Manganese-promoted Rh supported on a modified SBA-15 molecular sieve for ethanol synthesis from syngas. Effect of manganese loading

Abstract

A modified mesoporous molecular sieve SBA-15 possessing larger pore diameter, pore volume, and high hydrothermal stability was developed. Loaded with RhCl 3 and Mn(NO 3 ) 2 , the as-prepared SBA-15 performed excellently in catalyzing direct conversion of syngas to ethanol. The highest perimeter of Rh-MnO interface and ethanol yield were reached at the Mn/Rh weight ratio of about 1. High CO conversion, more than 90% in the first three hours, was obtained over the catalyst 7 wt% Rh-7 wt% Mn/SBA-15. Improved catalytic performance is attributed to the increase in the amount of reducible oxide, which resulted in an enhancement of the perimeter of the Rh-MnO interface when the Mn/Rh weight ratio is about 1, and the enhanced ability of rhodium to dissociate and to hydrogenate the carbon monoxide molecule by the addition of manganese.

Formation, dynamics, and long-term stability of Mn- and Fe-promoted Rh/SiO2 catalysts in CO hydrogenation

“…13 Whereas others proposed that MnO x stabilizes Rh + sites at their interface and ultimately promotes CO insertion. [14][15][16][17][18] On the contrary, Yu and co-workers proposed that Rh + sites are not stable under reaction conditions and thereby not relevant for the StE reaction. 19 Similarly, the role of Fe as promoter for Rh-based catalysts is still under debate and controversially discussed.…”

Automated Generation and Analysis of the Complex Catalytic Reaction Network of Ethanol Synthesis from Syngas on Rh(111)

“…In order to simulate the experimental conditions, − we chose three temperatures ( T = 523, 573, and 623 K) and three pressures (log­( p /bar) = 0.5, 1, and 1.5) and set the H 2 :CO ratio as 2:1.…”

DRIFTS study of Fe promoter effect on Rh/Al2O3 catalyst for C2 oxygenates synthesis from syngas

“…9, it can be observed from Fig. 10 that the rate of CO (l) decreases more slowly on the 2Rh-4Fe/Al 2 O 3 , revealing that the addition of Fe stabilized CO(l) species under H 2 Temperature-programmed surface reduction (TPSR) is one of the most effective methods to study hydrogenation activity of chemically adsorbed CO [26,27]. Methane is easily desorbed and its formation includes the steps as CO dissociation and hydrogenation, so its formation temperature and peak intensity is usually used as a tool to measure the CO dissociation ability and hydrogenation capacity of catalyst [7].…”