School of Advanced Materials, Shenzhen Graduate School, Peking University , Shenzhen 518055, P. R. China.
ACS Appl Mater Interfaces. 2017 May 17;9(19):16159-16167. doi: 10.1021/acsami.7b01591. Epub 2017 May 8.
CoO quantum dots (CoO-QDs) with a crystallite size of approximately 2 nm and oxygen vacancies were fabricated through multicycle lithiation/delithiation of mesoporous CoO nanosheets. Used as an oxygen evolution reaction (OER) electrocatalyst for water splitting, the catalytic performance (an overpotential of 270 mV@10 mA cm and no decay within 30 h) of CoO-QDs is superior to that of previously reported Co-based catalysts and the state-of-the-art IrO. Compared to that of the CoO nanosheets, the enhanced OER activity of CoO-QDs is attributed to two factors: one is the increased quantity of the Faradaic active sites, including the total active sites (q*), the most accessible active sites (q*), and their ratio (q*/q*); the other is the enhanced intrinsic electroactivity per active site evaluated by the turnover frequency and the current density normalized by the most accessible active sites (j/q*) related to the OER. This multicycle lithiation/delithiation method can be applied to other transition metal oxides as well, offering a general approach to develop high-performance electrocatalysts for water splitting.
通过介孔 CoO 纳米片的多周期锂化/脱锂反应，制备出了具有约 2nm 晶粒尺寸和氧空位的 CoO 量子点（CoO-QDs）。将 CoO-QDs 用作析氧反应（OER）电催化剂进行水分解时，其催化性能（在 10 mA cm 时的过电位为 270 mV，30 h 内没有衰减）优于以前报道的 Co 基催化剂和最先进的 IrO。与 CoO 纳米片相比，CoO-QDs 增强的 OER 活性归因于两个因素：一是增加了法拉第活性位点的数量，包括总活性位点（q*）、最易接近的活性位点（q*）及其比值（q*/q*）；二是通过与 OER 相关的周转频率和最易接近的活性位点（j/q*）归一化的电流密度评估的每个活性位点的增强的本征电活性。这种多周期锂化/脱锂方法也可以应用于其他过渡金属氧化物，为开发用于水分解的高性能电催化剂提供了一种通用方法。
