Insight into catalytic performance and reaction mechanism for toluene total oxidation over Cu-Ce supported catalyst.

Herein, three supported catalysts, CuO/Al2O3, CeO2/Al2O3, and CuO-CeO2/Al2O3, were synthesized by the convenient impregnation method to reveal the effect of CeO2 addition on catalytic performance and reaction mechanism for toluene oxidation. Compared with CuO/Al2O3, the T50 and T90 (the temperatures at 50% and 90% toluene conversion, respectively) of CuO-CeO2/Al2O3 were reduced by 33 and 39 °C, respectively. N2 adsorption-desorption experiment, XRD, SEM, EDS mapping, Raman, EPR, H2-TPR, O2-TPD, XPS, NH3-TPD, Toluene-TPD, and in-situ DRIFTS were conducted to characterize these catalysts. The excellent catalytic performance of CuO-CeO2/Al2O3 could be attributed to its strong copper-cerium interaction and high oxygen vacancies concentration. Moreover, in-situ DRIFTS proved that CuO-CeO2/Al2O3 promoted the conversion of toluene to benzoate and accelerated the deep degradation path of toluene. This work provided valuable insights into the development of efficient and economical catalysts for volatile organic compounds.

Investigation of catalytic methane oxidation over Ag/Co2MOx (M = Co, Ni, Cu) catalysts with varying interfacial electron transfer.

Atom-doped Co3O4 catalysts loaded with Ag were examined as cost-effective catalysts for methane oxidation. The synthesized Ag/Co2NiOx catalysts exhibited distinctive surface characteristics in contrast with Ag/Co3O4 and Ag/Co2CuOx catalysts prepared using a similar method. Characterization results unveiled that Ag/Co2NiOx featured a higher presence of active surface oxygen species, lattice defects, a larger surface area, and enhanced reducibility. A methane oxidation catalytic performance followed the sequence: Ag/Co2NiOx > Ag/Co3O4 > Ag/Co2CuOx. The investigation delved into methane degradation pathways on the surfaces of three catalysts, examining their behavior under both aerobic and anaerobic atmospheres through in-situ DRIFTS analysis. Furthermore, introducing Ag showed a marked positive effect on Co-Ni mixed oxide, inducing electron transfer and a more active electron system, whereas it exhibited an inverse impact within the surface of Co-Cu mixed oxide. This work provides innovative perspectives on the development of forthcoming environmental catalysts.

Enhancement Effect Induced by the Second Metal to Promote Ozone Catalytic Oxidation of VOCs.

It is a promising research direction to develop catalysts with high stability and ozone utilization for low-temperature ozone catalytic oxidation of VOCs. While bimetallic catalysts exhibit excellent catalytic activity compared with conventional single noble metal catalysts, limited success has been achieved in the influence of the bimetallic effect on the stability and ozone utilization of metal catalysts. Herein, it is necessary to systematically study the enhancement effect in the ozone catalytic reaction induced by the second metal. With a simple continuous impregnation method, a platinum-cerium bimetallic catalyst is prepared. Also highlighted are studies from several aspects of the contribution of the second metal (Ce) to the stability and ozone utilization of the catalysts, including the "electronic effect" and "geometric effect". The synergistic removal rate of toluene and ozone is nearly 100% at 30 °C, and it still shows positive stability after high humidity and a long reaction time. More importantly, the instructive significance, which is the in-depth knowledge of enhanced catalytic mechanism of bimetallic catalysts resulting from a second metal, is provided by this work.

[Characteristics of Industrial Volatile Organic Compounds(VOCs) Emission in China from 2011 to 2019].

In order to better understand the industrial volatile organic compounds(VOCs) emissions in China in recent years, an industrial VOCs emission inventory was developed from 2011 to 2019, based on the dynamic emission factors method and the comprehensive source classification system. The results showed that VOCs emissions increased first from 11122.7 kt in 2011 to 13397.9 kt in 2017, and then decreased to 13247.0 kt in 2019. The emission structure of the four source categories changed. The contribution from basic organic chemical industries, gasoline storage and transportation, manufacturing(i.e., coatings, inks, pigments, and similar products), and industrial protective coatings continued to increase. On the contrary, the contributions of oil and natural gas processing, automobile, and container manufacturing industries declined over the study period. Among the industrial emissions in China in 2019, industrial coating, printing, and basic organic chemical industries emitted large amounts of VOCs(accounting for 39.2% of the total emission), and because their contribution became increasingly prominent since 2011, these sectors will be the key emission sources in the future. With respect to the spatial distribution in 2019, East China and South China had the largest VOCs emissions. Shandong, Guangdong, Jiangsu, and Zhejiang were the four provinces that contributed the most, accounting for 40.6% of the total VOCs emissions.