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Engineering surface atomic structure of single-crystal cobalt (II) oxide nanorods for superior electrocatalysis

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ABSTRACT

Engineering the surface structure at the atomic level can be used to precisely and effectively manipulate the reactivity and durability of catalysts. Here we report tuning of the atomic structure of one-dimensional single-crystal cobalt (II) oxide (CoO) nanorods by creating oxygen vacancies on pyramidal nanofacets. These CoO nanorods exhibit superior catalytic activity and durability towards oxygen reduction/evolution reactions. The combined experimental studies, microscopic and spectroscopic characterization, and density functional theory calculations reveal that the origins of the electrochemical activity of single-crystal CoO nanorods are in the oxygen vacancies that can be readily created on the oxygen-terminated {111} nanofacets, which favourably affect the electronic structure of CoO, assuring a rapid charge transfer and optimal adsorption energies for intermediates of oxygen reduction/evolution reactions. These results show that the surface atomic structure engineering is important for the fabrication of efficient and durable electrocatalysts.

No MeSH data available.


Schematic illustration of engineering the surface of SC CoO NRs.(a) SC CoO NRs fabricated directly on carbon fibre substrate. (b) Numerous nanopores present on the surface and across SC NRs. (c) The surface of SC CoO NRs covered with textured nanopyramids. (d) The dominant exposed facets of nanopyramids are electrochemically active vacancy-rich O-terminated {111} facets.
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f1: Schematic illustration of engineering the surface of SC CoO NRs.(a) SC CoO NRs fabricated directly on carbon fibre substrate. (b) Numerous nanopores present on the surface and across SC NRs. (c) The surface of SC CoO NRs covered with textured nanopyramids. (d) The dominant exposed facets of nanopyramids are electrochemically active vacancy-rich O-terminated {111} facets.

Mentions: Very recently, one-dimensional (1D) nanoarrays directly grown on the current collectors have attracted a lot of attention in electrocatalysis163839404142 because their 1D morphology assures adequate diffusion of reactants and rapid charge transport. Although a great progress has been achieved in electrocatalysis, much less has been done towards engineering the surface atomic structure of the aforementioned nanoarrays to explore their full potential. Herein, we report the surface structure engineering of single-crystal (SC) CoO nanorods (NRs) through creating desired facets and defects (Fig. 1). Our experiments, microscopic and spectroscopic characterization and the density functional theory (DFT) computation studies demonstrate that the O-vacancies present on the pyramidal nanofacets of CoO NRs can be effectively used to tailor the electronic structure of NRs, which results in rapid charge transfer and favourable energetics for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as evidenced by excellent activity and durability of CoO NRs towards both reactions. Significantly, their ORR activity approaches that of platinum (Pt) catalysts and their OER activity exceeds that of ruthenium dioxide (RuO2) catalysts; their overall activity is comparable to that of the best bifunctional ORR/OER catalysts.


Engineering surface atomic structure of single-crystal cobalt (II) oxide nanorods for superior electrocatalysis
Schematic illustration of engineering the surface of SC CoO NRs.(a) SC CoO NRs fabricated directly on carbon fibre substrate. (b) Numerous nanopores present on the surface and across SC NRs. (c) The surface of SC CoO NRs covered with textured nanopyramids. (d) The dominant exposed facets of nanopyramids are electrochemically active vacancy-rich O-terminated {111} facets.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5035995&req=5

f1: Schematic illustration of engineering the surface of SC CoO NRs.(a) SC CoO NRs fabricated directly on carbon fibre substrate. (b) Numerous nanopores present on the surface and across SC NRs. (c) The surface of SC CoO NRs covered with textured nanopyramids. (d) The dominant exposed facets of nanopyramids are electrochemically active vacancy-rich O-terminated {111} facets.
Mentions: Very recently, one-dimensional (1D) nanoarrays directly grown on the current collectors have attracted a lot of attention in electrocatalysis163839404142 because their 1D morphology assures adequate diffusion of reactants and rapid charge transport. Although a great progress has been achieved in electrocatalysis, much less has been done towards engineering the surface atomic structure of the aforementioned nanoarrays to explore their full potential. Herein, we report the surface structure engineering of single-crystal (SC) CoO nanorods (NRs) through creating desired facets and defects (Fig. 1). Our experiments, microscopic and spectroscopic characterization and the density functional theory (DFT) computation studies demonstrate that the O-vacancies present on the pyramidal nanofacets of CoO NRs can be effectively used to tailor the electronic structure of NRs, which results in rapid charge transfer and favourable energetics for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as evidenced by excellent activity and durability of CoO NRs towards both reactions. Significantly, their ORR activity approaches that of platinum (Pt) catalysts and their OER activity exceeds that of ruthenium dioxide (RuO2) catalysts; their overall activity is comparable to that of the best bifunctional ORR/OER catalysts.

View Article: PubMed Central - PubMed

ABSTRACT

Engineering the surface structure at the atomic level can be used to precisely and effectively manipulate the reactivity and durability of catalysts. Here we report tuning of the atomic structure of one-dimensional single-crystal cobalt (II) oxide (CoO) nanorods by creating oxygen vacancies on pyramidal nanofacets. These CoO nanorods exhibit superior catalytic activity and durability towards oxygen reduction/evolution reactions. The combined experimental studies, microscopic and spectroscopic characterization, and density functional theory calculations reveal that the origins of the electrochemical activity of single-crystal CoO nanorods are in the oxygen vacancies that can be readily created on the oxygen-terminated {111} nanofacets, which favourably affect the electronic structure of CoO, assuring a rapid charge transfer and optimal adsorption energies for intermediates of oxygen reduction/evolution reactions. These results show that the surface atomic structure engineering is important for the fabrication of efficient and durable electrocatalysts.

No MeSH data available.