Asap 2010

Textural characterization of the samples was carried out by means of physical adsorption of N₂ at −196 °C in a Micromeritics ASAP 2010 and adsorption of CO₂ at 0 °C in a Micromeritics TriStar 3000. Helium density was measured in an Accupyc 1330 at 35 °C. The samples were outgassed at 100 °C under vacuum overnight prior to adsorption measurements.
The use of both adsorbates, N₂ and CO₂, provides complementary information about the porous texture of the samples: the adsorption of CO₂ at 0 °C and up to 1 bar is restricted to pores narrower than 1 nm, whereas N₂ adsorption at −196 °C covers wider pore sizes but presents diffusion limitations in the narrower pores. The total pore volume (V_p) was calculated from the amount of N₂ adsorbed at a relative pressure of 0.99, and the BET surface area from the Brunauer-Emmett-Teller equation [29 (link)]. The micropore volume (W₀) and the micropore surface area (S_DR) were determined from the Dubinin-Radushkevich (DR) [30 (link)] and Dubinin-Astakhov (DA) [31 (link)] equations assuming a density of the adsorbed phase of 0.808 cm³·g⁻¹ for N₂ and 1.023 cm³·g⁻¹ for CO₂, a cross sectional area of 0.162 nm² for N₂ and 0.187 nm² for CO₂ and finally an affinity coefficient of 0.34 for N₂ and 0.36 for CO₂. The average micropore width (L₀) was calculated through the Stoeckli-Ballerini equation [32 (link)].

Elemental analyses (EA) were performed on Elementar Vario EL Cube elemental analyzer to determine the sulfur content in ACFC. Nitrogen adsorption−desorption isotherms and pore size distribution of ACFC were characterized by accelerated surface area and porosimetry system (Micromeritics, ASAP 2010). The morphology and dispersion of sulfur of composite cathodes were observed with scanning electron microscopes (SEM, JEOL, JSM-6380LA and SEM, JEOL, JSM-6330F) equipped with energy dispersive X-ray spectrometer (EDS).

Plasma-Atomic Emission Spectrometry (ICP-AES) was inductively used to test the Cu and Ni contents in the prepared catalysts using a FR-T-RR-01, CURI. The phase and crystallinity of the catalysts and YC were identified by X-ray diffraction (XRD) using X'Pert Pro PANalytical diffractometer equipped with a detector operating Cu Kα radiation (λ = 1.540598 Å; 40 kV and 30 mA). The X-ray fluorescence (XRF) was used to explore the chemical composition of raw YC. The catalysts' morphology was illustrated by a scanning electron microscopy (SEM) using QUANTA 200 FEI instrument at 30 kV. BET surface area was carried out by N2-adsorption at 77 K using a Micromeritics ASAP 2010 instrument.