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Nano Research

Article Title

PdAg bimetallic electrocatalyst for highly selective reduction of CO2 with low COOH* formation energy and facile CO desorption

Authors

Rui Lin, Department of Chemistry, Tsinghua University, Beijing 100084, China
Xuelu Ma, School of Chemical & Environment Engineering, China University of Mining & Technology, Beijing 100083, China
Weng-Chon Cheong, Department of Chemistry, Tsinghua University, Beijing 100084, China
Chao Zhang, Department of Chemistry, Tsinghua University, Beijing 100084, China
Wei Zhu, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
Jiajing Pei, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
Kaiyue Zhang, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China
Bin Wang, Sinopec Beijing Research Institute of Chemical Industry, Beijing 100013, China
Shiyou Liang, School of Materials Science and Engineering, National Center for Electron Microscopy in Beijing, Tsinghua University, Beijing 100084, China
Yuxi Liu, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China
Zhongbin Zhuang, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
Rong Yu, School of Materials Science and Engineering, National Center for Electron Microscopy in Beijing, Tsinghua University, Beijing 100084, China
Hai Xiao, Department of Chemistry, Tsinghua University, Beijing 100084, China
Jun Li, Department of Chemistry, Tsinghua University, Beijing 100084, China
Dingsheng Wang, Department of Chemistry, Tsinghua University, Beijing 100084, China
Qing Peng, Department of Chemistry, Tsinghua University, Beijing 100084, China
Chen Chen, Department of Chemistry, Tsinghua University, Beijing 100084, China
Yadong Li, Department of Chemistry, Tsinghua University, Beijing 100084, China

Keywords

CO2 reduction, bimetallic, low overpotential, CO desorption

Abstract

For electrocatalytic reduction of CO2 to CO, the stabilization of intermediate COOH* and the desorption of CO* are two key steps. Pd can easily stabilize COOH*, whereas the strong CO* binding to Pd surface results in severe poisoning, thus lowering catalytic activity and stability for CO2 reduction. On Ag surface, CO* desorbs readily, while COOH* requires a relatively high formation energy, leading to a high overpotential. In light of the above issues, we successfully designed the PdAg bimetallic catalyst to circumvent the drawbacks of sole Pd and Ag. The PdAg catalyst with Ag-terminated surface not only shows a much lower overpotential (−0.55 V with CO current density of 1 mA/cm2) than Ag (−0.76 V), but also delivers a CO/H2 ratio 18 times as high as that for Pd at the potential of −0.75 V vs. RHE. The issue of CO poisoning is significantly alleviated on Ag-terminated PdAg surface, with the stability well retained after 4 h electrolysis at −0.75 V vs. RHE. Density functional theory (DFT) calculations reveal that the Ag-terminated PdAg surface features a lowered formation energy for COOH* and weakened adsorption for CO*, which both contribute to the enhanced performance for CO2 reduction.

Graphical Abstract

Publisher

Tsinghua University Press

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