Delicate excavated trimetallic Prussian blue analogues for efficient oxygen evolution reactions. (10th March 2019)

• Record Type: Journal Article
• Authors: Liu, Jie; Wei, Shuting; Li, Ningbo; Zhang, Lei; Cui, Xiaoqiang
• Is Part Of: Electrochimica acta. Volume 299(2019)
• Page Start: 575
• Page End: 581
• Publication Date: 2019-03-10
• Subjects: Trimetallic electrocatalysts -- Prussian blue analogues -- Metal-organic frameworks -- Oxygen evolutionreaction; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.01.003
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Efficiently modulating the pore size, electrochemical conductivity and metal ratio of metal-organic frameworks (MOFs) is essential for improving their electrochemical catalytic activity. Herein, we develop a convenient strategy for excavating Prussian blue analogues (PBA) by using sodium sulfide (Na2 S) as a delicate digger to modulate the pore size and metal ratio while maintaining the MOFs feature. A subsequent anneal at 300 °C removes cyanide groups and induces a collapse of the PBA structure that leads to an increase in the Fe valence and conductivity. These delicate excavated PBA catalysts exhibited high activity for the oxygen evolution reaction (OER) with a low overpotential of 261 mV at 10 mA cm −2 and a small Tafel slope of 38 mV dec −1, which exceeded that obtained for commercial IrO2 in alkaline solution. This work may reveal a promising new method for exploring efficient MOFs-based electrocatalysts. Graphical abstract: Trimetallic Prussian blue analogue-based metal-organic frameworks with a uniform size of ∼90 nm were synthesized by a delicate excavating modulation. The modulated samples show excellent activity for the oxygen evolution reaction.Image 1 Highlights: Prussian blue analogues (PBA) were delicately excavated by using sodium sulfide etching and subsequent annealing to PBA-SA. This synthesized catalysts showed significant OER activity with a very low overpotential and a small Tafel slope. The high performances are attributed to the synergistic effect, accelerated electrolyte diffusion and increased conductivity.