Plasma Generating—Chemical Looping Catalyst Synthesis by Microwave Plasma Shock for Nitrogen Fixation from Air and Hydrogen Production from Water for Agriculture and Energy Technologies in Global Warming Prevention

Abstract

Simultaneous generation of plasma by microwave irradiation of perovskite or the spinel type of silica supported porous catalyst oxides and their reduction by nitrogen in the presence of oxygen is demonstrated. As a result of plasma generation in air, NOx generation is accompanied by the development of highly heterogeneous regions in terms of chemical and morphological variations within the catalyst. Regions of almost completely reduced catalyst are dispersed within the catalyst oxide, across micron-scale domains. The quantification of the catalyst heterogeneity and evaluation of catalyst structure are studied using Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and XRD. Plasma generating supported spinel catalysts are synthesized using the technique developed by the author (Catalysts; 2016; 6; 80) and BaTiO3 is used to exemplify perovskites. Silica supported catalyst systems are represented as M/Si = X (single catalysts) or as M(1)/M(2)/Si = X/Y/Z (binary catalysts) where M; M(1) M(2) = Cr; Mn; Fe; Co; Cu and X, Y, Z are the molar ratio of the catalysts and SiO2 support. Composite porous catalysts are synthesized using a mixture of Co and BaTiO3. In all the catalysts, structural heterogeneity manifests itself through defects, phase separation and increased porosity resulting in the creation of the high activity sites. The chemical heterogeneity results in reduced and oxidized domains and in very large changes in catalyst/support ratio. High electrical potential activity within BaTiO3 particles is observed through the formation of electrical treeing. Plasma generation starts as soon as the supported catalyst is synthesized. Two conditions for plasma generation are observed: Metal/Silica molar ratio should be > 1/2 and the resulting oxide should be spinel type; represented as MaOb (a = 3; b = 4 for single catalyst). Composite catalysts are represented as {M/Si = X}/BaTiO3 and obtained from the catalyst/silica precursor fluid with BaTiO3 particles which undergo fragmentation during microwave irradiation. Further irradiation causes plasma generation, NOx formation and lattice oxygen depletion. Partially reduced spinels are represented as MaOb–c. These reactions occur through a chemical looping process in micron-scale domains on the porous catalyst surface. Therefore; it is possible to scale-up this process to obtain NOx from MaOb for nitric acid production and H2 generation from MaOb–c by catalyst re-oxidized by water. Re-oxidation by CO2 delivers CO as fuel. These findings explain the mechanism of conversion of combustion gases (CO2 + N2) to CO and NOx via a chemical looping process. Mechanism of catalyst generation is proposed and the resulting structural inhomogeneity is characterized. Plasma generating catalysts also represent a new form of Radar Absorbing Material (RAM) for stealth and protection from radiation in which electromagnetic energy is dissipated by plasma generation and catalytic reactions. These catalytic RAMs can be expected to be more efficient in frequency independent microwave absorption.

Electrical and reaction performances of packed‐bed plasma reactors moderated with ferroelectric or dielectric materials

“…Finally, we should mention that apart from the right moderator choice in terms of their dielectric properties, the incorporation of classical catalysts in packed-bed plasma reactors and the design of new ones are current challenges that will enable increasing the energy efficiency and yield of the processes to make them competitive regarding classical catalysis processes. [52,55]…”

Accessing Low-Valent Titanium CCC-NHC Complexes: Toward Nitrogen Fixation

“…Ammonia produced through ANF is utilized in multiple large-scale industries apart from fertilizers; examples include: pharmaceuticals, explosives, plastic manufacturing, mining and metallurgy, production of nitric acid, et cetera [8]. Recently there is an increasing interest in using ammonia as the energy carrier of the future [17,18]. Further increase in conventional ANF will be ecologically undesirable in terms of carbon footprint, therefore new environmentally-friendly methods for ANF are required [19].…”

“…Improving the efficiency of ANF will lead to huge benefits on a world-wide scale. Multiple approaches ( Figure 1) have been undertaken to achieve this including: improvement of the H-B process conditions by exploring biological-mimics, homogeneous or heterogeneous catalysts designed to operate at milder conditions, semiconductor-based photocatalysis for nitrogen fixation, greener microwave plasma methods to synthesize ammonia and NOx, and hybrid systems between NNF and ANF such as development of synthetic rhizospheres (SRS), which helps intensify the NNF in plants via the development of a synthetic media [1,17,18,[20][21][22][23]. Binding of dinitrogen to a metal center depends on the formation of a stable reduced metal center, which can in turn reduce a dinitrogen molecule.…”

Ion-Enhanced Etching Characteristics of sp2-Rich Hydrogenated Amorphous Carbons in CF4 Plasmas and O2 Plasmas

“…Recently, carbons at the nanoscale attract great interest for a huge number of applications, such as transistor, field emission display, actuator, molecular wires/interconnect, transparent conducting film, supercapacitor, and catalyst [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Especially hydrogenated amorphous carbon (a-C:H) layers are widely used as a hard mask in semiconductor-device fabrication processes.…”