Direct Formic Acid Electro-Oxidation on Pt Doped and Undoped La1-xSrxCoO3: Activity Suppression due to Proton Reduction Reaction. Issue 14 (1st January 2018)

• Record Type: Journal Article
• Authors: Bisht, Anuj; Sharma, Sudhanshu
• Is Part Of: Journal of the Electrochemical Society. Volume 165:Issue 14(2018)
• Page Start: H927
• Page End: H931
• Publication Date: 2018-01-01
• Subjects: Electrocatalysis; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0011814jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Combustion synthesized Pt-doped and undoped La1-x Srx CoO3 are utilized for formic acid electro-oxidation. Cyclic-voltammetry (CV) during formic acid electro-oxidation demonstrates that the oxidation current initially increases and then decays to zero on both the catalysts. This implies that the HCOOH possibly has some poisoning effect on the catalysts. Both materials show a unique reduction peak in the oxidation scan right after the addition of HCOOH in the electrolyte, demonstrating a reduction process in the oxidation cycle. When HCOOH is replaced by potassium formate, the reduction peak is found absent. Further, significant increase in the current is observed in the case of La1-x Srx CoO3 . This confirms that the protons which are generated during the electro-oxidation of HCOOH are reduced on the catalyst's surface generating the reduction peak in the CV. This process suppresses the counter-reaction to diminish the current. Instead of protons, K + ions are generated with potassium formate which greatly prevents the proton reduction reaction and leads to the formate ion oxidation. Only CO2 was evolved during the electro-oxidation which was confirmed through gas chromatography. Further investigations reveal that apart from proton reduction reaction, Pt-doped La1-x Srx CoO3 gets poisoned in presence of CO2 also; the main oxidation product of both HCOOH and KCOOH.