23:T430,Abstract Development of metal‐free carbon‐based electrocatalysts for reducing oxygen to water (ORR), preferentially following a 4 electron transfer pathway, is of high importance. We present a two‐step synthesis of N‐doped carbon‐based ORR electrocatalysts by using an efficient thermal treatment of hydrothermally carbonized cellulose in ammonia combining devolatilization, reduction and nitrogen doping. The influence of the synthesis temperature as well as of the ammonia concentration used during the synthesis on the electrocatalytic ORR activity was analyzed using bulk‐ and surface‐sensitive techniques. Correlation of electrocatalytic activity with structural features of the catalysts provided deeper mechanistic understanding and enabled us to optimize the synthesis conditions. The nitrogen‐doped metal‐free catalyst originating from the treatment in 100 % NH 3 at 800 °C achieved a current density of −1 mA cm −2 at 0.83 V vs. RHE positioning it among the most active noble‐metal free and biomass‐based ORR catalysts reported so far.24:T552,The doping of SiO₂ and Fe₂O₃ into hydrochars that were produced by the hydrothermal carbonization of cellulose was studied with respect to its impact on the resulting surface characteristics and sorption behavior of CO₂, CH₄, and O₂. During pyrolysis, the structural order of the Fe-doped char changed, as the fraction of highly ordered domains increased, which was not observed for the undoped and Si-doped chars. The Si doping had no apparent influence on the oxidation temperature of the hydrochar in contrast to the Fe-doped char where the oxidation temperature was reduced because of the catalytic effect of Fe. Both dopants reduced the micro-, meso- and macroporous surface areas of the chars, although the Fe-doped chars had larger meso- and macroporosity than the Si-doped char. However, the increased degree in the structural order of the carbon matrix of the Fe-doped char reduced its microporosity relative to the Si-doped char. The adsorption of CO₂ and CH₄ on the chars at temperatures between 273.15 and 423.15 K and at pressures up to 115 kPa was slightly inhibited by the Si doping but strongly suppressed by the Fe doping. For O₂, however, the Si doping promoted the observed adsorption capacity, while Fe doping also showed an inhibiting effect.

#	Concept	H-Index	Publications	Citations
1	Engineering	4	4	81
2	Chemical Engineering	4	4	81
3	Chemistry	4	4	81
4	Catalysis	4	4	81
5	Materials Science	3	3	66

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