Abstract: An organic feedstock can be converted to one or more carbon allotropes by subjecting the organic feedstock to a high temperature of at least 4000 K for 60 seconds or less. The high temperature is provided by a thermal plasma generated between a pair of electrodes. In some examples, the organic feedstock includes particles of a biomass, organic polymer, and/or carbon black, and the one or more carbon allotropes are hard carbon, graphite, graphene, or carbon nanotubes.

Abstract: A catalytic structure has a substrate and a plurality of high-entropy alloy (HEA) nanoparticles. At least a surface layer of the substrate is formed of a metal oxide. The HEA nanoparticles can be formed on the surface layer. Each HEA nanoparticle can comprise a homogeneous mixture of at least four different elements forming a single-phase solid-solution alloy. The catalytic structures can be used to catalyze a chemical reaction, such as an ammonia oxidation reaction, an ammonia synthesis reaction, or an ammonia decomposition reaction.

Abstract: Degraded electrode material from a used battery can be recycled by subjecting to a thermal shock. The degraded electrode material can have impurities resulting from charge/discharge cycling of the battery. The thermal shock can have a temperature of at least 1000 K for a time period of 10 seconds or less, for example, less than or equal to 1 second. The thermal shock can also include a heating rate of at least 103 K/second preceding the time period and a cooling rate of at least 103 K/second following the time period. The subjecting to the thermal shock regenerate the electrode material, for example, by removing impurities from the electrode material and/or replenishing metal ions within the electrode material.

Abstract: A carbon material can comprise a porous scaffold of carbon fibrils and particles of carbon black attached to the carbon fibrils. The carbon material can be provided in an atmosphere of a gas comprising one or more organic compounds, for example, methane. The carbon material and the gas can be subjected to a temperature (e.g., 1700 K) that causes the organic compound(s) to undergo pyrolysis to form carbon and hydrogen. For example, the carbon material can be used as a Joule heating element to heat the material and the gas to the pyrolysis temperature. At least some of the formed carbon can be deposited on or within the carbon material. As a result, the carbon fibrils in the material can merge to form a carbonized matrix, and the carbon black particles can become embedded within the carbonized matrix.

Abstract: A structure can comprise one or multi-element compound (MEC) nanoparticles. Each MEC nanoparticle can have a plurality of sites comprising one or more elements. Each site can form a compound bond with at least one other site of the MEC nanoparticle. One or more of the compound bonds can comprise a covalent bond, an ionic bond, or a metallic bond. Each MEC nanoparticle can be formed of at least three different elements. For example, one or more MEC nanoparticles can be a multi-element oxide nanoparticle, a multi-element carbide nanoparticle, a multi-element intermetallic nanoparticle, or any other type of compound nanoparticle.