Regulation of Transition Metal Doping into Double Perovskite Structure as for a Electrocatalyst in Water Electrolysis

Applying and combining of transition metals to perovskite structure is significantly dealt for improving the electrochemical property. The introduction of transition metals in the active B-site is considered as a useful pathway to regulate the chemical and electronic properties of the perovskites. In this study, a double perovskite structure (A 2 BB’O 6 ) is designed to apply large ionic radius elements such as tungsten(W) that can not be doped into the general single perovskite structure(ABO 3 ). Tungsten is normally equilibrium in the metallic phase, but tungsten ions rapidly move from 4 + state to the 6 + state in the oxide phase, boosting the electrochemical property. The W-based double perovskite materials are synthesized by a high temperature solid-state method. With a combination of Calcium (Ca) doped in the B-site for structural stabilization, transition metals (Ni, Co, etc.) are doped together as an active site to enhance the electrochemical performance. To analyze the physical and chemical structural characteristics, XRD with Rietveld refinement, XPS and XANES/EXAFS measurements are used. Rotating Disk Electrode (RDE) system is utilized to confirm the electrochemical performance of the prepared samples. Through cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurements, oxygen involved reactions are carried out to prove possibility on our W-based double perovskite materials as a high performance oxygen electrocatalyst with low-price.