Shibuya Riku, Takeyasu Kotaro, Guo Donghui, Kondo Takahiro, Nakamura Junji
Graduate school of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki305-8573, Japan.
Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki305-8573, Japan.
Langmuir. 2022 Nov 29;38(47):14430-14438. doi: 10.1021/acs.langmuir.2c01987. Epub 2022 Nov 15.
The adsorption of CO 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 CO 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 CO desorption was observed for graphitic nitrogen-doped HOPG. This indicated that only pyri-N species create identical CO adsorption sites on any graphitic carbon surface. The adsorption energies of CO on pyri-N-doped carbons were estimated between 101 and 108 kJ mol, indicating that chemisorption, rather than physisorption, took place. The CO adsorption/desorption process was reproducible in repeated measurements, and no CO dissociation occurred during the process, suggesting that it is a promising CO capturing material. The O 1s peak of the adsorbed CO clearly appeared at 531.5-532 eV in the XPS measurements. The N 1s peak of pyri-N did not change with CO adsorption, indicating that CO is not directly bound to pyri-N but is adsorbed on a carbon atom near the pyridinic nitrogen via the nonbonding p orbital of the carbon atom.
采用程序升温脱附（TPD）和X射线光电子能谱（XPS）对CO在氮掺杂石墨碳材料（如石墨烯纳米片（GNS）粉末和高度取向热解石墨（HOPG））上的吸附进行了比较研究。在TPD实验中，吡啶氮（pyri-N）掺杂的GNS和pyri-N掺杂的HOPG样品在约380 K时均观察到CO脱附，而石墨氮掺杂的HOPG未观察到CO脱附。这表明只有pyri-N物种在任何石墨碳表面上产生相同的CO吸附位点。CO在pyri-N掺杂碳上的吸附能估计在101至108 kJ/mol之间，表明发生的是化学吸附而非物理吸附。CO吸附/脱附过程在重复测量中具有可重复性，且在此过程中未发生CO解离，这表明它是一种很有前景的CO捕获材料。在XPS测量中，吸附的CO的O 1s峰明显出现在531.5 - 532 eV处。pyri-N的N 1s峰在CO吸附时没有变化，表明CO不是直接与pyri-N结合，而是通过碳原子的非键p轨道吸附在吡啶氮附近的碳原子上。
