Theoretical prediction by DFT and experimental observation of heterocation-doping effects on hydrogen adsorption and migration over the CeO2(111) surface

Kota Murakami; Yuta Mizutani; Hiroshi Sampei; Atsushi Ishikawa; Yuta Tanaka; Sasuga Hayashi; Sae Doi; Takuma Higo; Hideaki Tsuneki; Hiromi Nakai; Yasushi Sekine

doi:10.1039/d0cp05752e

Theoretical prediction by DFT and experimental observation of heterocation-doping effects on hydrogen adsorption and migration over the CeO₂(111) surface

Phys Chem Chem Phys. 2021 Feb 28;23(8):4509-4516. doi: 10.1039/d0cp05752e. Epub 2021 Feb 1.

Authors

Kota Murakami¹, Yuta Mizutani, Hiroshi Sampei, Atsushi Ishikawa, Yuta Tanaka, Sasuga Hayashi, Sae Doi, Takuma Higo, Hideaki Tsuneki, Hiromi Nakai, Yasushi Sekine

Affiliation

¹ Applied Chemistry, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555, Japan. ysekine@waseda.jp.

PMID: 33523062
DOI: 10.1039/d0cp05752e

Abstract

Hydrogen (H) atom adsorption and migration over the CeO₂-based materials surface are of great importance because of its wide applications to catalytic reactions and electrochemical devices. Therefore, comprehensive knowledge for controlling the H atom adsorption and migration over CeO₂-based materials is crucially important. For controlling H atom adsorption and migration, we investigated irreducible divalent, trivalent, and quadrivalent heterocation-doping effects on H atom adsorption and migration over the CeO₂(111) surface using density functional theory (DFT) calculations. Results revealed that the electron-deficient lattice oxygen (O_lat) and the flexible CeO₂ matrix played key roles in strong adsorption of H atoms. Heterocations with smaller valence and smaller ionic radius induced the electron-deficient O_lat. In addition, smaller cation doping enhanced the CeO₂ matrix flexibility. Moreover, we confirmed the influence of H atom adsorption controlled by doping on surface proton migration (i.e. surface protonics) and catalytic reaction involving surface protonics (NH₃ synthesis in an electric field). Results confirmed clear correlation between H atom adsorption energy and surface protonics.