Pt-Mediated Interface Engineering Boosts the Oxygen Reduction Reaction Performance of Ni Hydroxide-Supported Pd Nanoparticles
Dinesh Bhalothia, Che Yan, Nozomu Hiraoka, Hirofumi Ishii, Yen‐Fa Liao, Po‐Chun Chen, Kuan‐Wen Wang, Jyh‐Pin Chou, Sheng Dai, Tsan‐Yao Chen
Abstract
Fuel cells are considered potential energy conversion devices for utopia; nevertheless, finding a highly efficacious and economical electrocatalyst for the oxygen reduction reaction (ORR) is of great interest. By keeping this in view, we have proposed a novel design of a trimetallic nanocatalyst (NC) comprising atomic Pt clusters at the heterogeneous Ni(OH) 2 -to-Pd interface (denoted NPP-70). The as-prepared material surpasses the commercial J.M.-Pt/C (20 wt %) catalyst by ∼ 166 and ∼19 times with exceptionally high specific and mass activities of 16.11 mA cm –2 and 484.8 mA mg Pt –1 at 0.90 V versus reversible hydrogen electrode (RHE) in alkaline ORR (0.1 M KOH), respectively. On top of that, NPP-70 NC retains nearly 100% performance after 10k accelerated durability test (ADT) cycles. The results of physical characterization and electrochemical analysis confirm that atomic-scale Pt clusters induce strong lattice strain (compressive) at the Ni(OH) 2 -to-Pd interface, which triggers the electron relocation from Ni to Pt atoms. Such charge localization is vital for O 2 splitting on surface Pt atoms, followed by the relocation of OH – ions from the Pd surface. Besides, a sharp fall down in ORR performance (mass activity is 37 mA mg Pt –1 at 0.90 V versus RHE) is observed when the Pt clusters are decorated on the surface of NiO x and Pd (denoted NPP-RT). In situ partial fluorescence yield mode X-ray absorption spectroscopy (PFY-XAS) was employed to reveal the ORR pathways on both configurations. The obtained results demonstrate that interface engineering can be a potential approach to boost the electrocatalytic activity of metal hydroxide/oxide-supported Pd nanoparticles and in turn allow Pd to be a promising alternative for commercial Pt catalysts.