Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
Chemical and Petroleum Engineering, and Physics, University of Pittsburgh , Pittsburgh, Pennsylvania 15261, United States.
J Am Chem Soc. 2017 Jan 25;139(3):1077-1080. doi: 10.1021/jacs.6b12529. Epub 2017 Jan 17.
Electrocatalytic water splitting to produce hydrogen comprises the hydrogen and oxygen evolution half reactions (HER and OER), with the latter as the bottleneck process. Thus, enhancing the OER performance and understanding the mechanism are critically important. Herein, we report a strategy for OER enhancement by utilizing gold nanoclusters to form cluster/CoSe composites; the latter exhibit largely enhanced OER activity in alkaline solutions. The Au/CoSe composite affords a current density of 10 mA cm at small overpotential of ∼0.43 V (cf. CoSe: ∼0.52 V). The ligand and gold cluster size can also tune the catalytic performance of the composites. Based upon XPS analysis and DFT simulations, we attribute the activity enhancement to electronic interactions between nanocluster and CoSe, which favors the formation of the important intermediate (OOH) as well as the desorption of oxygen molecules over Au/CoSe composites in the process of water oxidation. Such an atomic level understanding may provide some guidelines for design of OER catalysts.
电催化水分解制氢包括析氢和析氧半反应（HER 和 OER），后者是瓶颈过程。因此，提高 OER 性能和理解其机制至关重要。在此，我们报告了一种通过利用金纳米团簇形成团簇/CoSe 复合材料来增强 OER 的策略；后者在碱性溶液中表现出极大增强的 OER 活性。Au/CoSe 复合材料在小过电势下提供了 10 mA cm 的电流密度，约为 0.43 V（相比 CoSe：约 0.52 V）。配体和金团簇的尺寸也可以调节复合材料的催化性能。基于 XPS 分析和 DFT 模拟，我们将活性增强归因于纳米团簇和 CoSe 之间的电子相互作用，这有利于重要中间体（OOH）的形成以及在水氧化过程中氧气分子在 Au/CoSe 复合材料上的脱附。这种原子水平的理解可能为 OER 催化剂的设计提供一些指导。
