title: Sulfur-doped carbons prepared from eutectic mixtures containing hydroxymethylthiophene as metal-free oxygen reduction catalysts.
abstract: A template-free approach based on the use of eutectic mixtures composed of 2-hydroxymethylthiophene and furfuryl alcohol has been designed for the preparation of hierarchical sulfur-doped carbons (SPCs) in monolithic form. The temperature used for carbonization, for example, 600, 800, or 900 °C, determined most of the physicochemical properties of the resulting SPCs. Thus, the surface area increased from below 400 to up 775 m(2)  g(-1) , along with the carbonization temperature, whereas the sulfur content decreased from approximately 15 to 5 wt %. The oxygen reduction reaction performance in samples carbonized at 900 °C was good, with the four-electron-transfer reaction prevailing over the two-electron-transfer one. Interestingly, the methanol tolerance and stability of these SPCs were also remarkable, with less than 5% current decrease immediately after methanol addition, whereas, in terms of stability, the current decrease was below 8 % after 20000 s. This performance was in the range of that found not only for other SPCs, but also for many nitrogen-doped and even some dual-doped (S and N) ones.
authors.affiliation: Instituto de Ciencia de Materiales de Madrid-ICMM, Consejo Superior de Investigaciones Científicas-CSIC, Campus de Cantoblanco, 28049-Madrid (Spain).
authors.forename: Nieves
authors.initials: N
authors.lastname: López-Salas
authors.forename: Francisco
authors.initials: F
authors.lastname: del Monte
authors.forename: Aitana
authors.initials: A
authors.lastname: Tamayo
authors.forename: José Luís G
authors.initials: JL
authors.lastname: Fierro
authors.forename: Antonio L
authors.initials: AL
authors.lastname: De Lacey
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Ferrer
authors.forename: María C
authors.initials: MC
authors.lastname: Gutiérrez
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D045424:Complex Mixtures; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013455:Sulfur / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D045424:Complex Mixtures; D013876:Thiophenes; D013455:Sulfur; D002244:Carbon; D010100:Oxygen
keywords: carbon; fuel cells; heterogeneous catalysis; oxygen reduction reaction; sulfur