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The hydrogen and carbon monoxide separation is an important step in the hydrogen production process. If H2 can be selectively removed from the product side during hydrogen production in membrane reactors, then it would be possible to achieve complete CO conversion in a single‐step under high temperature conditions. In the present work, the multilayer amorphous‐Si‐B‐C‐N/γ‐Al2O3/α‐Al2O3 membranes with gradient porosity have been realized and assessed with respect to the thermal stability, geometry of pore space and H2/CO permeance. The α‐Al2O3 support has a bimodal pore‐size distribution of about 0.64 and 0.045 µm being macroporous and the intermediate γ‐Al2O3 layer—deposited from boehmite colloidal dispersion—has an average pore‐size of 8 nm being mesoporous. The results obtained by the N2‐adsorption method indicate a decrease in the volume of micropores—0.35 vs. 0.75 cm3 g−1—and a smaller pore size −6.8 vs. 7.4 Å—in membranes with the intermediate mesoporous γ‐Al2O3 layer if compared to those without. The three times Si‐B‐C‐N coated multilayer membranes show higher H2/CO permselectivities of about 10.5 and the H2 permeance of about 1.05 × 10−8 mol m−2 s−1 Pa−1. If compared to the state of the art of microporous membranes, the multilayer Si‐B‐C‐N/γ‐Al2O3/α‐Al2O3 membranes are appeared to be interesting candidates for hydrogen separation because of their tunable nature and high‐temperature and high‐pressure stability.

Low-layered, transparent graphene is accessible by a chemical vapor deposition (CVD) technique on a Ni-catalyst layer, which is deposited on a <100> silicon substrate. The number of graphene layers on the substrate is controlled by the grain boundaries in the Ni-catalyst layer and can be studied by micro Raman analysis. Electrical studies showed a sheet resistance (R(sheet)) of approximately 1435 Ω per □, a contact resistance (R(c)) of about 127 Ω, and a specific contact resistance (R(sc)) of approximately 2.8×10(-4)  Ω cm(2) for the CVD graphene samples. Transistor output characteristics for the graphene sample demonstrated linear current/voltage behavior. A current versus voltage (I(ds)-V(ds)) plot clearly indicates a p-conducting characteristic of the synthesized graphene. Gas-sensor measurements revealed a high sensor activity of the low-layer graphene material towards H(2) and CO. At 300 °C, a sensor response of approximately 29 towards low H(2) concentrations (1 vol %) was observed, which is by a factor of four higher than recently reported.

Polymer-derived amorphous silicon oxycarbide (SiOC) ceramics are designed for hydrogen separation at high temperatures. To form amorphous SiOC top-coating with the thickness of about 300 nm, tubular porous g-Al 2 O 3 /a-Al 2 O 3 substrates with gradient porosity are threefold coated by vinylfunctionalized polysiloxane and pyrolyzed at 700 C under argon. N 2 -physisorption measurement confirms formation of microporous material with a specific surface area of about 400 m 2 g -1 . Single gas permeance characterization of the SiOC membrane at 300 C reveals H 2 /CO 2 and H 2 /SF 6 ideal permselectivities of about 10 and 320, respectively. The experimental gas permeance data are modeled using solid-state diffusion (for He and H 2 ) and gas translational diffusion (for CO 2 and SF 6 ) mechanisms.