scholarly journals Increasing the Size-Selectivity in Laser-Based g/h Liquid Flow Synthesis of Pt and PtPd Nanoparticles for CO and NO Oxidation in Industrial Automotive Exhaust Gas Treatment Benchmarking

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1582 ◽  
Author(s):  
S. Dittrich ◽  
S. Kohsakowski ◽  
B. Wittek ◽  
C. Hengst ◽  
B. Gökce ◽  
...  

PtPd catalysts are state-of-the-art for automotive diesel exhaust gas treatment. Although wet-chemical preparation of PtPd nanoparticles below 3 nm and kg-scale synthesis of supported PtPd/Al2O3 are already established, the partial segregation of the bimetallic nanoparticles remains an issue that adversely affects catalytic performance. As a promising alternative, laser-based catalyst preparation allows the continuous synthesis of surfactant-free, solid-solution alloy nanoparticles at the g/h-scale. However, the required productivity of the catalytically relevant size fraction <10 nm has yet to be met. In this work, by optimization of ablation and fragmentation conditions, the continuous flow synthesis of nanoparticles with a productivity of the catalytically relevant size fraction <10 nm of >1 g/h is presented via an in-process size tuning strategy. After the laser-based preparation of hectoliters of colloid and more than 2 kg of PtPd/Al2O3 wash coat, the laser-generated catalysts were benchmarked against an industry-relevant reference catalyst. The conversion of CO by laser-generated catalysts was found to be equivalent to the reference, while improved activity during NO oxidation was achieved. Finally, the present study validates that laser-generated catalysts meet the size and productivity requirements for industrial standard operating procedures. Hence, laser-based catalyst synthesis appears to be a promising alternative to chemical-based preparation of alloy nanoparticles for developing industrial catalysts, such as those needed in the treatment of exhaust gases.

Author(s):  
Daiya Kobayashi ◽  
Hirokazu Kobayashi ◽  
Kohei Kusada ◽  
Tomokazu Yamamoto ◽  
Takaaki Toriyama ◽  
...  

We report PtW solid-solution alloy nanoparticles (NPs) as a reverse water-gas shift (RWGS) reaction catalyst for the first time. Atomic-level alloying of Pt and W significantly enhanced the RWGS reaction activity of Pt NPs.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1260
Author(s):  
Stefanie Duvigneau ◽  
Robert Dürr ◽  
Jessica Behrens ◽  
Achim Kienle

Biopolymers are a promising alternative to petroleum-based plastic raw materials. They are bio-based, non-toxic and degradable under environmental conditions. In addition to the homopolymer poly(3-hydroxybutyrate) (PHB), there are a number of co-polymers that have a broad range of applications and are easier to process in comparison to PHB. The most prominent representative from this group of bio-copolymers is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). In this article, we show a new kinetic model that describes the PHBV production from fructose and propionic acid in Cupriavidus necator (C. necator). The developed model is used to analyze the effects of process parameter variations such as the CO2 amount in the exhaust gas and the feed rate. The presented model is a valuable tool to improve the microbial PHBV production process. Due to the coupling of CO2 online measurements in the exhaust gas to the biomass production, the model has the potential to predict the composition and the current yield of PHBV in the ongoing process.


2004 ◽  
Vol 54 (3) ◽  
pp. 193-200 ◽  
Author(s):  
Henrik Birgersson ◽  
Lars Eriksson ◽  
Magali Boutonnet ◽  
Sven G. Järås
Keyword(s):  

2010 ◽  
Vol 21 (41) ◽  
pp. 415603 ◽  
Author(s):  
S Gómez-de Pedro ◽  
M Puyol ◽  
J Alonso-Chamarro

1993 ◽  
Author(s):  
Herbert R. Zweig ◽  
Stanley Fischler ◽  
William R. Wagner

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