News By Tag
News By Place
QED Radiation: The Holy Grail of natural gas catalysis
The remarkable conversion of natural gas to ethylene thought catalyzed by the nanoconfinement of single iron sites in a silica matrix is superseded by QED radiation in a flow reactor from a nanoscale iron coating on a heated silica substrate
By: QED Radiations
Since the 1980's, the oxidative catalysis of natural gas or methane to ethylene, aromatics, and hydrogen including propylene, benzene, toluene, and naphthalene has required oxygen at high temperatures > 1073 K. Beyond the low 50% carbon utilization efficiency, oxygen leads to the over oxidation product of CO2 which is not environmentally friendly. Today, many catalysts to avoid the oxidative conversion of natural gas have been proposed, but none are yet economically available.
Indeed, catalysts have long been considered the Holy Grail of chemistry. In the conversion of methane gas to ethylene, the Holy Grail is a catalyst that can activate the first C–H bond of methane without oxidation. But it is very challenging, if not impossible for any catalyst as 4.35 eV is required to cleave the C-H bond while methyl radicals at 9.84 eV only form at the 12.6 eV ionization potential of methane.
Recently, Science  contrary to the requirement of 12.6 eV ionization potential reported the direct nonoxidative conversion of methane at the relatively high efficiency of 50% at 1363 K. The catalytic mechanism thought to explain the remarkable methane conversion efficiency without the formation of CO2 was based on passing the methane over a surface comprising single iron sites embedded in a silica matrix, the iron sites being 2-5 nm nanoparticles. Nanoconfinement of the iron sites in the silica surface was thought to initiate the catalytic generation of methyl radicals, followed by a series of gas-phase reactions.
Experimentally, the methyl radicals including the aforementioned methane reaction products were clearly observed with ultraviolet spectroscopy, Ibid. Theoretical support of the series of gas-phase reactions at 1225 K was simulated with DFT by assuming the nanoconfinement mechanism somehow formed a pair of methyl radicals at 9.84 eV. DFT stands for density functional theory. The DFT simulation showed the methyl radical pair to combine in a strongly exothermic process to produce ethylene, but otherwise leads to all of the methane reaction products.
The DFT simulation may explain how methyl radicals once formed combine to produce the methane reaction products, but does not explain how the nanoconfnement mechanism of iron sites in the silica surface produces the 9.84 eV necessary to form the methyl radicals. A catalytic mechanism capable of ionizing the methane molecule at 12.6 eV is required.
QED induced radiation is proposed as the catalytic mechanism capable of ionizing the methane molecule. QED stands for quantum electrodynamics. Finding basis in the QM requirement that the heat capacity of the atoms in the iron sites vanishes at the nanoscale, heat absorbed by the iron site from the silica matrix cannot be conserved by an increase in temperature. QM stands for quantum mechanics. Instead, conservation proceeds by the QED induced frequency up-conversion of the absorbed heat by the iron site to non-thermal EM radiation at its TIR confinement frequency. EM stands for electromagnetic and TIR for total internal reflection. QED induced catalysis by nanoparticles  is not new. Indeed, the EM radiation having Planck energy beyond the UV is sufficient to ionize methane molecules that come near the iron sites. See numerous QED applications at http://www.nanoqed.org
The QED induced catalytic conversion of methane by iron sites in a silica matrix may be significantly enhanced by flowing the methane through a cylindrical reactor provided with a removable liner comprising a nanoscale iron coating on a silica substrate, the substrate having a thickness of a few 10s of microns as shown the thumbnail. The liner may be formed by rolling-up a flat geometry where it is more convenient to control the nano coating thickness. A surface heater supplies the heat Q to the nanoscale iron coating, but by QM the nano coating cannot increase in temperature. Instead, QED induces the heat to be converted to EM radiation having Planck energy E = hc/λ, where h is Planck’s constant, c the velocity of light, and λ the wavelength of the QED radiation. The rate R of QED photons created is, R = Q/E.
Provided the refractive index RI of the coating is greater than that of the substrate, the wavelength λ of the QED radiation emitted is, λ = 2 n d , where n and d are the RI and thickness of the coating. For an iron (iron oxide) coating with a RI ≈ 3 on a silica substrate having RI ≈ 1.5, the QED condition on RI is satisfied, e.g., for iron oxide, λ ≈ 6 d and E ≈ hc/6d. The thumbnail shows E and λ vs. d for the ionization potential of methane (12.6 eV), the methyl radical (9.84 eV), and C-H bond cleavage (4.35 eV). E;g., the methane ionization potential E = 12.6 eV is reached for d = 17 nm thick iron coatings. .
1. The catalytic nature of nanoparticles by QED induced radiation is not new. The QM restriction of vanishing heat capacity of atoms in nanoparticles requires the conservation of any form of absorbed EM energy by the emission of QED radiation that enhances chemical reactions. .
2. QED induced radiation based on QM having the capability of ionizing natural gas explains the remarkable efficiency in catalytic surfaces comprising iron nanoparticles in a silica matrix is indeed the Holy Grail of catalysis..
3. By QED radiation, conversion efficiency may be significantly improved by flowing natural gas through a cylindrical reactor provided with a removable liner comprising a nanoscale iron coating on a silica substrate, although other more suitable materials may be used. The QED radiation wavelength depending on the thickness of the nano coating may be tailored to excite the desired quantum state of the flowing gas molecules simply by providing a set of liners with differing nano coating thicknesses. .
 X. Guo et al., “Direct, Nonoxidative Conversion of Methane to Ethylene, Aromatics, and Hydrogen.” Science 344, 616 (2014).
 T. Prevenslik, “Nanocatalysts by Quantum Electrodynamics Induced Electromagnetic Radiation,” Chin J Catal, 29(11), 1073 (2008).