Engineering Ultra‐Low Fe or Ni Loading in Polymer Derived SiCN(O) Fibre Mats: Exploring the Performance towards Alkaline OER

ABSTRACT In this study, Fe or Ni‐anchored silicon carbo(xy)nitride (SiCN(O)) fibre mats were synthesized via the polymer‐derived ceramics (PDC) approach to investigate their electrocatalytic performance toward alkaline OER. The resulting fibrous‐supported pre‐catalysts formed porous, interconnected networks with nanoscale distribution of catalytically active phases. The spectroscopy and microscopy investigations confirmed the successful incorporation of Fe 3 C or Ni nanocrystals within the SiCN(O) matrix and the presence of different binding modes of nitrogen species in the fibres. Electrochemical measurements showed that the Ni‐SiCN(O) compound achieved an overpotential of 460 mV at 10 mA cm −2 in 1 m KOH, for an ultra‐low Ni loading of only 0.01 mg cm −2 . While Ni‐based systems are inherently more active than Fe‐based ones for alkaline OER, the Ni‐SiCN(O) fibre mats demonstrated that even minimal Ni incorporation into the SiCN(O) matrix can result in efficient catalytic behaviour. In contrast, the Fe‐SiCN(O) catalyst exhibited lower activity, likely due to the formation of Fe 3 C and the absence of Fe‐N x coordination. This study highlights the potential of ultra‐low metal loading PDC for water electrolysis in alkaline media and underscores the importance of optimizing both metal dispersion and support interactions for improved OER performance.