RESUMO
It remains a significant challenge to construct an integrated catalyst that combines advantages of homogeneous and heterogeneous catalysis with clarified mechanism and high performance. Here we show atomically precise CuAg cluster catalysts for CO2 capture and utilization, where two functional units are combined into the clusters: metal and ligand. Due to atomic resolution on total and local structures of such catalysts to be achieved, which disentangles heterogeneous imprecise systems and permits tracing the reaction processes via experiments coupled with theory, site-specific catalysis induced by metal-ligand synergy can be accurately elucidated. The CuAg cluster catalysts exhibit excellent reactivity and recyclability to forge the C-N bonding from CO2 formylation with secondary amines that can make the cluster catalysts more unique compared with typically homogeneous complexes.
RESUMO
LaTi1-xMnxO3+δ (x = 0.2 and 0.4) perovskite-type catalysts are synthesized by acrylamide polymerization route and etched with diluted HNO3 for oxidation of toluene as one of typical volatile organic compounds (VOCs). The substitution of Mn cations improves catalytic activity (toluene conversion increased from 0 to 50.6% by substituting 40% of Ti cations with Mn cations) by improving abilities of light absorption and light-to-heat conversion, and acid etching further promotes catalytic activity (toluene conversion increased from 50.6%-95.6% for LaTi0.6Mn0.4O3+δ) by enlarging specific surface area, generating more surface active oxygen, strengthening mobility of surface oxygen, and improving low-temperature reducibility. To explore the origin of the light-driven photothermocatalytic activity of A-LaTi0.6Mn0.4O3+δ by EPR analysis, O2 desorption and H2 consumption, we find that the light is not only as a thermal source to provide energy for toluene oxidation but also can promote oxidation reaction by photoactivation.
RESUMO
Light-driven photothermocatalysis can provide enough energy to reach light-off temperature of VOCs on the surface of catalyst without auxiliary heat source. Herein, we synthesized noble-metal supported manganese oxide catalysts (xPt/MO) and studied their photothermal catalytic behavior of toluene degradation, where 1â¯Pt/MO (1â¯wt.% loading of Pt) and 2â¯Pt/MO (2â¯wt.% loading of Pt) exhibited more than 90 % of conversion and 70 % of mineralization under illumination of 200â¯mW/cm2 light intensity with a value of 30,000â¯mL/(g·h) for weight hourly space velocity (WHSV), respectively. Comparison to pure MO, 1â¯Pt/MO owns a good photothermal catalytic stability for at least 60â¯h without obvious deactivation. The introduction of Pt promotes the crystallization of MO (verified by XRD and TEM analysis) and enhances the mobility of surface/sub-surface lattice oxygen (verified by O2-TPD, H2-TPR and CO consumption). It is proved that illumination not only supplies thermal energy to trigger the reaction of toluene oxidation but also further evoke more lattice oxygen on Pt/MO to participate in toluene decomposition.
RESUMO
In this study, 396 samples from diarrheic pigs on 46 pig farms in Jiangsu Province, China, were analyzed by RT-PCR. One-hundred eighty-one pigs from 37 farms tested positive for porcine kobuvirus (PKV). Phylogenetic analysis of the 3D gene from 19 isolates showed sequence homology of 88.0 %-100 % and 69.4 %-100 % for nucleotides and amino acids, respectively, while similarity to isolates of other kobuviruses was 69.6 %-78.8 % and 27.8 %-56.9 %, respectively. One-hundred eighty-five samples contained two or more pathogens, and 31/68 PKV-positive samples tested positive for other diarrheic pathogens, confirming the existence of PKV infection and coinfection.
