TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compositions: The nitrogen-doped graphene further contains iron (Fe) and/or cobalt (Co) and optionally also at least one metal selected from manganese (Mn), nickel (Ni), vanadium (V), chromium (Cr), titanium (Ti), copper (Cu), platinum (Pt), palladium (Pd) and ruthenium (Ru) or any alloy, where Fe is present as Fe, iron(III) oxide (Fe2O3), iron(II,III) oxide (Fe3O4), iron(II) hydroxide (Fe(OH)2), iron(III) oxide-hydroxide (Fe(OH)3) and/or FeOOH and/or Co is present as Co, cobalt(II) hydroxide (Co(OH)2), cobalt(II,III) oxide (Co3O4) and/or CoO. The Fe, Co and/or any optionally present metal are present as small particles, preferably as nanoparticles. The nitrogen-doped graphene contains 1-15 wt.%, preferably 4-6 wt.% Fe, based on the total weight of the Fe-containing nitrogen-doped graphene. Preferred Process: In preparing nitrogen-doped graphene, step (i) is carried out in solution or dispersion. Step (ii) is carried out by: (ii.1) removing the solvent or dispersant from the mixture obtained in step (i); (ii.2) heating the solid obtained in step (ii.1) to 450-650 degrees C; and (ii.3) heating the solid obtained in step (ii.2) to 700-1100 degrees C. Alternatively, preparing nitrogen-doped graphene which further comprises Fe and/or Co and optionally also at least one metal selected from Mn, Ni, V, Cr, Ti, Cu, Pt, Pd and Ru, involves: (a) treating graphene oxide with a nitrogen-containing compound selected from cyanamide, dicyandiamide, melamine, melam, melem, melon, urea, ethylene diamine, ammonia, mixtures of these compounds and mixtures of these compounds with barbituric acid, cyanuric acid and/or cyanuric chloride, where step (a) is carried out in solution or dispersion; (b) removing the solvent or dispersant from the mixture obtained in step (a); (c) heating the solid obtained in step (b) to 450-650 degrees C; (d) adding Fe or and/or an Fe compound and/or Co and/or a Co compound and optionally also at least one metal selected from Mn, Ni, V, Cr, Ti, Cu, Pt, Pd, Ru or any alloy or a compound to the product obtained in step (c); and (e) heating the product obtained in step (d) to 700-1100 degrees C. Graphene oxide is first treated with a surfactant before it is subjected to step (i) or (a). In step (i) or (a), the nitrogen-containing compound is selected from cyanamide, dicyandiamide, mixtures of cyanamide with barbituric acid and/or cyanuric acid and mixtures of dicyandiamide with barbituric acid and/or cyanuric acid, and is in particular cyanamide. Preferred Aerogel: In using the aerogel, the electrode is an oxygen consumption electrode, in particular an oxygen consumption electrode for the electrolysis of hydrochloric acid or alkali metal chlorides. The electrode is a supercapacitor electrode. Preferred Electrode: The electrode further comprises an electrolyte which is preferably a polyvinyl alcohol (PVA)/sulfuric acid (H2SO4) gel, a PVA/phosphoric acid (H3PO4) gel, a PVA/potassium hydroxide (KOH) gel, a PVA/sodium hydroxide (NaOH) gel, a PVA/sodium sulfate (Na2SO4) gel or an ionic liquid polymer gel. The electrode is obtainable by cutting the aerogel into slices having a thickness of 0.5-1.5 mm and/or having a diameter of 5-15 mm. EXAMPLE - No suitable example given.