Zinc‐Mediated Template Synthesis of Fe‐N‐C Electrocatalysts with Densely Accessible Fe‐Nx Active Sites for Efficient Oxygen Reduction. Issue 8 (16th January 2020)

• Record Type: Journal Article
• Authors: Chen, Guangbo; Liu, Pan; Liao, Zhongquan; Sun, Fanfei; He, Yanghua; Zhong, Haixia; Zhang, Tao; Zschech, Ehrenfried; Chen, Mingwei; Wu, Gang; Zhang, Jian; Feng, Xinliang
• Is Part Of: Advanced materials. Volume 32:Issue 8(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-16
• Subjects: accessible active sites -- Fe‐N‐C catalysts -- oxygen reduction reaction -- zinc‐mediated synthesis -- Zn–air batteries; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201907399
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Owing to their earth abundance, high atom utilization, and excellent activity, single iron atoms dispersed on nitrogen‐doped carbons (Fe‐N‐C) have emerged as appealing alternatives to noble‐metal platinum (Pt) for catalyzing the oxygen reduction reaction (ORR). However, the ORR activity of current Fe‐N‐C is seriously limited by the low density and inferior exposure of active Fe‐N x species. Here, a novel zinc‐mediated template synthesis strategy is demonstrated for constructing densely exposed Fe‐N x moieties on hierarchically porous carbon (SA‐Fe‐NHPC). During the thermal treatment of 2, 6‐diaminopyridine/ZnFe/SiO2 complex, the zinc prevents the formation of iron carbide nanoparticles and the SiO2 template promotes the generation of hierarchically pores for substantially improving the accessibility of Fe‐N x moieties after subsequent leaching. As a result, the SA‐Fe‐NHPC electrocatalysts exhibit an unprecedentedly high ORR activity with a half‐wave potential ( E 1/2 ) of 0.93 V in a 0.1 m KOH aqueous solution, which outperforms those for Pt/C catalyst and state‐of‐the‐art noble metal‐free electrocatalysts. As the air electrode in zinc–air batteries, the SA‐Fe‐NHPC demonstrates a large peak power density of 266.4 mW cm −2 and superior long‐term stability. Therefore, the developed zinc‐mediated template synthesis strategy for boosting the density and accessibility of Fe‐N x species paves a new avenue toward high‐performance ORR electrocatalysts. Abstract : A novel zinc‐mediated template synthesis strategy is developed to prepare Fe‐N‐C electrocatalysts with densely accessible Fe‐N x active sites. As a result, the prepared material exhibits an excellent electrocatalytic activity for the oxygen reduction reaction (ORR), which is superior to those of Pt/C and state‐of‐the‐art PGM‐free electrocatalysts. This method paves a new avenue toward the rational design of high‐performance ORR electrocatalysts.