Inert

About: Inert is a research topic. Over the lifetime, 3521 publications have been published within this topic receiving 29099 citations.

High-performance artificial nitrogen fixation at ambient conditions using a metal-free electrocatalyst

Abstract: Conversion of naturally abundant nitrogen to ammonia is a key (bio)chemical process to sustain life and represents a major challenge in chemistry and biology. Electrochemical reduction is emerging as a sustainable strategy for artificial nitrogen fixation at ambient conditions by tackling the hydrogen- and energy-intensive operations of the Haber–Bosch process. However, it is severely challenged by nitrogen activation and requires efficient catalysts for the nitrogen reduction reaction. Here we report that a boron carbide nanosheet acts as a metal-free catalyst for high-performance electrochemical nitrogen-to-ammonia fixation at ambient conditions. The catalyst can achieve a high ammonia yield of 26.57 μg h–1 mg–1cat. and a fairly high Faradaic efficiency of 15.95% at –0.75 V versus reversible hydrogen electrode, placing it among the most active aqueous-based nitrogen reduction reaction electrocatalysts. Notably, it also shows high electrochemical stability and excellent selectivity. The catalytic mechanism is assessed using density functional theory calculations. Electrochemical reduction of nitrogen is a promising route to industrial-scale nitrogen fixation at ambient conditions, but is challenged by activation of inert nitrogen. Here the authors report a metal-free catalyst that selectively reduces nitrogen to ammonia with high efficiency and stability.

Multi-stage process for producing polyethylene

Abstract: The invention concerns a multi-stage process for producing polyethylene having a bimodal and/or broad molecular weight distributioin in the presence of an ethylene polymerizing catalyst system in a multistep reaction sequence, in which the first reaction step is a liquid phase polymerization step and the second reaction step is formed by one or more gas-phase polymerization steps. According to the process of the invention in the first reaction step ethylene is polymerized in a loop reactor (10) in an inert low-boiling hydrocarbon medium the residence time being at least 10 minutes, reaction mixture is discharged from the loop reactor (10) and at least a substantial part of the inert hydrocarbon mixture is separated and the polymere is transferred into one or more gas-phase reactors (30), where the polymerization is completed in the presence of ethylene and optionally hydrogen and a comonomer. As an inert hydrocarbon medium in the loop reactor (10) propane can be used and the polymerization can be carried out also so that the mixture of inert hydrocarbon, monomer, hydrogen and optional comonomer is under supercritical conditions.

Gaseous process and apparatus for removing films from substrates

Abstract: A process for removing at least a portion of a film from a substrate, such as a wafer of silicon or other similar materials, the film on the substrate typically being an oxide film, maintaining the atmosphere embracing the substrate at near room temperature and at near normal atmospheric pressure, flowing dry inert diluent gas over the substrate, introducing a flow of reactive gas, preferably an anhydrous hydrogen halide gas, namely anhydrous hydrogen flouride gas, for typically 5 to 30 seconds over the substrate and film to cause the removal of portions of the film, flowing water vapor laden inert gas, preferably nitrogen, over the substrate and film from a time prior to commencing flow of the reactive gas until flow of the reactive gas is terminated. In the case of non-hygroscopic film on the substrate, the flow of water vapor continues during the flow of the reactive gas and is terminated shortly after the termination of the flow of reactive gas. In the case of hygroscopic film, the flow of water vapor is discontinued prior to the start of flow of the reactive gas. In carrying out the process, a process chamber is needed to confine the substrate and have a vent, which though restricted, continuously open to the atmosphere.

Plasma treatment of hafnium-containing materials

Abstract: In one embodiment, a method for forming a dielectric material is provided which includes exposing a substrate sequentially to a metal-containing precursor and an oxidizing gas to form metal oxide (e.g., HfO x ) during an ALD process and subsequently exposing the substrate to an inert plasma process and a thermal annealing process. Generally, the metal oxide contains hafnium, tantalum, titanium, aluminum, zirconium, lanthanum or combinations thereof. In one example, the inert plasma process contains argon and is free of nitrogen, while the thermal annealing process contains oxygen. In another example, an ALD process to form a metal oxide includes exposing the substrate sequentially to a metal precursor and an oxidizing gas containing water vapor formed by a catalytic water vapor generator. In an alternative embodiment, a method for forming a dielectric material is provide which includes exposing a substrate to a deposition process to form a metal oxide layer and subsequently exposing the substrate to a nitridation plasma process and a thermal annealing process to form metal oxynitride (e.g., HfO x N y ).