NanoCOT: Low-Cost Nanostructured Electrode Containing Carbon, Oxygen, and Titanium for Efficient Oxygen Evolution Reaction

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• 作者：Zhichao Shan ; Panikar Sathyaseelan Archana ; Gang Shen ; Arunava Gupta ; Martin G. Bakker ; Shanlin Pan
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：September 23, 2015
• 年：2015
• 卷：137
• 期：37
• 页码：11996-12005
• 全文大小：715K
• ISSN：1520-5126

文摘

Developing high-efficiency, durable, and low-cost catalysts based on earth-abundant elements for the oxygen evolution reaction (OER) is essential for renewable energy conversion and energy storage devices. In this study, we report a highly active nanostructured electrode, NanoCOT, which contains carbon, oxygen, and titanium, for efficient OER in alkaline solution. The NanoCOT electrode is synthesized from carbon transformation of TiO₂ in an atmosphere of methane, hydrogen, and nitrogen at a high temperature. The NanoCOT exhibits enhanced OER catalytic activity in alkaline solution, providing a current density of 1.33 mA/cm² at an overpotential of 0.42 V. This OER current density of a NanoCOT electrode is about 4 times higher than an oxidized Ir electrode and 15 times higher than a Pt electrode because of its nanostructured high surface area and favorable OER kinetics. The enhanced catalytic activity of NanoCOT is attributed to the presence of a continuous energy band of the titanium oxide electrode with predominantly reduced defect states of Ti (e.g., Ti¹⁺, Ti²⁺, and Ti³⁺) formed by chemical reduction with hydrogen and carbon. The OER performance of NanoCOT can also be further enhanced by decreasing its overpotential by 150 mV at a current density of 1.0 mA/cm² after coating its surface electrophoretically with 2.0 nm IrO_x nanoparticles.