A group of scientists at the Indian Institute of Science Education and Research (IISER), Kolkata, with the support from the government of India’s Department of Science & Technology (DST), under the Mission Innovation program, demonstrated a strategy to synthesize novel solid adsorbents, especially for carbon dioxide capture and utilization.

The group led by Professor Rahul Banerjee from IISER-Kolkata discovered special types of nanoparticles or microparticles which can capture CO₂ in their micro and mesoporous voids.

Carbon capture and utilization are growing research fields with their primary focus on reducing carbon dioxide emissions. With several industrial advancements already been demonstrated by various researchers, none of them have been economically viable and complete the carbon dioxide capture and utilization solution. The group claimed their research on solid absorbents might offer a vital material for carbon capture.

The novel materials with distinct physical properties on their surfaces that have been synthesized include porous Covalent Organic Frameworks (COF) like COF-graphene Janus thin films, porous covalent bonded organic nanotubes, and COF coated zeolite.

The 2D graphene sheets as a grafter helped the researchers to design and create COF-graphene Janus thin films through the interactions (non-covalent) between the COF and graphene, rendering flexible porous Janus films at the dichloromethane (DCM)-water interface.

The researchers claimed that the newly designed COF-coated zeolites could be an excellent candidate for carbon dioxide storage in the industry due to their high surface area and increased chemical stability.

The high carbon dioxide uptake for the COF coated zeolites, even after treatment with weak acids, makes it appropriate for industrial purposes. The COFs coating prevented the degradation of zeolite structure from moisture, weak acids, and water.

The research group recently discovered purely covalent bonded organic nanotubes (CONTs) with a structure unavailable until now through a novel bottom-up approach. The researchers claim that although zero-dimensional covalent organic cages and two- and three-dimensional covalent organic frameworks were previously reported, the synthesis of one-dimensional organic nanotubes was unheard of until now.

The synthesized CONTs have the edge over the analogous carbon nanotubes (CNTs) in functionalization, synthetic conditions, and porosity, exhibiting a higher Brunauer-Emmett-Teller (BET) surface area. Brunauer-Emmett-Teller (BET) surface area analysis is the multi-point measurement of an analyte’s specific surface area (m2/g) through gas adsorption analysis, where an inert gas such as nitrogen continuously flows over a solid sample, or the solid sample is suspended in a defined gaseous volume.

These CONTs are promising candidates for efficient carbon dioxide adsorption and have also showcased photosensitizing ability, which can convert the adsorbed carbon dioxide into carbon oxide upon irradiation of visible light.

Previously, the government of India’s Department of Science and Technology, to encourage translational research on carbon capture, utilization & storage (CCUS), had invited proposals from Indian researchers under the Accelerating CCUS Technologies (ACT) program in collaboration with other ACT member countries.

As suggested by Prime Minister Narendra Modi at the COP26 Summit in Glasgow last year, India intends to reduce 1 billion tons of carbon emissions until the end of the decade and reduce its economy’s carbon intensity by less than 45% by 2030.