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Sandra Möller, Stefan Barwe, Stefan Dieckhöfer, Justus Masa, Corina Andronescu, Wolfgang Schuhmann

• Carbon is a frequently used electrode material and an important additive in catalyst films. Its corrosion is often reported during electrocatalysis at high anodic potentials, especially in acidic electrolyte. Investigation of the carbon corrosion in alkaline environment is difficult due to the CO\(_{2}\)/CO\(_{3}\)\(^{2}\)− equilibrium. We report the on-line determination of electrolysis products generated on Ni\(_{x}\)B/C hybrid electrocatalysts in alkaline electrolyte at anodic potentials using differential electrochemical mass spectrometry (DEMS). Ni\(_{x}\)B/C catalyst films were obtained from mixtures containing different ratios of NiXB and benzoxazine monomers followed by polymerization and pyrolysis. The impact of the composition of the electrocatalyst on the dominant electrolysis process allows to distinguish between the oxygen evolution reaction and carbon corrosion using DEMS results as well as the catalyst surface composition evaluated from X-ray photoelectron spectra. At the imposed highly oxidative conditions, an increasing amount of Ni\(_{x}\)B in the electrocatalyst leads to a suppression of carbon corrosion.