TY - JOUR
T1 - Electrochemical stability of RuO2(110)/Ru(0001) model electrodes in the oxygen and chlorine evolution reactions
AU - Goryachev, Andrey
AU - Etzi Coller Pascuzzi, Marco
AU - Carlà, Francesco
AU - Weber, Tim
AU - Over, Herbert
AU - Hensen, Emiel J.M.
AU - Hofmann, Jan Philipp
PY - 2020/3/10
Y1 - 2020/3/10
N2 - RuO
2 is commercially employed as an anodic catalyst in the chlor-alkali process. It is also one of the most active electrocatalysts for the oxidation of water, relevant to electrochemical water splitting. However, the use of RuO
2 is limited by its low anodic stability under acidic conditions, especially at high overpotentials. In the present work, the electrochemical stability of model RuO
2(110)/Ru(0001) anodes was investigated in order to gain a deeper understanding of the relation between structure and performance in Cl
2 and O
2 evolution reactions (CER and OER, respectively). Online electrochemical mass spectrometry was used to determine the onset potential of CER and OER in HCl and H
2SO
4 electrolytes, respectively. The onset potential of OER was higher in HCl than in H
2SO
4 due to competition with the kinetically more favorable CER. A detailed stability evaluation revealed pitting corrosion of the electrode surface with exposure of Ru(0001) metal substrate concomitant with the formation of a hydrous RuO
2 in some areas regardless of the applied electrochemical treatment. However, despite local pitting, the RuO
2(110) layer preserves its thickness in most areas. Degradation of the electrode was found to be less severe in 0.5 M HCl due to a decrease in the faradaic efficiency of RuO
2 oxidation caused by competition with the kinetically more favorable CER.
AB - RuO
2 is commercially employed as an anodic catalyst in the chlor-alkali process. It is also one of the most active electrocatalysts for the oxidation of water, relevant to electrochemical water splitting. However, the use of RuO
2 is limited by its low anodic stability under acidic conditions, especially at high overpotentials. In the present work, the electrochemical stability of model RuO
2(110)/Ru(0001) anodes was investigated in order to gain a deeper understanding of the relation between structure and performance in Cl
2 and O
2 evolution reactions (CER and OER, respectively). Online electrochemical mass spectrometry was used to determine the onset potential of CER and OER in HCl and H
2SO
4 electrolytes, respectively. The onset potential of OER was higher in HCl than in H
2SO
4 due to competition with the kinetically more favorable CER. A detailed stability evaluation revealed pitting corrosion of the electrode surface with exposure of Ru(0001) metal substrate concomitant with the formation of a hydrous RuO
2 in some areas regardless of the applied electrochemical treatment. However, despite local pitting, the RuO
2(110) layer preserves its thickness in most areas. Degradation of the electrode was found to be less severe in 0.5 M HCl due to a decrease in the faradaic efficiency of RuO
2 oxidation caused by competition with the kinetically more favorable CER.
KW - Chlorine evolution reaction
KW - Electrocatalysis
KW - Oxygen evolution reaction
KW - Ruthenium dioxide
KW - Stability
UR - http://www.scopus.com/inward/record.url?scp=85078078760&partnerID=8YFLogxK
U2 - 10.1016/j.electacta.2020.135713
DO - 10.1016/j.electacta.2020.135713
M3 - Article
SN - 0013-4686
VL - 336
JO - Electrochimica Acta
JF - Electrochimica Acta
M1 - 135713
ER -
