Novel Nanocomposite Materials for Oxygen Separation Membranes
The Russia-Japan conference “Advanced Materials: Synthesis, Processing and Properties of Nanostructures – 2016”
30 Oct - 3 Nov 2016
conference_type.international conference, Novosibirsk
|| Sadykov Vladislav Aleksandrovich
, Fedorova Yuliya E.
, Lukashevich Anton Igorevich
, Vostrikov Zakhar Yurʹevich
, Eremeev Nikita Fedorovich
, Krasnov Aleksey
, Skriabin Pavel Ivanovich
Boreskov Institute of Catalysis SB RAS
Novosibirsk State University
Novosibirsk State Pedagogical University
Developing catalytic membranes reactors for producing syngas from biofuels by selective oxidation by oxygen separated from air is important problem of hydrogen energy field. The key parts of this problem are design of materials for such membranes functional layers and optimization of techniques of their deposition. General requirements for these materials are chemical and thermomechanical stability under high gradient of the oxygen chemical potential, high oxygen mobility and surface reactivity, high selectivity in the partial oxidation of fuels into syngas and relative cheapness. Nanocomposite materials based upon praseodymium nickelate-cobaltite PrNi0.5Co0.5O3-δ – Ce0.9Y0.1O2-δ (PNC – YDC) are promising here due to high oxygen mobility provided by the fast oxygen diffusion channel (DO up to ~ 10^(-7) cm2/s at 700 °C), which appeared due to cation redistribution between PNC and YDC nanodomains and developed interface [1,2].
Individual oxides PrNi0.5Co0.5O3-δ and Ce0.9Y0.1O2-δ were synthesized by modified Pechini route with PNC – YDC nanocomposite being obtained via ultrasonic dispersion of these powders in isopropanol in weight ratio 1:1. A few PNC – YDC functional layers (mesoporous, microporous and dense), dense MnFe2O4 – Ce0.9Gd0.1O2-δ buffer layer and porous Pt/Sm0.15Pr0.15Ce0.35Zr0.3O2 δ catalytic layer were consecutively deposed on Ni/Al foam substrate. Each layer was sintered at 1100 °C (900 °C for catalytic layer). The membranes obtained were tested in CH4 selective oxidation into syngas/oxidry reforming.
According to results of testing, the temperature distribution on the membrane surface is sufficiently uniform. The selectivity of methane oxidation into syngas rises with the inlet methane concentration due to decreasing the coverage of the catalytic particles surface by reactive oxygen species. The oxygen permeability of membrane (the oxygen flux is up to 10 ml O2/cm2min at 950 °C under air/methane gradient) meets criteria of the practical application . Syngas yield and methane conversion increase with temperature and contact time. The outlet H2 and CO concentrations ratio varies depending on contact time and the inlet carbon dioxide concentration. H2/CO concentration ratio is < 1 for contact times < 0.14 s at 950 °C (feed 46 % CO2 + 48 % natural gas + N2), CH4 conversion is up to 60 %. Stable performance of the membrane was demonstrated for at least 200 h time-on-stream.
Hence, the materials applied in this work are promising as the functional components of membranes for the oxygen separation from air and methane oxidation into syngas by this oxygen.