Mechanochemical synthesis of bifunctional Co–N–C electrocatalysts.

Efficient and sustainable synthesis of performant metal/nitrogen-doped carbon (M–N–C) catalysts for oxygen reduction and evolution reactions (ORR/OER) is vital for the global switch to green energy technologies–fuel cells and metal–air batteries. This study reports a solid-phase template-assisted mechanosynthesis of Fe–N–C, featuring low-cost and sustainable FeCl3, 2,4,6-tri­(2-pyridyl)-1,3,5-triazine (TPTZ), and NaCl. A NaCl-templated Fe-TPTZ metal–organic material was formed using facile liquid-assisted grinding/compression. With NaCl, the Fe-TPTZ template-induced stability allows for a rapid, thus, energy-efficient pyrolysis. Among the produced materials, 3D-FeNC-LAG exhibits remarkable performance in ORR (E 1/2 = 0.85 V and E onset = 1.00 V), OER (E j=10 = 1.73 V), and in the zinc–air battery test (power density of 139 mW cm–2). The multilayer stream mapping (MSM) framework is presented as a tool for creating a sustainability assessment protocol for the catalyst production process. MSM employs time, cost, resource, and energy efficiency as technoeconomic sustainability metrics to assess the potential upstream impact. MSM analysis shows that the 3D-FeNC-LAG synthesis exhibits 90% overall process efficiency and 97.67% cost efficiency. The proposed synthetic protocol requires 2 times less processing time and 3 times less energy without compromising the catalyst efficiency, superior to the most advanced methods.

Water is one of the most important substances on our planet1. It is ubiquitous in its solid, liquid and vaporous states and all known biological systems depend on its unique chemical and physical properties. Moreover, many materials exist as water adducts, chief among which are crystal hydrates (a specific class of inclusion compound), which usually retain water indefinitely at subambient temperatures2. We describe a porous organic crystal that readily and reversibly adsorbs water into 1-nm-wide channels at more than 55% relative humidity. The water uptake/release is chromogenic, thus providing a convenient visual indication of the hydration state of the crystal over a wide temperature range. The complementary techniques of X-ray diffraction, optical microscopy, differential scanning calorimetry and molecular simulations were used to establish that the nanoconfined water is in a state of flux above −70 °C, thus allowing low-temperature dehydration to occur. We were able to determine the kinetics of dehydration over a wide temperature range, including well below 0 °C which, owing to the presence of atmospheric moisture, is usually challenging to accomplish. This discovery unlocks opportunities for designing materials that capture/release water over a range of temperatures that extend well below the freezing point of bulk water.

No abstract

ISRA (India) = 4.971 ISI (Dubai, UAE) = 0.829 GIF (Australia) = 0.564 JIF = 1.500 SIS (USA) = 0.912 РИНЦ (Russia) = 0.126 ESJI (KZ) = 8.997 SJIF (Morocco) = 5.667 ICV (Poland) = 6.630 PIF (India) = 1.940 IBI (India) = 4.260 OAJI (USA) =

Today high-cost Pt-group noble-metal electrocatalysts are still widely applied to effectively overcome the ORR/OER overpotentials.High cost and low abundance alongside poor stability make it necessary to find a replacement for noble-metal-based catalysts to commercialize advanced energy systems successfully. Extensive research of this topic by scientific society resulted in developing various non-noble-metal-based catalysts. Among the recently developed materials, M-N-C catalysts demonstrate great catalytic activity and extraordinary stability, low cost, and a wide variety of sources, making them excellent candidates for replacing Pt-based catalysts.Currently, the most commonly used method for producing M-N-C type catalysts is the carbonization of the precursor material or wet-impregnation of the precursor on carbon support with subsequent carbonization. Additionally, currently available processes often do not meet the current environmental requirements, and the majority of methods are energy-demanding.Here we present a new concept of a facile green method of large-scale synthesis of M-N-C type catalysts with bifunctional electroactivity towards oxygen reduction and evolution reactions.