Contents lists available at ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej Tuning the electronic structure of AuNi homogeneous solid-solution alloy with positively charged Ni center for highly selective electrochemical CO 2 reduction Jican Hao a,1 , Han Zhu a, ⁎ ,1 , Youzhi Li b , Pengxin Liu c , Shuanglong Lu a , Fang Duan a , Weifu Dong a , Yingying Lu b , Tianxi Liu a , Mingliang Du a, ⁎ a Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China b College of Chemical And Biological Engineering, Zhejiang University, Hangzhou 310027, China c Department of Chemistry and Applied Bioscience, ETH Zürich Vladimir Prelog Weg 2, 8093 Zürich, Switzerland HIGHLIGHTS • 1. AuNi alloy with positive charged Ni center were synthesized on electro- spun CNFs. • 2. AuNi with enhanced electronic in- teraction caused by the electron withdrawal from Au. • 3. AuNi alloy exhibits a high CO se- lectivity with CO Faradaic efficiency of 92%. • 4. AuNi alloy make the d-band center more positive and reduce the free en- ergy barrier. • 5. In situ technologies reveal the phase evolution and active sites for CO 2 re- duction. GRAPHICAL ABSTRACT A concept of atom-polymer hybridization to design homogeneous AuNi solid-solution alloy nanoparticles with positively charged Ni center supported on electrospun carbon nanofibers as highly efficient CO 2 RR catalysts have been demonstrated. ARTICLE INFO Keywords: Carbon dioxide reduction Homogeneous solid-solution alloy Electronic structure Electrospinning Materials chemistry ABSTRACT Designing bimetallic electrocatalysts with homogenous element distribution and tunable electronic structure is attractive strategy to enhance the CO selectivity in electrochemical carbon dioxide reduction reaction (CO 2 RR). Herein, we report a concept of atom-polymer hybridization to synthesize AuNi homogeneous solid-solution alloy nanoparticles (NPs) with positively charged Ni center supported on electrospun carbon nanofibers (CNFs). The nanofibers host can strong restrict the separated growth of Au and Ni nanoclusters during the directly graphi- tization process, leading to the formation of homogeneous AuNi alloy. In-situ characterizations reveal the for- mation process and phase evolution of the AuNi alloy during the carbonization. The positively charged Ni when alloying with Au lead to the enhanced local electronic structure on AuNi homogeneous solid-solution alloy due to the electron-withdrawal effect of nearby Au atoms. The AuNi homogeneous solid-solution alloy exhibits a high CO selectivity with an optimal CO Faradaic efficiency (FE CO ) of 92% at −0.98 V (vs. RHE). Theoretical cal- culations indicate that the incorporation of Ni into Au can make the d-band center more positive and reduce the https://doi.org/10.1016/j.cej.2020.126523 Received 5 May 2020; Received in revised form 30 July 2020; Accepted 31 July 2020 ⁎ Corresponding authors. E-mail addresses: zhysw@jiangnan.edu.cn (H. Zhu), du@jiangnan.edu.cn (M. Du). 1 J. Hao and H. Zhu contributed equally to this work. Chemical Engineering Journal 404 (2021) 126523 Available online 03 August 2020 1385-8947/ © 2020 Elsevier B.V. All rights reserved. T