.6 mV dec -1 ) in an alkaline medium. Additionally, stability tests of the obtained structures at 10 mA cm -2 during 10 h followed by 20 mA cm -2 during 5 h and 50 mA cm -2 during 2.5 h have been performed and clearly prove that MoS 2 /C can be successfully used as robust noble-metal-free electrocatalysts. The promoted activity of the rods is ascribed to the abundance of active surface (ECSA) of the catalyst induced due to the curvature effect during the reshaping of the composite from 2D precursor (MoS 2 ) in the CVD process. Moreover, the presence of Fe species contributes to the observed excellent OER performance. FeOOH, Fe 2 O 3 , and Fe 3 O 4 are known to possess favorable electrocatalytic properties, including high catalytic activity and stability, which facilitate the electrocatalytic reaction. Additionally, Fe-based species like Fe 7 C 3 and FeMo 2 S 5 offer synergistic effects with MoS 2 , leading to improved catalytic activity and durability due to their unique electronic structure and surface properties. Additionally, turnover frequency (TOF) (58 1/s at the current density of 10 mA cm -2 ), as a direct indicator of intrinsic activity, indicates the efficiency of this catalyst in OER. Based on ex situ analyzes (XPS, XRD, Raman) of the electrocatalyst the possible reaction mechanism is explored and discussed in great detail showing that MoS 2 , carbon, and iron oxide are the main active species of the reaction., (© 2023 IOP Publishing Ltd.)