Quantum Effects Allow the Construction of Two‐Dimensional Co3O4‐Embedded Nitrogen‐Doped Porous Carbon Nanosheet Arrays from Bimetallic MOFs as Bifunctional Oxygen Electrocatalysts

• Published in: Chemistry : a European journal 2018-09, Vol.24 (54), p.14522-14530
• Main Authors: Zhang, Hao, Xu, Jiaying, Jin, Yiwen, Tong, Yinlin, Lu, Qingyi, Gao, Feng
• Format: Article
• Language: English
• Subjects: Ammonia; Arrays; Bimetals; Carbon; Catalysis; Catalysts; Charge transport; Chemical reduction; Chemistry; Co3O4; Cobalt oxides; Crystals; EGR-1 protein; Electrical conductivity; Electrical resistivity; Electrocatalysts; Electrolytic cells; Fuel cells; Fuel technology; Nanoparticles; nanosheet arrays; Nanosheets; Nitrogen; Oxygen; oxygen evolution reaction; Oxygen evolution reactions; oxygen reduction reaction; Oxygen reduction reactions; quantum effects; Structural stability; Surface charge; Water splitting
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201802898

In terms of promising candidates for high‐performance fuel cells and water splitting electrocatalysts, two‐dimensional (2D) materials refer to a class of materials with high electrical conductivity along 2D conducting channels and possessing abundant active sites in the form of surface atoms and edge sites. Herein, we report an ammonia‐modulated method for the synthesis of nanosized bimetallic ZnCo‐ZIF, and owing to quantum effects, the nanosized ZnCo‐ZIF can be transformed into novel 2D nanosheet arrays, which can be used as a bifunctional electrocatalyst. The size of the ZnCo‐ZIF crystals can be controlled to less than 10 nm by increasing the ammonia amount. The products from the nanosized particles through calcination have a distinct structure from the microsized nanoparticles owing to quantum effects and appear to be well‐aligned 2D mono‐crystalline Co3O4‐embedded nitrogen‐doped porous carbon nanosheet arrays (2D‐MCo3O4‐NCNAs). These novel 2D nanosheet arrays lead to large active surface areas, enhanced mass/charge transport capability, numerous active sites, and strong structure stability. When used as bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), the 2D‐MCo3O4‐NCNAs exhibit superior ORR activity as well as efficient OER activity in alkaline electrolyte, in comparison to the state‐of‐the‐art precious metal catalysts. On the flat: Nanosized ZnCo‐ZIF made by an ammonia‐modulated method can be transformed into novel 2D nanosheet arrays through quantum effects. These novel 2D nanosheet arrays led to large active surface areas, enhanced mass/charge transport capability, numerous active sites, and strong structure stability. When used as bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), the arrays exhibit superior ORR activity as well as efficient OER activity in alkaline electrolyte, in comparison to the state‐of‐the‐art precious metal catalysts.