Cu-based N-doped/undoped graphene nanocomposites as electrocatalysts for the oxygen reduction
- 98 Downloads
The development of efficient electrocatalysts for the energy-related reactions, based on earth-abundant elements, is extremely important for a sustainable energetic future. Herein, we report the application of Cu nanoparticles supported on undoped and N-doped graphene—Cu/GOE and Cu/GOE-u composites, respectively—as electrocatalysts for the oxygen reduction reaction (ORR). All the materials showed ORR electrocatalytic activities in alkaline medium. The Cu/GOE-u composite exhibited the most promising performance, with an onset potential of 0.84 V and a current density of jL = − 4.4 mA cm−2 (vs. 0.84 V and − 2.8 mA cm−2 for Cu/GOE), which revealed the great influence of the created Cu–Nx/C active sites on the ORR electrocatalytic activity. The pure GOE-u support showed worse performance than the GOE, demonstrating that the N-doping advantage is not linear and also depends on the type and amount of accessible active sites created. The N-doping allowed an increase in the selectivity for the 4-electron process, resulting in a % of H2O2 produced < 25% for Cu/GOE-u (vs. almost 75% for Cu/GOE). Both nanocomposites revealed good tolerance to methanol crossover, and the Cu/GOE-u displayed a moderate long-term electrochemical stability, with current retention of 84% after 20,000 s.
KeywordsCu-based nanocomposites Graphene N-doping Cu–Nx/C active sites Oxygen reduction reaction
This work was co-financed by Fundação para a Ciência e a Tecnologia (FCT)/MEC and EU under FEDER founds (Grant No. POCI/01/0145/FEDER/007265) and Programme PT2020 (Project UID/QUI/50006/2013), Project Charphite—ERAMIN/0006/2015—and by Project UNIRCELL—POCI-01-0145-FEDER-016422—funded by European Structural and Investment Funds (FEEI) through—Programa Operacional Competitividade e Internacionalização—COMPETE2020.
- 9.Nunes M, Rocha IM, Fernandes DM, Mestre AS, Moura CN, Carvalho AP, Pereira MFR, Freire C (2015) Sucrose-derived activated carbons: electron transfer properties and application as oxygen reduction electrocatalysts. RSC Adv 5(124):102919–102931. https://doi.org/10.1039/C5RA20874B CrossRefGoogle Scholar
- 13.Mun Y, Kim MJ, Park S-A, Lee E, Ye Y, Lee S, Kim Y-T, Kim S, Kim O-H, Cho Y-H, Sung Y-E, Lee J (2018) Soft-template synthesis of mesoporous non-precious metal catalyst with Fe-Nx/C active sites for oxygen reduction reaction in fuel cells. Appl Catal B Environ 222:191–199. https://doi.org/10.1016/j.apcatb.2017.10.015 CrossRefGoogle Scholar
- 16.Osmieri L, Escudero-Cid R, Armandi M, Ocón P, Monteverde Videla AHA, Specchia S (2018) Effects of using two transition metals in the synthesis of non-noble electrocatalysts for oxygen reduction reaction in direct methanol fuel cell. Electrochim Acta 266:220–232. https://doi.org/10.1016/j.electacta.2018.02.036 CrossRefGoogle Scholar
- 18.Wu H, Li H, Zhao X, Liu Q, Wang J, Xiao J, Xie S, Si R, Yang F, Miao S, Guo X, Wang G, Bao X (2016) Highly doped and exposed Cu(I)–N active sites within graphene towards efficient oxygen reduction for zinc–air batteries. Energy Environ Sci 9:3739–3745. https://doi.org/10.1039/c6ee01867j Google Scholar
- 20.Lu L, Fan J, Lei W, Ouyang Y, Yao D, Xia X, Hao Q (2018) Multiple metal (Cu, Mn, Fe) centered species simultaneously combined nitrogen-doped graphene as a new electrocatalyst for oxygen reduction in alkaline and neutral solutions. ChemCatChem 10(11):2471–2480. https://doi.org/10.1002/cctc.201800152 CrossRefGoogle Scholar
- 21.Morales MV, Rocha M, Freire C, Asedegbega-Nieto E, Gallegos-Suarez E, Rodriguez-Ramos I, Guerrero-Ruiz A (2017) Development of highly efficient Cu versus Pd catalysts supported on graphitic carbon materials for the reduction of 4-nitrophenol to 4-aminophenol at room temperature. Carbon 111:150–161. https://doi.org/10.1016/j.carbon.2016.09.079 CrossRefGoogle Scholar
- 22.Dongil AB, Bachiller-Baeza B, Guerrero-Ruiz A, Rodriguez-Ramos I (2011) Chemoselective hydrogenation of cinnamaldehyde: a comparison of the immobilization of Ru-phosphine complex on graphite oxide and on graphitic surfaces. J Catal 282(2):299–309. https://doi.org/10.1016/j.jcat.2011.07.002 CrossRefGoogle Scholar
- 25.Bard AJF, Faulkner LR (2001) Electrochemical methods, fundamentals and applications. Wiley, New YorkGoogle Scholar