Modulating the electronic structure of zinc single atom catalyst by P/N coordination and Co2P supports for efficient oxygen reduction in Zn-Air battery

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 440; p. 135928
• Main Authors: Najam, Tayyaba, Shoaib Ahmad Shah, Syed, Sufyan Javed, Muhammad, Chen, Po-Tuan, Chuang, Chenghao, Saad, Ali, Song, Zhaoqi, Liu, Wei, Cai, Xingke
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2022
• Subjects: Dual coordination; Oxygen reduction reaction; Single metal atom; Synergistic effect; Zinc-air battery; Synergistic effect; Dual coordination; Single metal atom; Oxygen reduction reaction; Zinc-air battery
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.135928

[Display omitted] •A new precursor structure of PDAP spherical inside dodecahedron MOFs is fabricated.•Zn single atoms are coordinated with N/P atoms to form ZnN3P catalytic sites.•Co2P nanoparticles supports also promote the catalytic performance of Zn single atoms.•ZnCo-PNC show a E1/2 of 0.91 V for ORR in basic solution, better than Pt/C (0.87 V).•ZnCo-PNC based Zn-air battery device show better performance than IrO2@Pt/C couple. Single-atom catalysts have emerged as effective active species for electrocatalysis because of their appropriate structural and electronic properties. However, the weight percentage of single metal atoms are generally below 5 wt% in the catalysts, limiting the population of catalytic sites and their performance. In this work, we synthesized Zn single atoms with a configuration of ZnN3P in the carbon framework. With the Co2P particles as supports (ZnCo-PNC), the generic Zn single atom catalysts with a content of only 2 wt% showed a half-wave potential of 0.91 V for oxygen reduction reaction in alkaline medium. This value is higher than that for pure P doped Zn and Co based catalysts (Zn-PNC of 0.69 V, Co-PNC of 0.82 V), and even better than commercial Pt/C (0.87 V). DFT results demonstrated that the synergistic promotion of Co2P supports and N/P coordination could reduce the energy barrier to proceed ORR on Zn single atoms from 1.85 to 0.79 eV. By using it as the cathode catalyst for zinc-air battery application, it shows respectable performance in terms of maximum peak power (237.3 mW cm−2) and energy densities (847 W h kg−1). The current strategy may open new horizons to design high performance single atom catalysts by using suitable supports and coordination environment to tune their activity.