PNNL

Abstract

Transformation of captured CO2 into value-added chemicals to mitigate increasing CO2 concentration in the atmosphere has gained significant attention recently. Though the carbon capture and storage (CCS) is already been practiced in few places, it suffers from energy-intensive CO2 desorption and compression steps involved, which can be avoided in the carbon capture and utilization (CCU) approach. Herein, a selection of carbon capture solvents were screened to assess the reactivity of condensed-phase heterogeneous metal catalyzed hydrogenation of CO2. Among catalysts screened, Cu/ZnO/Al2O3 catalyst was active for the one-pot CO2 capture and conversion to methanol process using post and pre-combustion carbon capture solvents comprised of various amines and alcohols. Our findings indicate that formamides are less-reactive under our conditions, in comparison to formate ester intermediates noting that a combination of 1° alcohols and amines gives the highest methanol yield. Screening volatile organic compound (VOC)-free alcohols and amines led us to an environmentally benign system of bio-derived and biodegradable chitosan and polyethylene glycol (PEG200), which provide moderate concentration of methanol (139.5 mmol/L) with a facile separation of volatile products (water and methanol). The chitosan/PEG200 system was recycled three times, ultimately providing a promising VOC-free, biodegradable, bio-derived and recyclable CO2 capture and conversion pathway.