Simultaneous Capture of N2O and CO2 from a N2O/N2/CO2/O2 Mixture with a Ni(II)-Pyrazolecarboxylate Framework

Nitrous oxide (N 2 O) is a potent greenhouse gas and a major contributor to ozone depletion. Its primary industrial emission source is tail gas from adipic acid production, which typically comprises a mixture of N 2 O, CO 2, N 2, and O 2 . Current technologies for the removal of N 2 O and CO 2 from tail gas are energy-intensive and operationally complex. Herein, for the first time, simultaneous capture of N 2 O and CO 2 from the quaternary mixture is achieved using a Ni(II)-pyrazolecarboxylate framework, BUT-167. This material demonstrated an exceptional adsorption capacity (135.8 cm 3 cm –3 at 40 kPa) and a high packing density (790 mg cm –3 ) for N 2 O, outperforming reported sorbents. Moreover, BUT-167 also exhibits a remarkable CO 2 adsorption capacity (101.5 cm 3 cm –3 at 4 kPa), achieving simultaneously high selectivity values of 257.6 for CO 2 /N 2 (4:96, v/v) and 135.7 for N 2 O/N 2 (40/60). Importantly, BUT-167 exhibits robust and outstanding dual-gas removal performance across multiple adsorption–desorption breakthrough cycles under both dry and humid conditions. The strong affinity toward CO 2 and N 2 O could be attributed to multiple hydrogen bonding interactions facilitated by its highly confined channel structure, as confirmed through single-crystal X-ray diffraction analysis.