Mechanistic insights into the CO₂ capture and reduction on K-promoted Cu/Al₂O₃ by spatiotemporal operando methodologies

Abstract

Integrated CO2 capture and conversion processes bring the promise of drastic abatement of CO2 emission together with its valorisation to chemical building blocks such as CH4 and CO. Isothermal CO2...

The Need for Flexible Chemical Synthesis and How Dual-Function Materials Can Pave the Way

“…A crucial parameter for the effective performance of the DFMs is the proximity of the adsorption and catalytic sites, which has been discussed from their onset . DFMs typically operate through a spillover mechanism whereby the CO 2 for the catalytic reaction is supplied by a nearby adsorbent site, as the reactor is operated in a dynamic CO 2 reduction mode. ,, This spillover mechanism has already been observed in the literature. ,− , Figure shows the operando DRIFTS results of a nickel–ruthenium–potassium-based DFM in the CO 2 methanation and of a copper–potassium-based DFM in the RWGS. , In both cases, a fast reaction step occurs during the conversion step, followed by the spillover of the various carbonate species to the active metal sites for their subsequent conversion. Since the reaction pathway is unravelled by the in situ and operando characterization techniques, process intensification at the nanoscale can be achieved by developing materials with the most active species, further promoting a particular reaction route.…”

“…(2) Dynamic evolution of surface species of Cu–K/γ-Al 2 O 3 elucidated by operando DRIFTS during CCR at 350 °C in different positions of the catalyst bed from front (A) to back (D); (E) outlet gas composition at 350 °C. Reprinted with permission from refs and . Copyright 2023 MDPI/Copyright 2022 Royal Society of Chemistry…”

“…17,103,122 This spillover mechanism has already been observed in the literature. 103,[112][113][114]118 Figure 5 shows the operando DRIFTS results of a nickel−ruthenium−potassium-based DFM in the CO 2 methanation and of a copper−potassium-based DFM in the RWGS. 103,118 In both cases, a fast reaction step occurs during the conversion step, followed by the spillover of the various carbonate species to the active metal sites for their subsequent conversion.…”

“…103,[112][113][114]118 Figure 5 shows the operando DRIFTS results of a nickel−ruthenium−potassium-based DFM in the CO 2 methanation and of a copper−potassium-based DFM in the RWGS. 103,118 In both cases, a fast reaction step occurs during the conversion step, followed by the spillover of the various carbonate species to the active metal sites for their subsequent conversion. Since the reaction pathway is unravelled by the in situ and operando characterization techniques, process intensification at the nanoscale can be achieved by developing materials with the most active species, further promoting a particular reaction route.…”

“…An accurate prediction of the DFMs surface mechanism and active sites behavior in real chemistries via computational modeling is more complex than that in steady-state catalysis, but it is necessary to accelerate the scaling-up of the dynamic processes. , Forming structure–activity relationships through in situ and operando characterization will provide key information in this regard, allowing one to tailor DFMs to applications. Regarding the experimental investigation of the DFM surface mechanism, there are only few diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) studies that have been reported in the literature to date. ,− Hence, it is important to make connections between structure and activity, which belong to an underexplored part of the DFM research. For example, if the reaction mechanism for low-temperature RWGS in Figure is unravelled, research efforts can be focused on material design optimization.…”