Single and Dual Metal Oxides as Promising Supports for Carbon Monoxide Removal from an Actual Syngas: The Crucial Role of Support on the Selectivity of the Au–Cu System

Abstract

A catalytic screening was performed to determine the effect of the support on the performance of an Au–Cu based system for the removal of CO from an actual syngas. First, a syngas was obtained from reforming of ethanol. Then, the reformer outlet was connected to a second reactor, where Au–Cu catalysts supported on several single and dual metal oxides (i.e., CeO2, SiO2, ZrO2, Al2O3, La2O3, Fe2O3, CeO2-SiO2, CeO2-ZrO2, and CeO2-Al2O3) were evaluated. AuCu/CeO2 was the most active catalyst due to an elevated oxygen mobility over the surface, promoting CO2 formation from adsorption of C–O* and OH− intermediates on Au0 and CuO species. However, its lower capacity to release the surface oxygen contributes to the generation of stable carbon deposits, which lead to its rapid deactivation. On the other hand, AuCu/CeO2-SiO2 was more stable due to its high surface area and lower formation of formate and carbonate intermediates, mitigating carbon deposits. Therefore, use of dual supports could be a promising strategy to overcome the low stability of AuCu/CeO2. The results of this research are a contribution to integrated production and purification of H2 in a compact system.

Catalytic Temperature Effects on Conversion Efficiency of PM2.5 and Gaseous Emissions from Rice Husk Combustion

“…This results in a poor flue particle (PM) combustion phase. At temperatures below 260 • C, the activity of the catalyst is reduced [41], indicating low performance. However, as the temperature of the detachable catalyst increases, it creates a large temperature difference between the two catalysts in a reverse order and CO adsorption increases.…”

Monoliths washcoated with AuCu catalysts for CO removal in an ethanol fuel processor: Effect of CeO2–SiO2 dual support on the catalytic performance and reactor cost

“…However, the high demand of CeO 2 for environmental applications and industrial processes [33] has increased its price. Figure 2a shows that the average cost of CeO 2 doubles other supports used in CO removal, such as ZrO 2 , Al 2 O 3 , FeO 2 and SiO 2 [27]. Likewise, considering the overall price of the catalyst (i.e., active metals plus support) , the AuCu/CeO 2 has a cost 73 % higher when compared to the other options (Figure 2b).…”

“…Secondly, we identified an Au-Cu catalyst (with an Au/Cu molar ratio = 1 [25]) supported on nanoparticles of CeO 2 [26] as promising to perform CO removal from an actual syngas in a single unit. We chose CeO 2 as support among other alternatives (i.e., CeO [27]) due to its greater activity to oxidize CO; CeO 2 morphology was also studied, finding that a polyhedra nano-shape is an active and stable support for CO removal over a AuCu/CeO 2 system [26]. Now, our intention is to structure the AuCu/CeO 2 catalyst to favor the development of a compact B-FPU [3].…”

“…Figure 2a shows that SiO 2 is the cheapest support. Besides, in a preliminary study [27] it was identified that although the inclusion of a second metal oxide (i.e., ZrO 2 , Al 2 O 3 and SiO 2 ) in the CeO 2 matrix decreases its activity in CO removal, this effect is less significant in the CeO 2 -SiO 2 system. The evaluation was carried out by fixing a Ce/Si molar ratio of 1 in the catalysts.…”

Pt/Re/CeO2 Based Catalysts for CO-Water–Gas Shift Reaction: from Powders to Structured Catalyst

“…The water-gas shift (WGS) reaction [1] is an exothermic reaction, whose process is generally performed through two adiabatic stages, at high (HTS) [2] and low temperatures (LTS) [3]. WGS can be considered as the first syngas purification step to obtain high purity hydrogen, and in fact, it allows for the reduction of the CO percentage and increase of the hydrogen yield in the reformate gas stream [4]. The two-stages process configuration allows us to achieve higher conversions at relatively smaller volumes.…”