Pregled bibliografske jedinice broj: 1087001
Isomerization of Cyclohexane over Bifunctional Pt-, Au-, and PtAu-Heteropoly Acid Catalysts
Isomerization of Cyclohexane over Bifunctional Pt-, Au-, and PtAu-Heteropoly Acid Catalysts // ACS Catalysis, 9 (2019), 6; 5063-5073 doi:10.1021/acscatal.9b00592 (međunarodna recenzija, članak, znanstveni)
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Naslov
Isomerization of Cyclohexane over Bifunctional Pt-, Au-, and PtAu-Heteropoly Acid Catalysts
Autori
Alazman, Abdulrahman ; Belic, Domagoj ; Alotaibi, Abdullah ; Kozhevnikova, Elena F. ; Kozhevnikov, Ivan V.
Izvornik
ACS Catalysis (2155-5435) 9
(2019), 6;
5063-5073
Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni
Ključne riječi
isomerization ; cyclohexane ; bifunctional catalysis ; platinum ; gold ; heteropoly acid
Sažetak
Isomerization of cyclohexane was investigated in the presence of monofunctional acid and bifunctional metal–acid catalysts based on Keggin-type heteropoly acid H3PW12O40 and Pt and Au as the metal components using a differential fixed-bed microreactor at 180–300 °C, ambient pressure and a C6H12/H2 partial pressure ratio of 0.04–0.14. Particular emphasis was placed on the acidic Cs salt, Cs2.5H0.5PW12O40 (CsPW) as the acid catalyst and Pt/CsPW, Au/CsPW, and PtAu/CsPW as the bifunctional catalysts. Pt/CsPW and Au/CsPW were more efficient than the monofunctional acid catalyst CsPW, and Pt/CsPW was more active than Au/CsPW with both giving >99% selectivity to methylcyclopentane. It was found with Pt/CsPW that the cyclohexane dehydrogenation step equilibrated at a molar ratio of Pt and H+ surface sites Pt/H+ ≥ 0.7, which is much higher than for Pt/zeolite. PtAu/CsPW bimetallic catalyst exhibited a 2-fold higher activity in cyclohexane isomerization and a 3.5-fold higher activity in the accompanying dehydrogenation of cyclohexane to benzene than the mixture of Pt/CsPW and Au/CsPW with the same metal loading. The enhancing effect of gold is assigned to PtAu bimetallic particles, which had a higher Pt dispersion than the Pt in Pt/CsPW. Scanning transmission electron microscopy–energy dispersive X-ray spectroscopy (STEM-EDX) revealed bimetallic PtAu particles in PtAu/CsPW with a wide range of Pt/Au atomic ratios. No enhancing effect of gold was found in the case of carbon-supported catalyst PtAu/C physically mixed with CsPW, and the STEM-EDX analysis revealed no modification of Pt sites by Au in this catalyst.
Izvorni jezik
Engleski
Znanstvena područja
Fizika, Kemija, Interdisciplinarne prirodne znanosti, Kemijsko inženjerstvo
Citiraj ovu publikaciju:
Časopis indeksira:
- Current Contents Connect (CCC)
- Web of Science Core Collection (WoSCC)
- Science Citation Index Expanded (SCI-EXP)
- SCI-EXP, SSCI i/ili A&HCI
- Scopus
