Tailored Fabrication of Defect-Rich Ion Implanted CeO 2-x Nanoflakes for Electrochemical Sensing of H 2 O 2

• Published in: Journal of the Electrochemical Society 2023-05, Vol.170 (5), p.57519
• Main Authors: Luo, Yueyue, Zheng, Xiaoran, Vutukuri, Corey Venkata, Ho, Naomi, Atanacio, Armand J., Manohar, Madhura, Arandiyan, Hamidreza, Wang, Yuan, Sorrell, C.C., S. Mofarah, Sajjad, Koshy, Pramod
• Format: Article
• Language: English
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1945-7111/acd41f

As an alternative to H 2 O 2 enzymatic biosensing devices, non-enzymatic CeO 2 -based biosensors have shown improved sensibility, robustness, and shelf lives. The redox capability in CeO 2 and rapid switching between its oxidation states facilitate the formation of structural vacancy defects that serve as active sites. This work reports a novel approach for synthesis of defect-rich CeO 2-x -based nanoflakes using a controllable electrochemical-based deposition at low temperatures (45°−65 °C) followed by low-energy ion implantation. Among the nanoflakes, Mo-implanted CeO 2-x exhibited outstanding sensitivity of 4.96 × 10 −5 A·mM −1 cm −2 within the linear range of 0.05–10 mM. Moreover, the ion-implanted samples yielded high sensing stability and electronic conductivity. The former was achieved through the multi-valence charge transfer between Ce and the implanted ions that caused the reduction of Gibbs free energies required for the formation/retention of the defects. The latter was due to the narrowing of the electronic bandgap of CeO 2-x by creation of defect-induced midgap states.