Dextrose-aided hydrothermal preparation with large surface area on 1D single-crystalline perovskite La0.5Sr0.5CoO3 nanowires without template: Highly catalytic activity for methane combustion

Abstract

Single-crystalline nanowires of perovskite-type oxides (PTOs) La0.5Sr0.5CoO3 were synthesized via a dextrose-assisted hydrothermal route (DHR) and/or l-Lysine. The physicochemical properties of the materials were characterized by means of XRD, BET, HRSEM, HRTEM, SAED, ICP-AES, H2-TPR, and O2-TPD techniques. It is found that the single-crystalline sample (LSCO-2) derived at temperature of 170°C with a dextrose/l-Lysine volumetric ratio of 0.3/1.0 of new nanowire DHR possessed a high surface oxygen concentration and the best low-temperature reducibility, and a high surface area (17.7m2g−1) from nitrogen sorption analysis which exhibited much better than that observed with the corresponding perovskites synthesized by conventional process for polycrystalline La0.5Sr0.5CoO3 catalyst. The average width and length of the nanowires are 5–10nm and 2μm, respectively. Among the LSCO samples, the LSCO-2 sample showed the best performance for methane combustion, giving the T10%, T50%, and T90% of 249, 461 and 702°C at GHSV=30,000ml/(hgcat), respectively. After running at 800°C for 50h, the nanowire DHR (LSCO-2) showed a higher stability and activity than the nanoparticles (LSCO-4) counterpart. It indicated that the good catalytic performance of LSCO-2 was related to higher surface area/energies, and better low-temperature reducibility, as well as to the different adsorbed oxygen species concentration.