Optimal dopant selection forwater splitting with cerium oxides: Mining and screening first principles data

Abstract

We propose a powerful screening procedure, based on first principles computations and data analysis, to systematically identify suitable dopants in an oxide for the thermochemical water splitting process. The screening criteria are inspired by Sabatier’s principle, and are based on requirements placed on the thermodynamics of the elementary steps. Ceria was chosen as the parent oxide. Among the 33 dopants across the periodic table considered, Sc, Cr, Y, Zr, Pd and La are identified to be the most promising ones. Experimental evidence exists for the enhanced activity of ceria for water splitting when doped with Sc, Cr and Zr. The surface oxygen vacancy formation energy is revealed as the primary descriptor correlating with enhanced water splitting performance, while the dopant oxidation state in turn primarily governs the surface oxygen vacancy formation energy. The proposed screening strategy can be readily extended for dopant selection in other oxides for different chemical conversion processes (e.g., CO2 splitting, chemical looping, etc.).