Electrocatalytic Activity of Some Cobalt Based Sodium Phosphates in Alkaline Solution

Dwibedi, D and Gond, R and Sada, K and Senthilkumar, B and Barpanda, P (2018) Electrocatalytic Activity of Some Cobalt Based Sodium Phosphates in Alkaline Solution. In: MRS Advances, 3 (22). pp. 1215-1220.

PDF MRS_ADV_3-22_1215-1220_2018.pdf - Published Version Restricted to Registered users only Download (1MB) | Request a copy

Abstract

The development of efficient water oxidation catalyst is a major path to realize water splitting systems, which could benefit high performance and cost-effective metal-Air batteries, fuel cells and solar energy conversion. To date, the rare crustal abundant platinum group metals rule this sector with Pt-Alloys being the best for oxygen reduction reaction (ORR) and ruthenium oxides for oxygen evolution reaction (OER) in acidic solution. However, they show poor stability and are too expensive for large scale applications. Moreover, oxygen reduction in basic solutions can otherwise be catalysed by metal oxide with non-precious earth abundant transition metals (e.g. Fe, Co, Ni). Hence, there is a massive demand to explore noble metal free bifunctional electrocatalysts. In this work, we present the electrocatalytic activity of three cobalt based sodium phosphates namely NaCoPO4 (with one phosphate), Na2CoP2O7 (with two phosphate) NaFe2Co(PO4)3 (with three phosphate). Synthesized by solution combustion route, all these phosphates confirmed phase purity. NaCoPO4 and Na2CoP2O7 adopted orthorhombic structure with Pnma and Pna21 space group respectively; whereas NaFe2Co(PO4)3 crystallized in monoclinic (C2/c) framework. Electrocatalytic activity of these cobalt phosphates were inspected by linear sweep voltammetry with rotating disk electrode (RDE). All three showed promising bifunctional activity. In fact, the ORR activities of both orthorhombic cobalt phosphates are comparable to Vulcan carbon and Pt/C. OER activity of Na2CoP2O7 overrode other phosphates. The bifunctional activity and good stability of these sodium cobalt phosphates stem from cobalt ions and stabilization of the catalytic centres by the phosphate frameworks. The present work builds a detail structure-property correlation in these phosphate systems and also demonstrates the possibility of utilizing these sodium cobalt phosphates as alternate cost-effective, novel electrocatalysts for efficient OER/ORR activity in alkaline solution.

Item Type:	Journal Article
Publication:	MRS Advances
Publisher:	Materials Research Society
Additional Information:	The copyright for this article belongs to the Materials Research Society
Keywords:	Catalyst activity; Catalytic oxidation; Cobalt compounds; Combustion synthesis; Cost effectiveness; Electrocatalysts; Electrolytic reduction; Energy conversion; Fuel cells; Iron compounds; Oxidation; Oxygen; Phosphates; Platinum alloys; Platinum metals; Precious metals; Rotating disks; Ruthenium compounds; Secondary batteries; Solar energy; Stabilization, Bifunctional electrocatalysts; catalytic; Electrocatalytic activity; Linear sweep voltammetry; Oxygen evolution reaction; Oxygen reduction reaction; Structure-property correlation; Water oxidation catalysts, Sodium compounds
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	24 Aug 2022 05:33
Last Modified:	24 Aug 2022 05:33
URI:	https://eprints.iisc.ac.in/id/eprint/76081

Actions (login required)

View Item