Materials and Processes for Carbon Dioxide Capture and Utilisation

Materials and processes for CO2 capture and utilisation are an essential part of a holistic approach toward a sustainable energy future. CO2 and energy are tightly intertwined as energy produced from fossil fuel combustion always generates CO2. A major environmental concern, CO2 could also become an invaluable resource for making carbon-based materials and chemicals, and a means to store energy in CO2-derived fuels. In this Special Issue of C, the reader can appreciate the complexity of the challenge from the perspective of energy production process engineering; materials science and chemistry; waste management; cross-disciplinary approach to policy and public engagement. Electrical power generation from fossil fuels combustion is a major emitter of CO2. Low carbon high quality power generation can be achieved using IGCC (Integrated Gasification Combined Cycle) technologies, where coal, for example, is converted to a gas mixture rich in H2 and CO2, with the latter captured before H2 combustion. In such an IGCC power plant, hot H2 combustion gasses drive a gas turbine, while heat from the coal gasifier is used to generate steam to drive a steam turbine, each coupled to a dedicated electric generator. Key to low carbon emissions is the pre-combustion capture process. In this Special Issue, Peampermpool et al. [1] at Curtin University show how 92% of CO2 can be separated by means of a two-stage capture process consisting of (i) CO2 cryogenic liquefaction, followed by (ii) expansion of resulting CO2-lean gases through an orifice. Aspen HYSYS simulations of an energy-saving scheme specifically designed for this process indicate that the energy burden for CO2 capture for a 740 MW IGCC GE power plant could be limited to 7.4–7.8%. It follows that process engineering can improve CO2 capture technologies, as such carbon capture materials must also be improved as addressed in the next paragraph. Novel materials for CO2 capture are essential to decarbonise fossil-based energy production while transitioning to renewable-based energy generation. Very large amounts of CO2 must be captured to be then used or stored. Efficient carbon capture materials are thus instrumental to CO2 utilisation and storage. Porous carbon materials achieve high CO2 capture capacities, while selectivity may be enhanced in the presence of chemical functional groups. Carbon foams with a large variety of functional groups can be prepared from H2SO4-dehydrated para-nitroaniline, as reported in the contribution of Andreoli and Barron [2]. Almost 35 atom % of surface nitrogen on these foams is amine and/or aromatic N, both known to enhance selective CO2 adsorption. This is also confirmed by the value of heat of adsorption, 113.6 kJ/mol, in the range typical of amine-based chemical sorbents. In a related contribution, Ghosh and Barron [3] studied the role of Lewis base (LB) moieties including amines on CO2 chemical sorption. The computational study shows how LB moieties alone cannot explain enhanced CO2 capture via poly-CO2 formation. For poly-CO2 to be stable, Lewis acid (LA) moieties such as H+, AlF3, B4O6 should also be present to form LB-C(O)O-[C(O)O]n-C(O)O-LA species, where LA is bound to the negatively charged terminal oxygen. Direct air capture (DAC) is the formidable challenge of capturing CO2 directly from the Earth’s atmosphere. The Glaser group at the University of Missouri-Columbia has specialised in the study and development of rubisco-inspired biomimetic approaches to the reversible capture of CO2 from