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Otrzymywanie syntetycznych cząstek MoS2 za pomocą metody mokrej

Wojtalik Michał, Przybyt Przybysław, Zubańska Katarzyna, Żuchowska Monika, Bojarska Zuzanna, Arasimowicz-Andres Monika, Rożeń Antonii, Makowski Łukasz

Przemysł Chemiczny

2019

T. 98, nr 11

1817--1821

Przedstawiono pełną procedurę otrzymywania syntetycznych nanocząstek disiarczku molibdenu za pomocą metody mokrej. W tym celu zastosowano roztwory heptamolibdenianu amonu, siarczku amonu oraz kwasu cytrynowego jako katalizatora reakcji. Proces prowadzono w sposób ciągły, stosując reaktory zderzeniowe. Podano metodę separacji MoS₂ z mieszaniny poreakcyjnej oraz jego krystalizacji. Przeprowadzono również badania nad potencjalnymi zastosowaniami uzyskanego produktu.

(NH₄)₆Mo7O₂₄, (NH₄)₂S and citric acid solns. were introduced into the impinging jet reactor with coaxial and tangential type inlets to obtain MoS₂ nanoparticles. The resulting ppt. was washed with water, dried at 50oC for 24 h and calcined in a furnace under Ar for 1 h. The particle size distribution was detd. by using a laser diffraction particle size analyzer. Sepd. particles smaller than 300 nm were dispersed in engine oil and their effect on rheol. and tribol. properties was examd.

Graphene oxide-based nano-materials as catalysts for oxygen reduction reaction

Bojarska Zuzanna, Mazurkiewicz-Pawlicka Marta, Makowski Łukasz

Chemical and Process Engineering

2019

Vol. 40, nr 4

361–-376

The aim of the presented research was to test different carbon supports, such as graphene oxide (GO), graphene oxide modified with ammonia (N-GO), and reduced graphene oxide (rGO) for catalysts used in a low-temperature fuel cell, specifically a proton exchange membrane fuel cell (PEMFC). Modification of the carbon supports should lead to different catalytic activity in the fuel cell. Reduction of GO leads to partial removal of oxygen groups from GO, forming rGO. Modification of GO with ammonia results in an enrichment of GO structure with nitrogen. A thorough analysis of the used supports was carried out, using various analytical techniques, such as FTIR spectroscopy and thermogravimetric (TGA) analysis. Palladium and platinum catalysts deposited on these supports were produced and used for the oxygen reduction reaction (ORR). Catalytic activity tests of the prepared catalysts were carried out in a home-made direct formic acid fuel cell (DFAFC). The tests showed that the enrichment of the GO structure with nitrogen caused an increase in the catalytic activity, especially for the palladium catalyst. However, reduction of GO resulted in catalysts with higher activity and the highest catalytic activity was demonstrated by Pt/rGO, because platinum is the most catalytically active metal for ORR. The obtained results may be significant for low-temperature fuel cell technology, because they show that a simple modification of a carbon support may lead to a significant increase of the catalyst activity. This could be useful especially in lowering the cost of fuel cells, which is an important factor, because thousands of fuel cells running on hydrogen are already in use in commercial vehicles, forklifts, and backup power units worldwide. Another method used for lowering the price of current fuel cells can involve developing new clean and cheap production methods of the fuel, i.e. hydrogen. One of them employs catalytic processes, where carbon materials can be also used as a support and it is necessary to know how they can influence catalytic activity.