Development of Flowerlike Ce_1-XZr_xO_2-δ-Dispersed Paper-Structured Catalyst for Direct-Biogas SOFC

Abstract

Ce0.5Zr0.5O2-δ (CZ) with a high specific surface area and high oxygen storage capacity (OSC) was synthesized by a two-step hydrothermal process to obtain a flowerlike geometry, which can prevent the sintering of Ni under a reducing atmosphere. Durability tests on the prepared paper-structured catalysts (PSCs) for dry reforming of methane (DRM) at 750°C revealed that for both cases with and without CZ dispersion (Ni/CZ-PSC and Ni-PSC, respectively), the methane conversions were stable with degradation rates of 3.70% and 15.2% kh−1, respectively. After the one-week DRM test, the weights of the deposited carbon were 0.2 and 3.4 times those of the PSCs for Ni/CZ-PSC and Ni-PSC, respectively. Ni sintering and its detachment from the ceramic fiber that occurred in the Ni-PSC was solved by the dispersion of CZ (Ni/CZ-PSC) due to its unique morphology and high OSC.

Paper‐structured catalyst with a dispersion of ceria‐based oxide support for improving the performance of an SOFC fed with simulated biogas

“…The coking rate during the 100 h galvanostatic test was only 0.43 mg‐C g‐PSC −1 h −1 for the Ni/CZ(F)‐PSC, whereas it was 8.1 mg‐C g‐PSC −1 h −1 for the Ni‐PSC (Table 2). These values are substantially lower than those of cells without an ESC (1.3 and 21 mg‐C g‐PSC −1 h −1 for the Ni/CZ(F)‐PSC and Ni‐PSC, respectively) [40]. These results indicate the promotion of an internal reforming reaction with the oxygen transported from the cathode side to the anode side during power generation, which can electrochemically remove the carbon formed on the Ni surface (C + 2O 2− → CO 2 + 2e − ).…”

“…The CZ(F) was prepared by a two-step hydrothermal process [39,40]. In the first step, 2.17 g of cerium(III) nitrate hexahydrate (Ce(NO 3 ) 3 ⋅6H 2 O; Chameleon Reagent), 1.8 g of glucose (Sigma-Aldrich), and 1.44 g of acrylic acid (Sigma-Aldrich) were dissolved in 80 mL of deionized (DI) water under magnetic stirring.…”

“…For the Ni-PSC (Figure 3a), Ni particles were loaded onto the Cf surface (Figure 3b). Ni particles easily agglomerated and coarsened on the smooth surface, resulting in lower catalytic activity, which led to coking [39,40]. Therefore, dispersion of the catalyst support particles is indispensable.…”

“…A Ce 0.5 Zr 0.5 O 2 solid solution with a flowerlike geometry (CZ(F)) and a higher oxygen storage capacity (OSC; 536 µmol O 2 g −1 ) compared with that of CeO 2 (284 µmol O 2 g −1 ) was developed as a catalyst support to promote the DRM [39,40]. The resultant CZ(F) is composed of microspheres in which oxide petals form a mesoporous structure to block the agglomeration of metal particles loaded onto the microspheres [39][40][41].…”

“…A Ce 0.5 Zr 0.5 O 2 solid solution with a flowerlike geometry (CZ(F)) and a higher oxygen storage capacity (OSC; 536 µmol O 2 g −1 ) compared with that of CeO 2 (284 µmol O 2 g −1 ) was developed as a catalyst support to promote the DRM [39,40]. The resultant CZ(F) is composed of microspheres in which oxide petals form a mesoporous structure to block the agglomeration of metal particles loaded onto the microspheres [39][40][41]. The OSC (i.e., the ability to release and store lattice oxygen under reducing and oxidizing atmospheres, respectively) can contribute to the oxidative removal of carbonaceous species deposited onto the catalyst surface [42,43].…”