Hydrogen evolution reaction kinetics on electrodeposited Pt-M (M = Ir, Ru, Rh, and Ni) cathodes for ammonia electrolysis

Ramasamy Palaniappan, David C. Ingram, Gerardine G. Botte

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Metallic and bimetallic electrocatalysts of the type PtxM 1-x (where M = Ru, Rh, Ir, Ni) electrodeposited on carbon fiber paper were evaluated as electrocatalysts for the hydrogen evolution reaction (HER) in an ammonia electrolytic cell. The addition of 1 M ammonia resulted in an increase in the HER overpotential for all electrocatalysts except Rh. The bimetallic electrocatalysts offer higher HER activity compared to metallic ones with the trend Pt-Ir > Pt-Rh > Pt-Ru > Pt-Ni. The enhanced activity of the bimetals is attributed to the synergistic activity. Ammonia adsorption is specific to the more electropositive alloying material, leaving the Pt sites active for hydrogen underpotential deposition and HER. Increasing the loading by a factor of two resulted in a decrease in the pore size thereby leading to a poor three-phase electrocatalyst, which in-turn causes a decrease in the HER electrocatalytic activity in the presence and absence of 1 M ammonia. Maximum electrocatalytic activity was achieved with a Pt-Ir electrocatalyst with a loading (Me / [Me + Pt]) of 13%, a Pt content of 68% and an intercrystallite distance of 7.2 nm.

Original languageEnglish
Pages (from-to)E12-E22
JournalJournal of the Electrochemical Society
Volume161
Issue number1
DOIs
StatePublished - 2014

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