Abstract: A method of ammonia synthesis is described that includes contacting a nitrogen gas-containing plasma with an aqueous solution, thereby forming ammonia from the nitrogen gas and water. The nitrogen gas-containing plasma is present in an electrochemical cell. The electrochemical cell includes a container including an acidic liquid electrolyte. The electrochemical cell also includes a source of nitrogen gas, a metal electrode at least partially immersed in the electrolyte, a metal tube electrode spaced apart from a surface of the electrolyte by a predetermined spacing. The electrochemical cell is configured to provide a plasma spanning the predetermined space from the metal tube electrode to contact the surface of the electrolyte when power is applied to the metal tube electrode.

Abstract: A method of ammonia synthesis is described that includes contacting a nitrogen gas-containing plasma with an aqueous solution, thereby forming ammonia from the nitrogen gas and water. The nitrogen gas-containing plasma is present in an electrochemical cell. The electrochemical cell includes a container including an acidic liquid electrolyte. The electrochemical cell also includes a source of nitrogen gas, a metal electrode at least partially immersed in the electrolyte, a metal tube electrode spaced apart from a surface of the electrolyte by a predetermined spacing. The electrochemical cell is configured to provide a plasma spanning the predetermined space from the metal tube electrode to contact the surface of the electrolyte when power is applied to the metal tube electrode.

Abstract: A method for directly writing metal traces on a wide range of substrate materials is disclosed. The method includes writing a pattern of particle-free metal-salt-based ink on the substrate followed by a plasma-based treatment to remove the non-metallic components of the ink and decompose its metal salt into pure metal. The ink is based on a multi-part solvent whose components differ in at least one of evaporation rate, surface tension, and viscosity, which improves the manner in which the ink is converted into its metal constituent via the plasma treatment. In some embodiments, a microplasma is used for post-treatment of the deposited ink, where the plasma properties are controlled to provide different material properties, such as porosity and effective resistivity, in different regions of the metal pattern.

Abstract: A method of ammonia synthesis is described that includes contacting a nitrogen gas-containing plasma with an aqueous solution, thereby forming ammonia from the nitrogen gas and water. The nitrogen gas-containing plasma is present in an electrochemical cell. The electrochemical cell includes a container including an acidic liquid electrolyte. The electrochemical cell also includes a source of nitrogen gas, a metal electrode at least partially immersed in the electrolyte, a metal tube electrode spaced apart from a surface of the electrolyte by a predetermined spacing. The electrochemical cell is configured to provide a plasma spanning the predetermined space from the metal tube electrode to contact the surface of the electrolyte when power is applied to the metal tube electrode.

Abstract: A microplasma sputter deposition system suitable for directly writing two-dimensional and three-dimensional structures on a substrate is disclosed. Deposition systems in accordance with the present invention include a magnetic-field generator that provides a magnetic field that is aligned with the arrangement of an anode and a wire target. This results in a plasma discharge within a region between a wire target and an anode that is substantially a uniform sheet, which gives rise to the deposition of material on the substrate in highly uniform and radially symmetric fashion.

Abstract: A method for directly writing metal traces on a wide range of substrate materials is disclosed. The method includes writing a pattern of particle-free metal-salt-based ink on the substrate followed by a plasma-based treatment to remove the non-metallic components of the ink and decompose its metal salt into pure metal. The ink is based on a multi-part solvent whose components differ in at least one of evaporation rate, surface tension, and viscosity, which improves the manner in which the ink is converted into its metal constituent via the plasma treatment. In some embodiments, a microplasma is used for post-treatment of the deposited ink, where the plasma properties are controlled to provide different material properties, such as porosity and effective resistivity, in different regions of the metal pattern.

Abstract: A method of forming nanoscale diamond particles comprises providing C2 and CH radicals at a low pressure, and nucleating the C2 and CH radicals to form carbon nanoparticles comprising a diamond phase and a non-diamond phase. The method further comprises removing at least a portion of the non-diamond phase in flight during the nucleation of the C2 and CH radicals to form a carbon powder comprising a plurality of nanoscale diamond particles.

Abstract: A microplasma sputter deposition system suitable for directly writing two-dimensional and three-dimensional structures on a substrate is disclosed. Deposition systems in accordance with the present invention include a magnetic-field generator that provides a magnetic field that is aligned with the arrangement of an anode and a wire target. This results in a plasma discharge within a region between a wire target and an anode that is substantially a uniform sheet, which gives rise to the deposition of material on the substrate in highly uniform and radially symmetric fashion.

Abstract: A method of forming nanoscale diamond particles comprises providing C2 and CH radicals at a low pressure, and nucleating the C2 and CH radicals to form carbon nanoparticles comprising a diamond phase and a non-diamond phase. The method further comprises removing at least a portion of the non-diamond phase in flight during the nucleation of the C2 and CH radicals to form a carbon powder comprising a plurality of nanoscale diamond particles.

Abstract: A method for synthesizing carbon nanotubes having a narrow distribution of diameter and/or chirality is presented. The method comprises providing catalyst particles to a reactor for synthesizing the carbon nanotubes, wherein the catalyst particles are characterized by a narrow distribution of catalyst-particle diameters and a narrow distribution of catalyst-particle compositions. Preferably, the catalyst particles are characterized by a mean catalyst-particle diameter of 2.6 nm or less and a composition of NixFe1-x, wherein x is less than or equal to 0.5.

Abstract: An electrochemical cell includes a container at atmospheric pressure comprising a liquid electrolyte and a first electrode at least partially immersed in the electrolyte. A plasma source is spaced apart from a surface of the electrolyte by a predetermined spacing, and a plasma spans the predetermined spacing to contact the surface of the electrolyte. A method of operating the electrochemical cell entails providing a first electrode at least partially immersed in a liquid electrolyte and producing a plasma in contact with a surface of the electrolyte at atmospheric pressure. The plasma acts as a second electrode, and a current is generated through the electrolyte. Electrochemical reactions involving at least the second electrode are initiated in the electrolyte.

Abstract: A method for synthesizing carbon nanotubes having a narrow distribution of diameter and/or chirality is presented. The method comprises providing catalyst particles to a reactor for synthesizing the carbon nanotubes, wherein the catalyst particles are characterized by a narrow distribution of catalyst-particle diameters and a narrow distribution of catalyst-particle compositions. Preferably, the catalyst particles are characterized by a mean catalyst-particle diameter of 2.6 nm or less and a composition of NixFe1-x, wherein x is less than or equal to 0.5.

Abstract: An electrochemical cell includes a container at atmospheric pressure comprising a liquid electrolyte and a first electrode at least partially immersed in the electrolyte. A plasma source is spaced apart from a surface of the electrolyte by a predetermined spacing, and a plasma spans the predetermined spacing to contact the surface of the electrolyte. A method of operating the electrochemical cell entails providing a first electrode at least partially immersed in a liquid electrolyte and producing a plasma in contact with a surface of the electrolyte at atmospheric pressure. The plasma acts as a second electrode, and a current is generated through the electrolyte. Electrochemical reactions involving at least the second electrode are initiated in the electrolyte.

Abstract: An apparatus for producing features having a surface roughness in a substrate includes, according to one embodiment, a conductive first electrode disposed in opposition to a conductive second electrode, where the first and second electrodes are spaced apart from each other by a distance adapted for generating a microplasma therebetween. The second electrode is a substrate, and the first electrode and the substrate are configured for relative motion in at least two opposing directions. A feature comprising a surface roughness of greater than about 10 nm is formed in the substrate when the microplasma is generated. Preferably the feature has a width of about 300 nm or less. A plurality of the features (e.g., an ordered array of features) may be produced in the substrate, if desired. The substrate may be a silver-coated glass substrate used for surface-enhanced Raman scattering (SERS) analysis of biochemical molecules.

Abstract: A system and method for making nanoparticles. The system includes a first cathode including a first metal tube associated with a first end and a second end, a first anode including a second metal tube associated with a third end and a fourth end, and a first container including a first gas inlet. The first end and the third end are located inside the first container. The first end and the third end are separated by a first gap, the first metal tube is configured to allow a first gas to flow from the second end to the first end, and the first container is configured to allow a second gas to flow from the first gas inlet into the second metal tube through at least a first part of the first gap.

Abstract: An apparatus and method for converting methane to methanol by partial oxidation comprises a source of methane, a source of oxygen, and a capillary tube having an outflow end and an inflow end communicating with the sources of methane and oxygen. An anode is positioned proximate to but spaced from the capillary tube. A voltage source negatively biases the capillary tube relative to the anode. A plasma jet flows from the outflow end of the capillary tube. The methane partially oxidizes into methanol in a reaction zone in the plasma jet. A collector receives the methanol in the plasma jet for subsequent condensation, separation and purification.

Abstract: A method of operation and an apparatus for providing excimer radiation is performed in and comprised of a plurality of microdischarge stages respectively. Each stage is comprised of a cathode element and anode-like element through which elements a selected gas flows. The microdischarge stages of the plurality are serially communicated with each other such that the gas flows in succession through each stage of the plurality. A power supply is coupled to each stage for providing a correspondingly selected plasma voltage to each stage to initiate and/or maintain an excimer plasma within each stage.

Abstract: An apparatus and method for converting methane to methanol by partial oxidation comprises a source of methane, a source of oxygen, and a capillary tube having an outflow end and an inflow end communicating with the sources of methane and oxygen. An anode is positioned proximate to but spaced from the capillary tube. A voltage source negatively biases the capillary tube relative to the anode. A plasma jet flows from the outflow end of the capillary tube. The methane partially oxidizes into methanol in a reaction zone in the plasma jet. A collector receives the methanol in the plasma jet for subsequent condensation, separation and purification.