Tailoring acidic oxygen reduction selectivity on single-atom catalysts via modification of first and second coordination spheres
Date
2021
Authors
Tang, C.
Chen, L.
Li, H.
Li, L.
Jiao, Y.
Zheng, Y.
Xu, H.
Davey, K.
Qiao, S.
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Journal article
Citation
Journal of the American Chemical Society, 2021; 43(20):4819-4827
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Cheng Tang, Ling Chen, Haijing Li, Laiquan Li, Yan Jiao, Yao Zheng, Haolan Xu, Kenneth Davey, and Shi-Zhang Qiao
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Abstract
Product selectivity in multielectron electrocatalytic reactions is crucial to energy conversion efficiency and chemical production. However, a present practical drawback is the limited understanding of actual catalytic active sites. Here, using as a prototype single-atom catalysts (SACs) in acidic oxygen reduction reaction (ORR), we report the structure–property relationship of catalysts and show for the first time that molecular-level local structure, including first and second coordination spheres (CSs), rather than individual active atoms, synergistically determines the electrocatalytic response. ORR selectivity on Co-SACs can be tailored from a four-electron to a two-electron pathway by modifying first (N or/and O coordination) and second (C–O–C groups) CSs. Using combined theoretical predictions and experiments, including X-ray absorption fine structure analyses and in situ infrared spectroscopy, we confirm that the unique selectivity change originates from the structure-dependent shift of active sites from the center Co atom to the O-adjacent C atom. We show this optimizes the electronic structure and *OOH adsorption behavior on active sites to give the present “best” activity and selectivity of >95% for acidic H₂O₂ electrosynthesis.
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© 2021 American Chemical Society