Hydrogen uptake of high surface area-activated carbons doped with nitrogen

• Published in: International journal of hydrogen energy 2013-08, Vol.38 (25), p.10453-10460
• Main Authors: Zhao, W., Fierro, V., Fernández-Huerta, N., Izquierdo, M.T., Celzard, A.
• Format: Article
• Language: English
• Subjects: Acoustics; Activated carbon; Alternative fuels. Production and utilization; Analysis of variance; Applied sciences; Carbon; Chemical Sciences; Condensed Matter; Doping; Electromagnetism; Energy; Engineering Sciences; Exact sciences and technology; Fuels; Hydrogen; Hydrogen storage; Material chemistry; Materials; Materials Science; Mechanics; Mechanics of materials; Nitrogen doping; Physics; Polymers; Surface area; Surface chemistry; Thermics; Uptakes; Ureas
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2013.06.048

Three activated carbons (ACs) having apparent surface areas higher than 2500 m2/g were doped with nitrogen by treatment with urea at 623 K under air flow. Nitrogen contents as high as 15.1 wt.% were obtained, but resulting in decreased surface areas and pore volumes. Hydrogen storage capacities of ACs before and after nitrogen doping were measured at 77 K and up to 8 MPa. After doping, the hydrogen uptake was lower due to the corresponding decrease of surface area. Statistical, ANOVA, analysis of the relevancy of surface area and nitrogen content on hydrogen storage at 77 K was carried out, taking into account our data and those data available in the open literature. We concluded that surface area controls hydrogen adsorption and nitrogen content is not a relevant parameter. Comparison of our results with data from the open literature reporting excess hydrogen uptake versus SBET for activated carbons having N content between 0.1 and 20 wt.%: SBET controls hydrogen adsorption, which is independent on N content. [Display omitted] •Activated carbons with nitrogen contents as high as 15.1 wt.% were prepared.•Porous texture is the main parameter controlling hydrogen adsorption at 77 K.•Nitrogen content has not significant effect on hydrogen adsorption at 77 K.•Our conclusions were validated by many experimental data from the literature.