Synergistic effect of oxygen species and vacancy for enhanced electrochemical CO2 conversion to formate on indium oxide
Tengfei Ma,
Zihao Jiao,
Haoran Qiu,
Feng Wang,
Ya Liu,
Liejin Guo
Affiliations
Tengfei Ma
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Zihao Jiao
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Haoran Qiu
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Feng Wang
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Ya Liu
Corresponding authors.; International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Liejin Guo
Corresponding authors.; International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Indium-based oxides are promising electrocatalysts for producing formate via CO2 reduction reaction, in which ∗OCHO is considered the key intermediate. Here, we identified that the ∗COOH pathway could be preferential to produce formate on In2O3 of In/In2O3 heterojunction due to the synergistic effect of oxygen species and vacancy. Specifically, ∗CO2 and ∗COOH were observed on In2O3 and related to formate production by in situ Raman spectroscopy. The theoretical calculations further demonstrated that the energy barrier of the ∗COOH formation on In2O3 was decreased in the presence of oxygen vacancy, similar to or lower than that of the ∗OCHO formation on the In surface. As a result, a formate selectivity of over 90% was obtained on prepared In/In2O3 heterojunction with 343 ± 7 mA cm−2 partial current density. Furthermore, when using a Si-based photovoltaic as an energy supplier, 10.11% solar–to–fuel energy efficiency was achieved.
