Cobalt-based perovskite catalysts showed excellent performance towards NO–NO₂ oxidation. We systematically investigated the influence of different levels of Cu-doping on the catalytic performance of hexagonal phase LaCoO₃ (LaCo_1−xCu_xO₃ (x = 0.1, 0.2, 0.3)) for NO oxidation. The catalytic activities of the oxide catalysts followed the sequence: LaCo_0.9Cu_0.1O₃ > LaCoO₃ > LaCo_0.8Cu_0.2O₃ > LaCo_0.7Cu_0.3O₃ where the highest NO conversion for LaCo_0.9Cu_0.1O₃ was 82% at 310 °C. The relevant structural characterizations were conducted by XRD, BET, FTIR and TEM. The interaction between Co and Cu promoted the conversion of NO to NO₂. Upon increasing the Cu doping content, a decrease of the performance resulted from the generation of isolated CuO on the surface of the oxides, confirmed using H₂-TPR and XPS. Combined with first-principle calculations, we explored the reaction mechanism of NO oxidation on the surface and found that Cu doping would facilitate the reaction by decreasing the energy of oxygen vacancy formation and the NO₂ desorption barrier from Co- or Cu-nitrite.

This work reports the development of a Ni@yolk-ZrO₂ catalyst, which could be a potential solution to tackling challenges in hydrogen production.

A series of La_1−xBa_xCoO₃ (x = 0, 0.1, 0.2, 0.3) perovskites were synthesized by the modified sol–gel method, and their activities for NO oxidation were investigated as well. The relevant structural characterizations of the prepared catalysts were conducted by XRD, ICP, BET, FTIR, TEM, H₂-TPR and NO-TPD. The performance evaluation indicated that introduction of Ba at the A-site in LaCoO₃ greatly improved the activity for NO oxidation. The best performance with NO conversion of 93% at 265 °C was obtained on La_0.9Ba_0.1CoO₃. Additionally, the Ba-doped LaCoO₃ had better performance than that of the classical Pt/Al₂O₃ catalyst, implying that the non-noble catalysts could be considered as potential substituting candidates for noble metal-based catalysts.

Nano-gold (sub-5 nm)@mesoporous-silica (m-SiO₂) core–shell nanospheres with controlled size and core number were prepared via a soft-templated method. The single-core Au@m-SiO₂ particles showed great sintering-resistance at 750 °C and kept high catalytic activity for CO oxidation after the treatment.