TiO₂ Coating Strategy for Robust Catalysis of the Metal–Organic Framework toward Energy-Efficient CO₂ Capture

Abstract

High energy duty restricts the application of amine-based absorption in CO2 capture and limits the achievement of carbon neutrality. Although regenerating the amine solvent with solid acid catalysts can increase energy efficiency, inactivation of the catalyst must be addressed. Here, we report a robust metal–organic framework (MOF)-derived hybrid solid acid catalyst (SO4 2–/ZIF-67-C@TiO2) with improved acidity for promoting amine regeneration. The TiO2 coating effectively prevented the active components stripping from the surface of the catalyst, thus prolonging its lifespan. The well-protected Co–N x sites and protonated groups introduced onto the TiO2 surface increased the amount and rate of CO2 desorption by more than 64.5 and 153%, respectively. Consequently, the energy consumption decreased by approximately 36%. The catalyzed N–C bond rupture and proton transfer mechanisms are proposed. This work provides an effective protection strategy for robust acid catalysts, thus advancing the CO2 capture with less energy duty.

Perspective on Sorption Enhanced Bifunctional Catalysts to Produce Hydrocarbons

“…In this perspective, we address the solid metal oxide sorbents for CO 2 capture by chemical adsorption that have been combined with heterogeneous catalysts for SECs. Albeit, there are other solid sorbents, including physical adsorption using activated carbon and carbon nanomaterials, graphite/graphene, zeolites adsorbents, MOFs, and chemical adsorption using amine-supported silica adsorbents. − The materials discussed below can be used for DAC, pre-, and postcombustion CO 2 capture. In practice, however, several sorbents would be thermodynamically favored at one specific application based on the temperature ranges, pressures, CO 2 concentration in the feed gas, and impurities such as water vapor, O 2 , SOx, and NOx (Table ).…”

“…In this perspective, we address the solid metal oxide sorbents for CO 2 capture by chemical adsorption that have been combined with heterogeneous catalysts for SECs. Albeit, there are other solid sorbents, including physical adsorption using activated carbon and carbon nanomaterials, 70 graphite/graphene, 71 zeolites adsorbents, 72 MOFs, 73 and chemical adsorption using amine-supported silica adsorbents. 74−76 The materials discussed below can be used for DAC, pre-, and postcombustion CO 2 capture.…”

Reducing Heat Duty of MEA Regeneration Using a Sulfonic Acid-Functionalized Mesoporous MCM-41 Catalyst

“…To avoid environmental hazards and solve the separation problems, heterogeneous catalytic processes for CO 2 desorption using solid acid catalysts have been widely investigated in MEA-based post-combustion CO 2 capture . Different types of solid acid catalysts have been added to CO 2 -rich amine to enhance the desorption rate, such as metal–organic frameworks, carbonic anhydrase, transition-metal oxides, , sulfated metal oxides, and hydroxy metal oxides . Among these solid acid catalysts, the zeolite molecular sieves focus on abundant research because of their high surface area, hydrothermal stability, and controllable acid strength. , However, the zeolite molecular sieves possess low intrinsic acidity, limiting their catalytic efficiency in MEA regeneration, because the catalytic CO 2 desorption is influenced by the quantities of acid sites in catalysts …”

Water-Dispersible Nanocatalysts with Engineered Structures: The New Generation of Nanomaterials for Energy-Efficient CO2 Capture

“…Throughout the past decade, a broad span of heterogeneous solid acid catalysts ranging from metal-oxides (e.g., ZnO and MoO 3 ) to nanoporous materials (e.g., modified montmorillonite and HZSM-5 zeolite) and nanocomposites (e.g., Fe promoted SO 4 2– /ZrO 2 /MCM-41 and SO 4 2– /ZIF-67-C@TiO 2 ) have been tested in catalyst-aided solvent regeneration processes. Despite intensive research and development efforts, industrial-scale uptake of catalytic solvent regeneration technology has not been widely adopted due to the drawbacks of heterogeneous catalysis, such as operating challenges and low efficiency in the liquid phase.…”

“…22 This lower operating temperature not only avoids the loss of the latent heat of vaporization, it also paves the way for hot water streams from green and renewable energy resources (e.g., solar hot water) or those already available in the processes (e.g., hot process water streams) to be used for solvent regeneration, thereby significantly reducing operating costs. Throughout the past decade, a broad span of heterogeneous solid acid catalysts ranging from metal-oxides (e.g., ZnO 23 and MoO 3 24 ) to nanoporous materials (e.g., modified montmorillonite 25 and HZSM-5 zeolite 26 ) and nanocomposites (e.g., Fe promoted SO 4 2− /ZrO 2 /MCM-41 27 and SO 4 2− /ZIF-67-C@ TiO 2 28 ) have been tested in catalyst-aided solvent regeneration processes. Despite intensive research and development efforts, industrial-scale uptake of catalytic solvent regeneration technology has not been widely adopted due to the drawbacks of heterogeneous catalysis, such as operating challenges and low efficiency in the liquid phase.…”