Hierarchical PdNi alloy nanochains coupled with Ni(OH) 2 nanosheets to enhance CO-poisoning resistance for the methanol oxidation reaction.

Hybridizing Pd-based electrocatalysts with Ni-based species has been recognized as an effective pathway to enhance the catalytic performance for the methanol oxidation reaction (MOR). However, doping Ni-based species with heterogeneous valences into Pd nanocrystals still remains challenging, although heterogeneous valence Ni species may result in improved properties of Pd from different aspects. Herein, a facile one-pot synthetic method is reported to simultaneously introduce alloyed Ni 0 into Pd lattices and couple hydroxy Ni 2+ species with a Pd surface, generating 1D porous PdNi alloy nanochains@Ni(OH) 2 nanosheet hybrids (PdNi NCs@Ni(OH) 2 NSs). Borane- tert -butylamine (C 4 H 14 BN) plays the key role in realizing the formation of Ni-based species with heterogeneous valence. On one hand, it works as a reducing agent to facilitate the doping of alloyed Ni 0 into the lattice of Pd nanochains. On the other hand, it raises the solution pH value and converts the remaining [Ni(CN) 4 ] 2- into Ni(OH) 2 nanosheets. Each component of the PdNi NCs@Ni(OH) 2 NSs plays an important role: Pd serves as the active site, alloyed Ni 0 modifies the electronic structure of Pd, and Ni(OH) 2 provides abundant OH ads species to strengthen the anti-poisoning capability, thus greatly enhancing the activity, CO-tolerance, and durability for the MOR.