Se-Doping Activates FeOOH for Cost-Effective and Efficient Electrochemical Water Oxidation

Abstract

Ni or Co is commonly required in efficient electrocatalysts for oxygen evolution reaction (OER). Although Fe is much more abundant and cheaper, full-Fe or Fe-rich catalysts suffer from insufficient activity. Herein, we discover that Se-doping can drastically promote OER on FeOOH and develop a facile on-site electrochemical activation strategy for achieving such a Se-doped FeOOH electrode via an FeSe precatalyst. Theoretical analysis and systematic experiments prove that Se-doping enables FeOOH as an efficient and low-cost OER electrocatalyst. By optimizing the electrode structure, an industrial-level OER current output of 500 mA cm–2 is secured at a low overpotential of 348 mV. The application of such an Fe-rich OER electrode in a practical solar-driven water splitting system demonstrates a high and stable solar-to-hydrogen efficiency of 18.55%, making the strategy promising for exploring new cost-effective and highly active electrocatalysts for clean hydrogen production.

Highly Efficient Oxygen Evolution by a Thermocatalytic Process Cascaded Electrocatalysis Over Sulfur‐Treated Fe‐Based Metal–Organic‐Frameworks

“…[ 1,5,6 ] Recently, transition‐metal‐based electrocatalysts were also reported to achieve high OER performance. [ 7–13 ] Especially, Ni‐rich or Co‐rich materials have been used as the state‐of‐the‐art OER electrocatalysts. [ 7–10 ] It is interesting that the second most earth‐abundant metal Fe (much cheaper than Ni or Co) based electrocatalysts typically show relatively low OER activities.…”

“…[ 7–10 ] It is interesting that the second most earth‐abundant metal Fe (much cheaper than Ni or Co) based electrocatalysts typically show relatively low OER activities. [ 12,13 ] Despite extensive researches over the past years, most OER catalysts still need high overpotentials of 250–400 mV to reach the current density of interest (around 10 mA cm −2 ). [ 1–9 ] Moreover, for large‐scale industrial applications, excellent OER catalysts should also work on a high current density (>500 mA cm −2 ) at a relatively low overpotential (<300 mV), and show a long‐term stability during strong gas evolution.…”

Oxygen Reduction Reactions on Single‐ or Few‐Atom Discrete Active Sites for Heterogeneous Catalysis

“…Being one of the most potential cost‐effective non‐noble‐metal catalysts, Fe‐based catalysts are likely to play a pivotal role in the transition to a sustainable society. One of the key aspects for Fe‐based catalysts is to ensure a high conductivity by improving charge‐carrier concentrations . This can be achieved by the doping of carbon by Fe atoms to obtain optimal electronic and geometric structures, and strategies for this are summarized below.…”

“…One of the key aspects for Fe-based catalysts is to ensure a high conductivity by improving charge-carrier concentrations. [53,[102][103][104] This can be achieved by the doping of carbon by Fe atoms to obtain optimal electronic and geometric structures, and strategies for this are summarized below. Concurrently, a vital aspect for single or few-atom motifs to improve the ORR efficiency is to obtain a structural design of the catalysts that enhances the selectivity toward 4e − reduction of O 2 by suppressing the production of H 2 O 2 .…”

ZnO‐Templated Selenized and Phosphorized Cobalt‐Nickel Oxide Microcubes as Rapid Alkaline Water Oxidation Electrocatalysts

“…[5,21] Different degrees of Se introductionh ave been investigated. Li et al [22] proposed Se doping to improvet he OER performance of FeOOH. Twoc rystal phases of selenides, CoSe 2 and Co 0.85 Se, weres tudied separately as HER catalysts.…”