Electronic Structure Regulation and Surface Reconstruction of Iron Diselenide for Enhanced Oxygen Evolution Activity

Abstract

Regulating the electronic structure of active sites and monitoring the evolution of the active component is essential to improve the intrinsic activity of catalysts for electrochemical reactions. Herein, a highly efficient pre‐electrocatalyst of iron diselenide with rich Se vacancies achieved by phosphorus doping (denoted as P‐FeSe2) for oxygen evolution reaction (OER) is reported. Systematically experimental and theoretical results show that the formed Se vacancies with phosphorus doping can synergistically modulate the electronic structure of FeSe2 and facilitate OER kinetics with the resulting enhanced electrical conductivity and electrochemical surface area. Importantly, the in situ formed FeOOH species on the surface of the P‐FeSe2 nanorods (denoted as P‐FeOOH(Se)) during the OER process acts as an active component to efficiently catalyze OER and exhibits a low overpotential of 217 mV to reach 10 mA cm‐2 with good durability. Promisingly, an alkaline electrolyzer assembled with P‐FeOOH(Se) and Pt/C electrodes requires an ultra‐low cell voltage of 1.50 V at 10 mA cm‐2 for overall water splitting, which is superior to the RuO2 || Pt/C counterpart and most of the state‐of‐the‐art electrolyzers, demonstrating the high potential of the fabricated electrocatalyst by P doping strategy to explore more highly efficient selenide‐based catalysts for various reactions.

Highly Active Cobalt–Copper–Selenide Electrocatalysts for Solar-Driven Oxygen Evolution Reaction: An Electrochemical Activation Energy Aspect

“…Based on previous studies, it is known that transition metal selenides are transformed into oxyhydroxide species, which are active species of OER, due to surface reconstruction during OER. ,,, The ratio of Cu 1+ and Cu 2+ (Cu 1+ /Cu 2+ ) was changed from 1.06 (before the OER) to 0.98 (after OER). Also, the ratios of Co 3+ and Co 2+ (Co 3+ /Co 2+ ) were 0.87 (before OER) and 1.85 (after OER), suggesting the formation of active oxyhydroxide species due to surface reconstruction after OER. ,, Interestingly, noticeable variations were observed in the XPS spectrum of O 1s …”

“…Also, the ratios of Co 3+ and Co 2+ (Co 3+ /Co 2+ ) were 0.87 (before OER) and 1.85 (after OER), suggesting the formation of active oxyhydroxide species due to surface reconstruction after OER. 23,44,45 Interestingly, noticeable variations were observed in the XPS spectrum of O 1s. 46 Before the OER, only two types of oxygen species were present: hydroxyl species (O OH ) and adsorbed water (O W ).…”

Cr doping and heterostructure-accelerated NiFe LDH reaction kinetics assist the MoS2 oxygen evolution reaction

“…9 Therefore, to overcome this challenge, we should actively seek efficient OER catalysts. 10–12 Therefore, we should aggressively look for effective OER catalysts to help us overcome this difficulty.…”