Effects of thermal aging on the electronic and structural properties of Pt-Pd and toluene oxidation activity

Engineering of lattice defects in supported Cu-Mn-Ce composite oxide catalysts through ultra-low Pd doping and plasma treatment for catalytic oxidation of hexane

Despite the low cost of supported non-precious metal catalysts, their catalytic activity is significantly lower than that of precious metal catalysts in the catalytic oxidation reaction of volatile organic compounds (VOCs). In order to enhance the catalytic activity of supported non-precious metal catalysts, we introduced an ultra-low loading of palladium into the existing catalytic system and employed a plasma preparation process instead of the conventional impregnation method. The approach significantly improves the catalytic activity of the active sites on the catalyst. The results indicate that, compared to the supported Pd and CuMnCeOx catalysts prepared by conventional impregnation method, the Pd/CuMnCeOx/SiO2-P catalysts prepared via plasma exhibit a higher proportion of lattice defects (oxygen vacancies). Furthermore, the doping of the ultra-low Pd could facilitate the formation of additional lattice defects in the composite oxide. As a result, it can improve the content of surface active oxygen and enhance the adsorptive strength of hexane on the surface of the catalyst. The Pd/CuMnCeOx/SiO2-P catalysts exhibit high catalytic activity and stability in the catalytic oxidation of n-hexane. This work promotes the potential application in the preparation of catalyst with ultra-low precious metal loading.

Recent Advances of the Effect of H2O on VOC Oxidation over Catalysts: Influencing Factors, Inhibition/Promotion Mechanisms, and Water Resistance Strategies

Water vapor is a significant component in real volatile organic compounds (VOCs) exhaust gas and has a considerable impact on the catalytic performance of catalysts for VOC oxidation. Important progress has been made in the reaction mechanisms of H2O and water resistance strategies for VOC oxidation in recent years. Despite advancements in catalytic technology, most catalysts still exhibit low activity under humid conditions, presenting a challenge in reducing the adverse effects of H2O on VOC oxidation. To develop water-resistant catalysts, understanding the mechanistic role of H2O and implementing effective water-resistance strategies with influencing factors are imperative. This Perspective systematically summarizes related research on the impact of H2O on VOC oxidation, drawing from over 390 papers published between 2013 and 2024. Five main influencing factors are proposed to clarify their effects on the role of H2O. Five inhibition/promotion mechanisms of H2O are introduced, elucidating their role in the catalytic oxidation of various VOCs. Additionally, different kinds of water resistance strategies are discussed, including the fabrication of hydrophobic materials, the design of specific structures and morphologies, and the introduction of additional elements for catalyst modification. Finally, scientific challenges and opportunities for enhancing the design of efficient and water-resistant catalysts for practical applications in VOC purification are highlighted.

Catalytic Oxidation of Benzene over Atomic Active Site AgNi/BCN Catalysts at Room Temperature

Benzene is the typical volatile organic compound (VOC) of indoor and outdoor air pollution, which harms human health and the environment. Due to the stability of their aromatic structure, the catalytic oxidation of benzene rings in an environment without an external energy input is difficult. In this study, the efficient degradation of benzene at room temperature was achieved by constructing Ag and Ni bimetallic active site catalysts (AgNi/BCN) supported on boron-carbon-nitrogen aerogel. The atomic-scale Ag and Ni are uniformly dispersed on the catalyst surface and form Ag/Ni-C/N bonds with C and N, which were conducive to the catalytic oxidation of benzene at room temperature. Further catalytic reaction mechanisms indicate that benzene reacted with ·OH to produce R·, which reacted with O2 to regenerate ·OH. Under the strong oxidation of ·OH, benzene was oxidized to form alcohols, carboxylic acids, and eventually CO2 and H2O. This study not only significantly reduces the energy consumption of VOC catalytic oxidation, but also improves the safety of VOC treatment, providing new ideas for the low energy consumption and green development of VOC treatment.