Bifunctional Water Splitting Performance of NiFe LDH Improved by Pd2+ Doping

Nobel metal doping is an effective strategy to enhance the catalytic activity of electrocatalysts. Herein, a novel bifunctional electrocatalyst based on NiFe layered double hydroxide with ultra-low Pd2+ doping (NiFePd LDH) was constructed by a one-step hydrothermal method, where the Pd2+ is introduced by PdCl42-. The results show that Ni2+ and Pd2+ species are concomitantly deposited, and the slow-release introduction of Pd2+ improves the element uniform distribution and effectively affects the electronic structures of active species by inducing local defects and lattice distortions, which is beneficial for stimulating the catalytic activity of NiFePd LDH. Under the optimal hydrothermal time, NiFePd LDH-3 h only requires OER/HER overpotentials of 270 mV at 50 mA cm(-2)/-316 mV at -10 mA cm(-2), respectively, whose Tafel slopes are only 69.3/135.8 mV dec(-1). As a bifunctional catalyst, it achieves a low voltage of 1.74 V at 10 mA cm(-2) for overall water splitting with excellent long-term durability.