The catalytic activities of the supported PdO catalysts were found to be dependenton the kind of the support as follows: CeO2>ZrO2>TiO2>Al2O3>SnO2>ZSM-5>SiO2.The reduction state of PdO in the catalys...The catalytic activities of the supported PdO catalysts were found to be dependenton the kind of the support as follows: CeO2>ZrO2>TiO2>Al2O3>SnO2>ZSM-5>SiO2.The reduction state of PdO in the catalyst played an important role in the oxidation activityof the catalyst. PdO/CeO2 was inferior to PdO/Al2O3 in heat-stability, but its activity for COoxidation was higher than PdO/Al2O3, after it had been calcinated at 1200 ℃ for 4 h.展开更多
The extraction of metallic nanoparticles from perovskite-type oxides(ABO_(3)) under mild reducing conditions is a novel way to prepare well-dispersed supported catalysts(B/AOd). Herein, we found that the encapsulated ...The extraction of metallic nanoparticles from perovskite-type oxides(ABO_(3)) under mild reducing conditions is a novel way to prepare well-dispersed supported catalysts(B/AOd). Herein, we found that the encapsulated PdO in perovskite LaCoO_3(PdO@LaCoO_3) could facilitate the phase transformation of the perovskite structure at a low temperature owing to both strong H2 spillover of Pd and intimate interaction between the encapsulated PdO and LaCoO_(3). The pure LaCoO_(3) without PdO was relatively inert to CO_(2) hydrogenation(CO_(2) conversion <4%). In contrast, PdO@LaCoO_(3) exhibited excellent CO_(2) methanation performance with 62.3% CO_(2) conversion and >99% CH4 selectivity. The characterization results demonstrated that the catalytically active Co2 C was in-situ formed by carburization of the extracted Co0 during CO_(2) methanation for the PdO@LaCoO_(3) sample. Whereas, the LaCoO_(3) with surface supported PdO(PdO/LaCoO_(3)) showed a weak interaction and remained a perovskite structure with few Co_(2)C active centers after the catalytic reaction, which was similar to the parent LaCoO_(3). Accordingly, the PdO/LaCoO_(3) showed an inferior catalytic performance with 31.8% CO_(2) conversion and 87.4% CH_(4) selectivity. Therefore, the designed encapsulation structure of PdO within perovskite is critical to extract metallic NPs from perovskite-type oxides, which has the potential to prepare other integrated nanocatalysts based on perovskite-type oxides.展开更多
文摘The catalytic activities of the supported PdO catalysts were found to be dependenton the kind of the support as follows: CeO2>ZrO2>TiO2>Al2O3>SnO2>ZSM-5>SiO2.The reduction state of PdO in the catalyst played an important role in the oxidation activityof the catalyst. PdO/CeO2 was inferior to PdO/Al2O3 in heat-stability, but its activity for COoxidation was higher than PdO/Al2O3, after it had been calcinated at 1200 ℃ for 4 h.
基金supported by the National Natural Science Foundation of China (Nos. 21536010 and 41673088)。
文摘The extraction of metallic nanoparticles from perovskite-type oxides(ABO_(3)) under mild reducing conditions is a novel way to prepare well-dispersed supported catalysts(B/AOd). Herein, we found that the encapsulated PdO in perovskite LaCoO_3(PdO@LaCoO_3) could facilitate the phase transformation of the perovskite structure at a low temperature owing to both strong H2 spillover of Pd and intimate interaction between the encapsulated PdO and LaCoO_(3). The pure LaCoO_(3) without PdO was relatively inert to CO_(2) hydrogenation(CO_(2) conversion <4%). In contrast, PdO@LaCoO_(3) exhibited excellent CO_(2) methanation performance with 62.3% CO_(2) conversion and >99% CH4 selectivity. The characterization results demonstrated that the catalytically active Co2 C was in-situ formed by carburization of the extracted Co0 during CO_(2) methanation for the PdO@LaCoO_(3) sample. Whereas, the LaCoO_(3) with surface supported PdO(PdO/LaCoO_(3)) showed a weak interaction and remained a perovskite structure with few Co_(2)C active centers after the catalytic reaction, which was similar to the parent LaCoO_(3). Accordingly, the PdO/LaCoO_(3) showed an inferior catalytic performance with 31.8% CO_(2) conversion and 87.4% CH_(4) selectivity. Therefore, the designed encapsulation structure of PdO within perovskite is critical to extract metallic NPs from perovskite-type oxides, which has the potential to prepare other integrated nanocatalysts based on perovskite-type oxides.
