Co 3 O 4 catalysts supported on paper-like stainless steel fibers (PSSF) were prepared by MOFs-templated (M) method and applied for catalytic combustion of isopropanol. Physicochemical properties of the as-synthesized Co 3 O 4 catalysts were investigated by SEM, EDS mapping, TEM, XRD , BET, XPS and H 2 -TPR, respectively. Characterization results of SEM and TEM shown that Co 3 O 4 (M)-350 and Co 3 O 4 (M)-400 still remained the dodecahedron shape of the ZIF-67 precursor and possessed porous structures. The XPS results shown that the ratio of Co 3+ /Co 2+ and O c /O c + O a + O l firstly increased and then decreased with the increase of calcination temperature. Among the as-synthesized catalysts, Co 3 O 4 (M)-400 exhibited the highest activity for the catalytic combustion of isopropanol with the T 50 and T 90 values of 258 °C and 281 °C, respectively, which was associated with high BET surface area, high amount of Co 3+ species and abundant surface chemisorbed oxygen. Moreover, Co 3 O 4 (M)-400 was employed as a structured catalyst for isopropanol combustion, the catalytic kinetics were studied based on different feed concentration, bed height and GHSV. The experimental results indicated that the T 50 and T 90 of isopropanol combustion over Co 3 O 4 (M)-400 with the bed height of 2 cm were increased slightly as the GHSV and feed concentration of isopropanol increased.
Wei Zhanxiang,Qin Cong,Yang Xuhui,Zhu Linghao,Zhao Xiaoyan,Cao Jianliang,Wang Yan
Abstract The detection of hazardous CO gas is an important research content in the domain of the Internet of Things (IoT). Herein, we introduced a facile metal-organic frameworks (MOFs)-templated strategy to synthesize Cd-doped Co 3 O 4 nanosheets (Cd-Co 3 O 4 NSs) aimed at boosting the CO-sensing performance. The synthesized Cd-Co 3 O 4 NSs feature a multihole nanomeshes structure and a large specific surface area (106.579 m 2 ·g -1 ), which endows the sensing materials with favorable gas diffusion and interaction ability. Furthermore, compared with unadulterated Co 3 O 4 , the 2 mol % Cd-doped Co 3 O 4 (2% Cd-Co 3 O 4 ) sensor exhibits enhanced sensitivity (244%) to 100 ppm CO at 200 °C and a comparatively low experimental limit of detection (0.5 ppm/experimental value). The 2% Cd-Co 3 O 4 NSs show good selectivity, reproducibility, and long-term stability. The improved CO sensitivity signal is probably owing to the stable nanomeshes construction, high surface area, and rich oxygen vacancies caused by cadmium doping. This study presents a facile avenue to promote the sensing performance of p-type metal oxide semiconductors by enhancing the surface activity of Co 3 O 4 combined with morphology control and component regulation. Graphical Abstract
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