Heterogeneous Electrocatalytic Oxygen Evolution Reaction by a Sol‐Gel Electrode with Entrapped Na 3 [Ru 2 ( μ ‐CO 3 ) 4 ]: The Effect of NaHCO 3

• Published in: Chemphyschem 2023-11, Vol.24 (22)
• Main Authors: Aharon, Shiran, Patra, Shanti Gopal, Meyerstein, Dan, Tzur, Eyal, Shamir, Dror, Albo, Yael, Burg, Ariela
• Format: Article
• Language: English
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.202300517

The Na 3 [Ru 2 ( μ ‐CO 3 ) 4 ] complex is acting as a water oxidation catalyst in a homogeneous system. Due to the significance of heterogeneous systems and the effect of bicarbonate on the kinetic, we studied the bicarbonate effect on the heterogeneous electrocatalyst by entrapping the Na 3 [Ru 2 ( μ ‐CO 3 ) 4 ] complex in a sol‐gel matrix. We have developed two types of sol‐gel electrodes, which differ by the precursor, and are demonstrating their stability over a minimum of 200 electrochemical cycles. The pH increases affected the currents and k cat for both types of electrodes, and their hydrophobicity, which was obtained from the precursor type, influenced the electrocatalytic process rate. The results indicate that NaHCO 3 has an important role in the catalytic activity of the presented heterogeneous systems; without NaHCO 3 , the diffusing species is probably OH − , which undergoes diffusion via the Grotthuss mechanism. To the best of our knowledge, this is the first study to present a simple and fast one‐step entrapment process for the Na 3 [Ru 2 ( μ ‐CO 3 ) 4 ] complex by the sol‐gel method under standard laboratory conditions. The results contribute to optimizing the WSP, ultimately helping expand the usage of hydrogen as a green and more readily available energy source.