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 CoSe2 nanobelts for /coxygen evolution catalysis, and the resulted CoSe2-DFe–VCo exhibits much higher catalytic activity than other defect-activated CoSe2 and previously reported FeCo compounds. Deep characterizations and theoretical calculations identify the most active center of Co2 site that is adjacent to the VCo-nearest surface Fe site. Fe doping and Co vacancy synergistically tune the electronic states of Co2 to a near-optimal value, resulting in greatly decreased binding energy of OH* (ΔEOH) without changing ΔEO, 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.
Highlights
Electronic structure engineering lies at the heart of efficient catalyst design
We believe that the proper combination of two or more defect structures is essential to achieve near optimal electronic states and ideal intermediate binding energies, which holds the key for the construction of highly efficient water splitting electrocatalysts
We seek to fully excavate the catalytic potential of atomically thin CoSe2 nanobelts for oxygen evolution reaction (OER) by incorporating Fe dopants and Co/Se vacancies. Through both experiments and theoretical calculations, we find that the best catalyst is CoSe2–DFe–VCo and the most active center is the Co2 site adjacent to the VCo-nearest surface Fe site
Summary
Electronic structure engineering lies at the heart of efficient catalyst design. Most previous studies, utilize only one technique to modulate the electronic structure, and optimal electronic states are hard to be achieved. We believe that the proper combination of two or more defect structures is essential to achieve near optimal electronic states and ideal intermediate binding energies, which holds the key for the construction of highly efficient water splitting electrocatalysts. We seek to fully excavate the catalytic potential of atomically thin CoSe2 nanobelts for OER by incorporating Fe dopants and Co/Se vacancies Through both experiments and theoretical calculations, we find that the best catalyst is CoSe2–DFe–VCo and the most active center is the Co2 site adjacent to the VCo-nearest surface Fe site. Fe doping and Co vacancy work synergistically to optimize the electronic states of Co2, and the binding energy of OH* is dramatically decreased and high catalytic activity is achieved. Se-derived O vacancy has an obvious impact on the binding energy of O* at Co2 site, which results in relatively high overpotential and low catalytic activity
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