Approaching the activity limit of CoSe2 for oxygen evolution via Fe doping and Co vacancy

Abstract

Electronic structure engineering lies at the heart of efficient catalyst design. Most previous studies, however, utilize only one technique to modulate the electronic structure, and therefore optimal electronic states are hard to be achieved. In this work, we incorporate both Fe dopants and Co vacancies into atomically thin CoSe 2 nanobelts for /coxygen evolution catalysis, and the resulted CoSe 2-D Fe-V Co exhibits much higher catalytic activity than other defect-activated CoSe 2 and previously reported FeCo compounds. Deep characterizations and theoretical calculations identify the most active center of Co 2 site that is adjacent to the V Co-nearest surface Fe site. Fe doping and Co vacancy synergistically tune the electronic states of Co 2 to a near-optimal value, resulting in greatly decreased binding energy of OH* (ΔE OH) without changing ΔE O , and consequently lowering the catalytic overpotential. The proper combination of multiple defect structures is promising to unlock the catalytic power of different catalysts for various electrochemical reactions.

Trifunctional Single‐Atomic Ru Sites Enable Efficient Overall Water Splitting and Oxygen Reduction in Acidic Media

“…For the OER pathway, which involves proton-coupled electron transfer steps and the intermediates of *OH, *O, and *OOH. [53,54] Therefore, the OER activities are mainly evaluated by the energetics of the intermediates (*OH, *O, and *OOH) on the catalyst surfaces, which is demonstrated by the previous studies. [55] In this work, the Gibbs free energies of the OER over the Ti 3 C 2 T x and Ru-SA/Ti 3 C 2 T x were calculated and provided in Figure 7c.…”

Recent Progress of Vacancy Engineering for Electrochemical Energy Conversion Related Applications

“…As discussed above, the introduced anionic and cationic vacancies improved electrocatalytic performance efficiently, but few studies have investigated the presence of anionic and cationic vacancies in the same nanomaterials. More recently, Zhao and co‐workers [ 115 ] introduced Co or Se vacancies into Fe‐doped CoSe 2 nanobelts and then investigated the catalytic activities of the prepared material for OER. As shown in Figure 13d, CoSe 2 was mixed with diethylenetriamine (DETA) during hydrothermal process to form CoSe 2 /DETA composite.…”

“…Reproduced under the terms of the Creative Commons Attribution 4.0 International License. [ 115 ] Copyright 2020, The Authors, published by Nature Publishing Group.…”

An Efficient Turing‐Type Ag2Se‐CoSe2 Multi‐Interfacial Oxygen‐Evolving Electrocatalyst**

“…The boosted electron transfer property of Ag 2 Se-CoSe 2 prompted us to explore this new structure for negotiating the sluggish OER catalysis, considering that decent OER activities have been observed previously on CoSe 2 -based catalysts [31][32][33][34] . We compared the OER activity of our Turing- and Ir/C catalyst, respectively.…”