MOF-Derived Robust and Synergetic Acid Sites Inducing C–N Bond Disruption for Energy-Efficient CO₂ Desorption

Abstract

Amine-based scrubbing technique is recognized as a promising method of capturing CO2 to alleviate climate change. However, the less stability and poor acidity of solid acid catalysts (SACs) limit their potential to further improve amine regeneration activity and reduce the energy penalty. To address these challenges, here, we introduce two-dimensional (2D) cobalt–nitrogen-doped carbon nanoflakes (Co–N–C NSs) driven by a layered metal–organic framework that work as SACs. The designed 2D Co–N–C SACs can exhibit promising stability, superhydrophilic surface, and acidity. Such 2D structure also contains well-confined Co–N4 Lewis acid sites and −OH Brønsted acid sites to have a synergetic effect on C–N bond disruption and significantly increase CO2 desorption rate by 281% and reduce the reaction temperatures to 88 °C, minimizing water evaporation by 20.3% and subsequent regeneration energy penalty by 71.7% compared to the noncatalysis.

Nonacid Carbon Materials as Catalysts for Monoethanolamine Energy-Efficient Regeneration

“…Therefore, it is possible for CNT to decompose HCO 3 – into CO 2 and OH – and then OH – is combined with MEAH + to release MEA. However, the N–C bond length change of MEACOO – was unfavorable, indicating that the N–C bond could not be activated by CNT as the way of solid acid catalysts. , It was noted that MEACOOH is more favorable to form through MEACOO – compared with zwitterion (eq ) during the regeneration . Hence, the effects of CNT on MEACOOH decomposition were investigated.…”

“…Catalyzing is an emerging energy-efficient strategy for amine regeneration at lower temperature (<100 °C). In this regard, solid acid catalysts including zeolites, solid super acids, metal oxides, and their derivatives have been applied to decrease heat duty in the regeneration process. − Generally, the acid sites and surface areas are considered to be determining factors for the catalytic performance of the solid acid. ,, Most of the reported solid acid catalysts with abundant acid sites can improve the regeneration rate of monoethanolamine (MEA) by over 30%. ,− However, a common issue that solid acid catalysts faced is the decreased performance during cyclic tests, making them inapplicable in large-scale industrialization. In view of chemical essence, the basicity of regeneration solution and high regeneration temperature can unavoidably make the degeneration of acid sites to some degree.…”

Embedded Mo/Mn Atomic Regulation for Durable Acidity-Reinforced HZSM-5 Catalyst toward Energy-Efficient Amine Regeneration

“…To further substantiate the superiority of 1/16MoMn 3/1 @H, we compared the CO 2 desorption performance achieved using 1/16MoMn 3/1 @H with that achieved using other catalysts in the literature at different temperatures and catalyst concentrations. ,− To determine this, we first correlated the effect of catalyst dosage on the capacity of CO 2 desorption (Figure S6e). The optimal reaction rate and diffusion rate reached equilibrium at a catalyst dosage of 1.25 wt %; thus, the catalytic performance of 1.25 wt % 1/16MoMn 3/1 @H was selected as a benchmark for comparison.…”

Energy-Saving Effect of Low-Cost and Environmentally Friendly Sepiolite as an Efficient Catalyst Carrier for CO2 Capture

“…Recently, the solid acid catalyst-aided CO 2 desorption process has attracted much attention aiming to minimize the energy consumption of the process: − the addition of solid acid catalysts allows the CO 2 desorption process to be performed at a relatively low temperature (below 100 °C), which not only accelerates the CO 2 desorption rate but also decreases the heat consumption for releasing CO 2 . It is commonly accepted that the main contributors for the high heat consumption during CO 2 desorption are the carbamate decomposition and deprotonation of protonated amine, and both processes involve proton transfer. , Solid acid catalysts can promote the two reaction processes mentioned above because of their remarkable acidity and the presence of the Brønsted and Lewis acid sites .…”