We reported the synthesis and characterization of the novel and less explored methanol-functionalized Sulphur-Doped Ordered Mesoporous Carbon Hollow Spheres (S-HWf) as metal-free electrocatalyst for the Oxygen Reduction Reaction (ORR) in alkaline media. The S-HWf was synthetized by the silica template-based method, using resorcinol and formaldehyde as carbon source. The doping was made in situ using 2-thiophenemethanol as sulphur source. The functionalization was carried out with methanol solution (0.5 mol L^-1) with the aid of intermittent microwave heating. The catalytic activity of S-HWf was compared with that of non-doped Ordered Mesoporous Carbon Hollow Spheres (HW) synthetized by the same method.

The morphology of S-HWf and HW analyzed in a Field Emission-Scanning Electron Microscope (FE-SEM) resulted in rough hollow spheres. The diameter and wall thickness were ~304 and ~90 nm for HW, while for S-HWf were ~248 and ~50 nm, respectively. The use of 2-thiophenemethanol as dopant, had an important effect in the morphology. The chemical surface composition determined by X-ray Photoelectron Spectroscopy (XPS) included the presence of C, O, and Si for HW. In addition to these elements, S was also detected at S-HWf (0.4 at. %). The textural properties were determined by N₂ adsorption/desorption measurements. S-HWf and HW showed a surface area of 1007 and 505 m² g^-1, respectively, with micro-mesoporosity. Analysis of the electrocatalysts by X-Ray Diffraction (XRD) showed their amorphous structure with low-intensity crystalline phases. Meanwhile, from Raman spectroscopy S-HWf exhibited better ordering in its structure due to a lower value in I_D/I_G the intensity ratio compared to HW. The catalytic activity of the electrocatalysts for the ORR was evaluated by Rotating-Ring Disc Electrode (RRDE) technique. S-HWf showed a higher performance than HW, with an onset potential of 0.88 V half-wave potential 0.81 V and a current density (j) of -1.49 mA cm^-2 at 0.8 V (all potentials vs. RHE). Moreover, its electron transfer number was n= 3.9 with a H₂O₂ production of ~3%. Furthermore, after accelerated degradation tests (3000 cycles, between 0.6 and 1.0 V), S-HWf showed an improvement in catalytic activity with onset potential of 0.88 V, half-wave potential of 0.82 V and j= -1.69 mA cm^-2 at 0.8 V. Also, its n was 3.9 with a production of H₂O₂ of ~2%.

In this study it was found that doping with sulphur and functionalizing with methanol have a positive effect on the catalytic activity for the ORR and the electrochemical stability of Ordered Mesoporous Carbon Hollow Spheres. The electrochemical behavior of the S-HWf electrocatalyst indicated that it is a potential candidate for Anion Exchange Membrane Fuel Cells (AEMFC) cathode applications.