Chemisorption of CO2 on Nitrogen-Doped Graphitic Carbons

Riku Shibuya; Kotaro Takeyasu; Donghui Guo; Takahiro Kondo; Junji Nakamura

doi:10.1021/acs.langmuir.2c01987

Chemisorption of CO₂ on Nitrogen-Doped Graphitic Carbons

Langmuir. 2022 Nov 29;38(47):14430-14438. doi: 10.1021/acs.langmuir.2c01987. Epub 2022 Nov 15.

Authors

Riku Shibuya¹, Kotaro Takeyasu^{2

3

4}, Donghui Guo², Takahiro Kondo^{2

3

4

5}, Junji Nakamura^{2

3

6}

Affiliations

¹ Graduate school of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki305-8573, Japan.
² Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki305-8573, Japan.
³ Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki305-8573, Japan.
⁴ R&D Center for Zero CO2 Emission Functional Materials, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki305-8573, Japan.
⁵ The Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi980-8577, Japan.
⁶ Mitsui Chemicals, Inc., Carbon Neutral Energy Research Center (MCI-CNRC), International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoka819-0395, Japan.

PMID: 36377773
DOI: 10.1021/acs.langmuir.2c01987

Abstract

The adsorption of CO₂ on nitrogen-doped graphitic carbon materials, such as graphene nanosheet (GNS) powder and highly oriented pyrolytic graphite (HOPG), was comparatively studied using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). Desorption of CO₂ was observed at approximately 380 K for both pyridinic-nitrogen (pyri-N)-doped GNS and pyri-N-doped HOPG samples in the TPD experiments, whereas no CO₂ desorption was observed for graphitic nitrogen-doped HOPG. This indicated that only pyri-N species create identical CO₂ adsorption sites on any graphitic carbon surface. The adsorption energies of CO₂ on pyri-N-doped carbons were estimated between 101 and 108 kJ mol^-1, indicating that chemisorption, rather than physisorption, took place. The CO₂ adsorption/desorption process was reproducible in repeated measurements, and no CO₂ dissociation occurred during the process, suggesting that it is a promising CO₂ capturing material. The O 1s peak of the adsorbed CO₂ clearly appeared at 531.5-532 eV in the XPS measurements. The N 1s peak of pyri-N did not change with CO₂ adsorption, indicating that CO₂ is not directly bound to pyri-N but is adsorbed on a carbon atom near the pyridinic nitrogen via the nonbonding p_z orbital of the carbon atom.