Oxygen Vacancy Injection on (111) CeO2 Nanocrystal Facets for Efficient H2O2 Detection

Abstract

Facet and defect engineering have achieved great success in improving the catalytic performance of CeO2, but the inconsistent reports on the synergistic effect of facet and oxygen vacancy and the lack of investigation on the heavily doped oxygen vacancy keeps it an attractive subject. Inspired by this, CeO2 nanocrystals with selectively exposed crystalline facets (octahedron, cube, sphere, rod) and abundant oxygen vacancies have been synthesized to investigate the synergistic effect of facet and heavily doped oxygen vacancy. The contrasting electrochemical behavior displayed by diverse reduced CeO2 nanocrystals verifies that oxygen vacancy acts distinctly on different facets. The thermodynamically most stable CeO2 octahedron enclosed by heavily doped (111) facets surprisingly exhibited the optimum non-enzymatic H2O2 sensing performance, with a high sensitivity (128.83 µA mM−1 cm−2), a broad linear range (20 µM~13.61 mM), and a low detection limit (1.63 µM). Meanwhile, the sensor presented satisfying selectivity, repeatability, stability, as well as its feasibility in medical disinfectants. Furthermore, the synergistic effect of facet and oxygen vacancy was clarified by the inclined distribution states of oxygen vacancy and the electronic transmission property. This work enlightens prospective research on the synergistic effect of alternative crystal surface engineering strategies.

Plasma-Engineered CeOx Nanosheet Array with Nitrogen-Doping and Porous Architecture for Efficient Electrocatalysis

“…CeO 2 , as a common transition metal oxides catalyst, has two distinctive characteristics: one is that CeO 2 prepared by conventional methods usually has a certain amount of oxygen vacancies (OVs), and the other is the flexible and reversible conversion between Ce 3+ and Ce 4+ oxidation states [ 10 ]. These two characteristics are conducive to achieving better electrocatalytic performance, but the low concentration of naturally generated Ce 3+ and OVs always restrict the performance improvement of CeO 2 -based electrocatalysts [ 11 ]. Considering the heterogeneous reactions that take place on the surface of active materials, surface engineering has been applied as a popular approach to boost the catalytic activity of CeO 2 [ 10 , 12 , 13 , 14 , 15 ].…”