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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.


Intrinsic ORR/OER activity of SC CoO NCs in comparison with the activity of PC CoO NCs.(a,b) Jk and Jk,specific for ORR at 0.6 VRHE, respectively. (c,d) J and Jspecific for OER at 1.65 VRHE, respectively.
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f5: Intrinsic ORR/OER activity of SC CoO NCs in comparison with the activity of PC CoO NCs.(a,b) Jk and Jk,specific for ORR at 0.6 VRHE, respectively. (c,d) J and Jspecific for OER at 1.65 VRHE, respectively.

Mentions: To decouple the enhanced activity of SC CoO NRs from the contribution of advanced 1D nanoarray architecture, the intrinsic ORR/OER activity of SC CoO NCs with sizes of ∼50 nm (Supplementary Method) was evaluated in comparison to that of PC CoO NCs (Supplementary Figs 16–18 and Supplementary Note 4) and other well-developed particulate cobalt oxide catalysts (Supplementary Table 6). The ORR kinetic current and OER current are normalized by the electrochemically active surface area of catalyst to obtain the specific ORR kinetic current density (Jk,specific) and the specific OER current density (Jspecific), respectively (see definition in Supplementary Table 3). As shown in Fig. 5a,b, for ORR, Jk and Jk,specific of SC CoO NCs at 0.6 VRHE are about 4.2 and 7.2 times greater than those of PC CoO NCs, respectively. As regards OER, J and Jspecific of SC CoO NCs at 1.65 VRHE are about 1.5 and 2.6 times larger than those of PC CoO NCs, respectively (Fig. 5c,d). These collective results clearly demonstrate that the intrinsic ORR/OER activity of CoO is strongly dependent on the surface structure.


Engineering surface atomic structure of single-crystal cobalt (II) oxide nanorods for superior electrocatalysis
Intrinsic ORR/OER activity of SC CoO NCs in comparison with the activity of PC CoO NCs.(a,b) Jk and Jk,specific for ORR at 0.6 VRHE, respectively. (c,d) J and Jspecific for OER at 1.65 VRHE, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Intrinsic ORR/OER activity of SC CoO NCs in comparison with the activity of PC CoO NCs.(a,b) Jk and Jk,specific for ORR at 0.6 VRHE, respectively. (c,d) J and Jspecific for OER at 1.65 VRHE, respectively.
Mentions: To decouple the enhanced activity of SC CoO NRs from the contribution of advanced 1D nanoarray architecture, the intrinsic ORR/OER activity of SC CoO NCs with sizes of ∼50 nm (Supplementary Method) was evaluated in comparison to that of PC CoO NCs (Supplementary Figs 16–18 and Supplementary Note 4) and other well-developed particulate cobalt oxide catalysts (Supplementary Table 6). The ORR kinetic current and OER current are normalized by the electrochemically active surface area of catalyst to obtain the specific ORR kinetic current density (Jk,specific) and the specific OER current density (Jspecific), respectively (see definition in Supplementary Table 3). As shown in Fig. 5a,b, for ORR, Jk and Jk,specific of SC CoO NCs at 0.6 VRHE are about 4.2 and 7.2 times greater than those of PC CoO NCs, respectively. As regards OER, J and Jspecific of SC CoO NCs at 1.65 VRHE are about 1.5 and 2.6 times larger than those of PC CoO NCs, respectively (Fig. 5c,d). These collective results clearly demonstrate that the intrinsic ORR/OER activity of CoO is strongly dependent on the surface structure.

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.