Topological Type‐II Dirac Semimetal and Superconductor PdTe₂ for Ethanol Electrooxidation

Abstract

Ethanol oxidation reaction (EOR) is an essential half reaction in direct ethanol fuel cells (DEFCs). Pd‐based materials are ideal candidates for electrocatalytic EOR. However, most reported materials generally show low ethanol oxidation completeness ( J f / J b ). Herein, an EOR electrocatalyst with high J f / J b is documented: topological type‐II Dirac semimetal and superconductor PdTe 2 . It is demonstrated that bulk PdTe 2 can be successfully exfoliated into nanosheets with ≈4 nm thickness, by liquid‐phase exfoliation, which are loaded onto carbon fiber paper as EOR electrocatalysts. The resulting PdTe 2 nanosheet electrocatalyst shows fivefold mass activity compared to that of commercial Pd black. In addition, the ratio of forward current ( J f ) to backward current ( J b ) of PdTe 2 nanosheets is 5.28, which is much higher than previously reported ( J f / J b ≈ 2), indicating excellent oxidation completeness of ethanol. Moreover, PdTe 2 nanosheets exhibit a rather low Tafel slope of 41.2 mV dec −1 as well as good stability without reduction after 2 h of chronoamperometry measurement. These outstanding results indicate that the PdTe 2 nanosheet is a promising electrocatalyst material for high‐performance energy conversion.