Uniform PdH0.33 nanodendrites with a high oxygen reduction activity tuned by lattice H

We report the synthesis of β-palladium hydride nanodendrites (PdH0.33 NDs). The uniform PdH0.33 NDs are 36.3 ± 5.0 nm in diameter and selectively expose (111) planes decorated with (221) and (331) high-indexed steps. The PdH0.33 NDs show a high mass activity of 0.719 A/mgPd at 0.9 V (vs. reversible hydrogen electrode-RHE) toward alkaline oxygen reduction reaction (ORR), which is 3.7 and 6.3 times that of commercial Pt/C and house-made Pd/C, respectively. This study exemplifies the possibility of using special morphology and lattice H to modify the strain and electronic effect of metal for the optimization of functionalities. [Display omitted] •Synthesis of uniform PdH0.33 NDs with exposed (111) facets decorated with (221) and (331) high-indexed steps.•PdH0.33 NDs show an outstanding ORR activity in alkaline media.•DFT calculations suggest the ORR activity should be correlated to the incorporation of H atoms in the Pd matrix.