Enhanced hydrogen storage properties of ZrCo alloy decorated with flower-like Pd particles

ZrCo alloy prepared by arc-melting method was decorated by Pd particles with different PdCl2 concentrations of 0.2 g L−1, 0.6 g L−1, and 1.0 g L−1, respectively. The effects of Pd coating on the microstructures and hydrogen storage properties of ZrCo alloy were investigated systematically. The modified ZrCo alloy is coated with flower-shaped Pd particles which transform from angular cluster into rounded-edge stacking with increasing depositing concentration. The hydriding kinetic property of the Pd decorated alloys is greatly improved compared with the original alloy, which can be attributed to the catalytic effect of Pd combined with the spillover mechanism. The Pd decorated alloy with deposition concentration 0.2 g L−1 demonstrates superior hydriding kinetic property due to the high catalytic efficiency of the Pd particles with more surface area. Dehydriding test shows that the hydrogen desorption capacities of the modified samples increase with the increasing deposited concentration, which corresponds to the elevated desorption plateau and the decreased stability of the hydriding sample. In addition, the investigation on the cyclic stability of the samples shows that the catalyst effect of Pd is weakened at fifth cycle than that at first cycle, which could be related with the morphology change of Pd particles upon cycling.