TY - JOUR
T1 - Engineering Surface Structure of Spinel Oxides via High-Valent Vanadium Doping for Remarkably Enhanced Electrocatalytic Oxygen Evolution Reaction
AU - Wei, Renjie
AU - Bu, Xiuming
AU - Gao, Wei
AU - Villaos, Rovi Angelo B.
AU - MacAm, Gennevieve
AU - Huang, Zhi Quan
AU - Lan, Changyong
AU - Chuang, Feng Chuan
AU - Qu, Yongquan
AU - Ho, Johnny C.
N1 - Funding Information:
We thank for the assistance of TEM from Prof. Fu-rong Chen and Mr. Tak Fu Hung. J.C.H. acknowledges the General Research Fund (CityU 11211317) and the Theme-Based Research Scheme (T42-103/16-N) of the Research Grants Council of Hong Kong SAR, China, the National Natural Science Foundation of China (Grant 51672229), and the Science Technology and Innovation Committee of Shenzhen Municipality (Grant JCYJ20170818095520778). F.-C.C. acknowledges support from the National Center for Theoretical Sciences and the Ministry of Science and Technology of Taiwan under Grants Number MOST-107-2628-M-110-001-MY3. He is also grateful to the National Center for High-Performance Computing for computer time and facilities.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/9/11
Y1 - 2019/9/11
N2 - Spinel oxides (AB2O4) with unique crystal structures have been widely explored as promising alternative catalysts for efficient oxygen evolution reactions; however, developing novel methods to fabricate robust, cost-effective, and high-performance spinel oxide based electrocatalysts is still a great challenge. Here, utilizing a complementary experimental and theoretical approach, pentavalent vanadium doping in the spinel oxides (i.e., Co3O4 and NiFe2O4) has been thoroughly investigated to engineer their surface structures for the enhanced electrocatalytic oxygen evolution reaction. Specifically, when the optimal concentration of vanadium (ca. 7.7 at. %) is incorporated into Co3O4, the required overpotential to reach a certain jGEOM and jECSA decreases dramatically for oxygen evolution reactions in alkaline media. Even after 30 h of chronopotentiometry, the required potential for V-doped Co3O4 just increases by 16.3 mV, being much lower than that of the undoped one. It is observed that the pentavalent vanadium doping introduces lattice distortions and defects on the surface, which in turn exposes more active sites for reactions. DFT calculations further reveal the rate-determining step changing from the step of∗-O to∗-OOH to the step of∗-OH to∗-O, while the corresponding energy barriers decrease from 1.73 to 1.57 eV accordingly after high-valent V doping. Moreover, the oxygen intermediate probing method using methanol as a probing reagent also demonstrates a stronger OH∗ adsorption on the surface after V doping. When vanadium doping is performed in the inverse spinel matrix of NiFe2O4, impressive performance enhancement in the oxygen evolution reaction is as well witnessed. All these results clearly illustrate that the V doping process can not only efficiently improve the electrochemical properties of spinel transition metal oxides but also provide new insights into the design of high-performance water oxidation electrocatalysts.
AB - Spinel oxides (AB2O4) with unique crystal structures have been widely explored as promising alternative catalysts for efficient oxygen evolution reactions; however, developing novel methods to fabricate robust, cost-effective, and high-performance spinel oxide based electrocatalysts is still a great challenge. Here, utilizing a complementary experimental and theoretical approach, pentavalent vanadium doping in the spinel oxides (i.e., Co3O4 and NiFe2O4) has been thoroughly investigated to engineer their surface structures for the enhanced electrocatalytic oxygen evolution reaction. Specifically, when the optimal concentration of vanadium (ca. 7.7 at. %) is incorporated into Co3O4, the required overpotential to reach a certain jGEOM and jECSA decreases dramatically for oxygen evolution reactions in alkaline media. Even after 30 h of chronopotentiometry, the required potential for V-doped Co3O4 just increases by 16.3 mV, being much lower than that of the undoped one. It is observed that the pentavalent vanadium doping introduces lattice distortions and defects on the surface, which in turn exposes more active sites for reactions. DFT calculations further reveal the rate-determining step changing from the step of∗-O to∗-OOH to the step of∗-OH to∗-O, while the corresponding energy barriers decrease from 1.73 to 1.57 eV accordingly after high-valent V doping. Moreover, the oxygen intermediate probing method using methanol as a probing reagent also demonstrates a stronger OH∗ adsorption on the surface after V doping. When vanadium doping is performed in the inverse spinel matrix of NiFe2O4, impressive performance enhancement in the oxygen evolution reaction is as well witnessed. All these results clearly illustrate that the V doping process can not only efficiently improve the electrochemical properties of spinel transition metal oxides but also provide new insights into the design of high-performance water oxidation electrocatalysts.
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U2 - 10.1021/acsami.9b10868
DO - 10.1021/acsami.9b10868
M3 - Article
C2 - 31414595
AN - SCOPUS:85072056376
SN - 1944-8244
VL - 11
SP - 33012
EP - 33021
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 36
ER -