Porous Carbon for CO2 Capture Technology: Unveiling Fundamentals and Innovations

Abstract

Porous carbon is an emerging material for the capture of CO2 from point sources of emissions due to its high structural, mechanical, and chemical stability, along with reusability advantages. Currently, research efforts are mainly focused on high- or medium-pressure adsorption, rather than low-pressure or DAC (direct air capture) conditions. Highly porous and functionalized carbon, containing heteroatoms (N, O, etc.), is synthesized using different activation synthesis routes, such as hard template, soft template, and chemical activation, to achieve high CO2 capture efficiency at various temperatures and pressure ranges. Fundamental pore formation mechanisms with different activation routes have been evaluated and explored. Higher porosity alone can be ineffective without the presence of proper saturated diffusion pathways for CO2 transfer. Therefore, it is imperative to emphasize more rational multi-hierarchical macro-/meso-/micro-/super-/ultra-pore design strategies to achieve a higher utilization efficiency of these pores. Moreover, the present research primarily focuses on powder-based hierarchical porous carbon materials, which may reduce the efficiency of the capture performance when shaping the powder into pellets or fixed-bed shapes for applications considered. Therefore, it is imperative to develop a synthesis strategy for pelletized porous carbon and to explore its mechanistic synthesis route and potential for CO2 capture.

Comprehensive Insights and Advancements in Gel Catalysts for Electrochemical Energy Conversion

“…Continuous emissions of CO 2 resulting from aggressively higher levels of energy consumption have negative environmental impacts on the Earth. To address the climate challenge and mitigate the concentration of atmospheric CO 2 (currently at 420 ppm), it is imperative to take action [67,68]. The electrochemical reduction of CO 2 to produce value-added products such as chemical feedstocks (carbonate, polycarbonate, and polymer building blocks, etc.)…”

Conductive Gels for Energy Storage, Conversion, and Generation: Materials Design Strategies, Properties, and Applications

“…These methods necessitate specialized, complex, and costly equipment. Moreover, the doping of carbon with heteroatoms requires the presence of a pre-assembled organic template that allows for composition tuning [102,103]. In this context, Saha et al have explored the use of a supramolecular Ni (II)-triazole gel as a novel synthetic precursor for creating a bifunctional electrocatalyst targeting both OER and HER (Figure 7) [104].…”

Potential of Carbon Aerogels in Energy: Design, Characteristics, and Applications

“…If pelletized precursors are used, factors such as the amount of organic precursors pelletized, pellet shape, size, thickness, pelletization compression range, and compression time are important ( Figure 5 ). The variability in these conditions leads to the production of carbon gels with distinct properties, highlighting the beauty of research in this field [ 41 ].…”

“…The activation process is conducted on the precursors of the organic or carbon gel, or their intermediary forms, employing various strategic approaches such as chemical activation, physical activation, hard template activation, soft template activation, gas template activation, and metal ion activation. This activation provides the three-dimensional porous structure with either perfect or enhanced surface area and porosity, facilitating ease of mass diffusion or internal access to catalytic active sites for applications related to energy storage and conversion [ 41 , 42 ].…”

“…To achieve the desired carbon pore structure in various energy materials for optimal performance, diverse synthesis strategies are employed to engineer the pore architecture. The introduction of effective hierarchical pore morphology, encompassing ultra-/super-/micro-/meso-/macropores, involves employing different activation methods such as chemical activation, physical activation, hard templating, and soft templating approaches [ 41 , 42 ]. Generally, the synthesis of sol–gel carbon products involves utilizing porogens, often considered as a form of soft templating, wherein the degradation of synthesis products yields gaseous templates (e.g., CO 2 , NH 3 , CO, H 2 , H 2 O, CH 4 ) at high-temperature carbonization, inducing porosity in the carbon structure.…”