Identifying the dynamic behaviors in complete reconstruction of Co-based complex precatalysts during electrocatalytic oxygen evolution
Zhang Jingfang, Wu Danyang, Cai Linke, Lu Youluan, Cheng Fanpeng, Shi Lijuan, Yi Qun*, Liu Yao*, Huang Yi*
DOI:10.1016/j.jechem.2024.08.043
Abstract
Transition metal-based nanomaterials have emerged as promising electrocatalysts for oxygen evolution reaction (OER). Considerable research efforts have shown that self-reconstruction occurs on these nano materials under operating conditions of OER process. However, most of them undergo incomplete reconstruction with limited thickness of reconstruction layer, leading to low component utilization and arduous exploration of real catalytic mechanism. Herein, we identify the dynamic behaviors in complete reconstruction of Co-based complexes during OER. The hollow phytic acid (PA) cross-linked CoFe-based complex nanoboxes with porous nanowalls are designed because of their good electrolyte penetration and mass transport ability, in favor of the fast and complete reconstruction. A series of experiment characterizations demonstrate that the reconstruction process includes the fast substitution of PA by OH to form Co(Fe)(OH)x and subsequent potential-driven oxidation to Co(Fe)OOH. The obtained CoFeOOH delivers a low overpotentiaof 290 mV at a current density of 10 mA cm-2 and a long-term stability. The experiment results together with theory calculations reveal that the Fe incorporation can result in the electron rearrangement of reconstructed CoFeOOH and optimization of their electronic structure, accounting for the enhanced OER activity. The work provides new insights into complete reconstruction of metal-based complexes during OER and offers guidelines for rational design of high-performance electrocatalysts.
過渡金屬基納米材料是一種很有前途的析氧反應電催化劑。大量的研究表明，在OER工藝條件下，這些納米材料發生了自重構。然而，它們大多是不完全重構，重構層厚度有限，導緻組分利用率低，對真正催化機理的探索困難。本文研究了钴基配合物在OER過程中完全重構的動力學行為。由于具有良好的電解質滲透能力和質量傳遞能力，設計了具有多孔納米壁的中空植酸（PA）交聯cofe基複合納米盒，有利于快速和完全的重建。一系列實驗表征表明，重構過程包括：PA被OH快速取代生成Co(Fe)(OH)x，随後電位驅動氧化生成Co(Fe)OOH。獲得的CoFeOOH在電流密度為10 mA cm-2時具有290 mV的低過電位，并且具有長期穩定性。實驗結果和理論計算表明，Fe的摻入導緻重構CoFeOOH的電子重排和電子結構的優化，是OER活性增強的原因。這項工作為金屬基配合物在OER過程中的完全重構提供了新的見解，并為高性能電催化劑的合理設計提供了指導。
