On the mechanisms and the selectivity determining steps in syngas conversion over supported metal catalysts: An IR study

Isobutanol synthesis from syngas over K–Cu/ZrO 2 –La 2 O 3 ( x ) catalysts: Effect of La-loading

“…We have seen that amount of C1 intermediates, such as carbonate, formate species, enrich greatly over 3% LCZ catalyst. Bicarbonate and formate species have been proposed as the intermediates for methanol formation [48][49][50]. Higher alcohols can form directly from methanol, as shown using labeled methanol with syngas over an alkali-promoted Cu-based catalyst [51].…”

Development of an Innovative XRD-DRIFTS Prototype AllowingOperandoCharacterizations during Fischer-Tropsch Synthesis over Cobalt-Based Catalysts under Representative Conditions

“…Note that no methane, with its typical bands at 3 015 and 1 305 cm À1 [11,22], was detected inside the reaction cell, which is a good indication that the operando cell behaves as expected in a similar way as a fixed-bed reactor, without major products retrodiffusion. The bands at 2 370 and 2 330 cm À1 can be assigned to CO 2 , more likely from the outside atmosphere of the laboratory [9,11].…”

“…9). The band of very low intensity in the 1 900-2 000 cm À1 region could be assigned to bridged carbonyls [9,11,22]. This band is however visible only during the first hours of the reaction, before disappearing or being flooded in the major decrease of the silica bands between 1 990 and 1 630 cm À1 .…”

“…After few hours, the CO bands reached a maximum and stable level, indicating that the CO concentration in the cell was stabilized, at the expected CO partial pressure of 2 bar. The shoulder appearing at the early edge of the reaction at around 2 050 cm À1 can be assigned to linear carbonyls on metal cobalt or platinum [9,11,22]. Its intensity seems to decrease slightly with time on stream, but this apparent decrease could also be a simple mathematical effect due to the concomitant global decrease of the bands assigned to silica, especially those at 1 990, 1 865 and 1 630 cm À1 related to Si-O bond vibration (Fig.…”

“…The bands at 2 180 and 2 110 cm À1 are assigned to gaseous CO [11,22] flowing through the reaction cell. These bands appeared ten minutes after the switch between the N 2 flow and the syngas (H 2 +CO) flow, and increased until N 2 was completely removed from the cell.…”