Positive self-reconstruction in an FeNiMo phosphide electrocatalyst for enhanced overall water splitting. Issue 22 (19th October 2021)

• Record Type: Journal Article
• Authors: Wei, Yi; Shin, Cheol-Hwan; Gyan-Barimah, Caleb; Tetteh, Emmanuel Batsa; Park, Gisang; Yu, Jong-Sung
• Is Part Of: Sustainable energy & fuels. Volume 5:Issue 22(2021)
• Page Start: 5789
• Page End: 5797
• Publication Date: 2021-10-19
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/d1se01541a
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : Binder-free FeNiMoP synthesized by a simple two-step method shows interesting structural self-reconstruction and demonstrates remarkably high electrocatalytic overall water splitting performance in alkaline conditions. Abstract : Searching for low-cost and highly active bifunctional electrocatalysts toward hydrogen/oxygen evolution reactions is a grand challenge for water splitting hydrogen production. Herein, we prepare a trimetallic nickel, iron, and molybdenum phosphide (FeNiMoP) grown on nickel foam (NF) via a facile two-step process and employ it as a bifunctional electrocatalyst for full water splitting. In virtue of the superior hydrogen/oxygen evolution activity, the cell with the bifunctional FeNiMoP as both anode and cathode exhibits an initial low cell voltage of 1.50 V at a current density of 10 mA cm −2 in 1.0 M KOH electrolyte solution. Impressively, the full cell voltage decreases to 1.44 V through favorable self-reconstruction on both the anode and cathode during the electrocatalytic overall water splitting process. On the anode side, the FeNiMoP is transformed into FeNiOOH while Mo and P elements are dissolved into the electrolyte. Such transformation leads to a continuously increasing active surface area, and the dissolved Mo forms MoO4 2− in the electrolyte which improves the OER performance. On the cathode side, the dissolution and re-deposition of Mo oxides on the surface of the electrode greatly increase the active surface sites towards the electrolytes, and the surface absorbed Mo oxides play key roles, leading to a positive effect on HER performance. The new synthesis strategy, taking advantage of favorable structural self-reconstruction in the catalysts can be extended to other catalytic systems.