Transition-Metal Doping of Oxide Nanocrystals for Enhanced Catalytic Oxygen Evolution

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• 作者：Dong Myung Jang ; In Hye Kwak ; El Lim Kwon ; Chan Su Jung ; Hyung Soon Im ; Kidong Park ; Jeunghee Park
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 29, 2015
• 年：2015
• 卷：119
• 期：4
• 页码：1921-1927
• 全文大小：398K
• ISSN：1932-7455

文摘

Catalysts for the oxygen reduction and evolution reactions are central to key renewable-energy technologies including fuel cells and water splitting. Despite tremendous effort, the development of oxygen electrode catalysts with high activity at low cost remains a great challenge. In this study, we report a generalized sol鈥揼el method for the synthesis of various oxide nanocrystals (TiO₂, ZnO, Nb₂O₅, In₂O₃, SnO₂, and Ta₂O₅) with appropriate transition metal dopants for an efficient electrocatalytic oxygen evolution reaction (OER). Although TiO₂ and ZnO nanocrystals alone have little activity, all the Mn-, Fe-, Co-, and Ni-doped nanocrystals exhibit greatly enhanced OER activity. A remarkable finding is that Co dopant produces higher OER activity than the other doped metals. X-ray photoelectron and X-ray absorption spectroscopies revealed the highly oxidized metal ions that are responsible for the enhanced catalytic reactivity. The excellent OER activity of the Co-doped nanocrystals was explained by a synergistic effect in which the oxide matrix effectively guards the most active Co dopants at higher oxidation states by withdrawing the electrons from the metal dopants. The metal-doped NCs exhibit enhanced catalytic activity under visible light irradiation, suggesting their potential as efficient solar-driven OER photoelectrocatalysts.