Phase-Controlled Synthesis of Pd–Se Nanocrystals for Phase-Dependent Oxygen Reduction Catalysis
Zhiyong Yu, Shulin Xu, Yonggang Feng, Chengyong Yang, Qing Yao, Qi Shao, Yafei Li, Xiaoqing Huang
Abstract
Searching for highly efficient oxygen reduction reaction (ORR) electrocatalysts for fuel cell technology, in which the crystal structure plays a powerful role in regulating the electrocatalysis, is urgent yet challenging. Herein, we have explored the active and stable Pd–Se alloy electrocatalysts with controlled phase toward alkaline ORR. The phase-controlled Pd–Se nanoparticles (NPs) show interesting phase-dependent electrocatalytic performance, in which the Pd17Se15 NPs/C exhibits much better ORR performance than its counterpart, Pd7Se4 NPs/C, and the commercial Pd/C and Pt/C. Based on the detailed analysis, Pd in Pd17Se15 possesses more Se atom coordination and a higher valence state, thus providing a stronger capacity for the absorption of oxygenated species. DFT further reveals more charge transfer from the Pd17Se15 surface to the *OOH intermediate, which is the reason for the activity enhancement.