Exploring efficient alkaline hydrogen oxidation reaction
(HOR)
electrocatalysts is of great concern for constructing anion exchange
membrane fuel cells (AEMFCs). Herein, d-band center modulated PdCo
alloys with ultralow Pd content anchored onto the defective carbon
support (abbreviated as PdCo/NC hereafter) are proposed as highly
efficient HOR catalyst. The as-prepared catalyst exhibits exceptional
HOR performance compared to the Pt/C catalyst, achieving thermodynamically
spontaneous and kinetically preferential reactions. Specifically,
the resultant PdCo/NC demonstrates a marked enhancement in alkaline
HOR performance, with the highest mass and specific activities of
1919.6 mA mgPd
–1 and 1.9 mA cm–2, 51.1 and 4.2 times higher than those of benchmark of Pt/C, along
with an excellent stability in a chronoamperometry test. In the analysis
of in situ Raman spectra, it was discovered that
tetrahedrally coordinated H-bonded water molecules were formed during
the HOR process. This indicates that the promotion of interfacial
water molecule formation and enhancement of HOR activities in PdCo/NC
are facilitated by defect engineering and the turning of d-band center
in PdCo alloy. The essential knowledge obtained in this study could
open up a new direction for modifying the electronic structure of
cost-effective HOR catalysts through electronic structure engineering.