Bimetallic Zeolitic Imidazolite Framework Derived Carbon Nanotubes Embedded with Co Nanoparticles for Efficient Bifunctional Oxygen Electrocatalyst

Abstract

Bifunctional oxygen catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with high activities and low‐cost are of prime importance and challenging in the development of fuel cells and rechargeable metal–air batteries. This study reports a porous carbon nanomaterial loaded with cobalt nanoparticles (Co@NC‐x/y) derived from pyrolysis of a Co/Zn bimetallic zeolitic imidazolite framework, which exhibits incredibly high activity as bifunctional oxygen catalysts. For instance, the optimal catalyst of Co@NC‐3/1 has the interconnected framework structure between porous carbon and embedded carbon nanotubes, which shows the superb ORR activity with onset potential of ≈1.15 V and half‐wave potential of ≈0.93 V. Moreover, it presents high OER activity that can be further enhanced to over commercial RuO2 by P‐doped with overpotentials of 1.57 V versus reversible hydrogen electrode at 10 mA cm−2 and long‐term stability for 2000 circles and a Tafel slope of 85 mV dec−1. Significantly, the nanomaterial demonstrates better catalytic performance and durability than Pt/C for ORR and commercial RuO2 and IrO2 for OER. These findings suggest the importance of a synergistic effect of graphitic carbon, nanotubes, exposed Co–Nx active sites, and interconnected framework structure of various carbons for bifunctional oxygen electrocatalysts.

Stereoselectively Assembled Metal–Organic Framework (MOF) Host for Catalytic Synthesis of Carbon Hybrids for Alkaline‐Metal‐Ion Batteries

“…[15] Thehigh-level Nd oping can be attributed to the melamine decomposition and subsequent chemical deposition. Last, the high-resolution Co 2p XPS spectrum in Figure 3d exhibited characteristic peaks of the metallic Co at 777.8 eV, [17] as well as the Co II oxidation states located at 780.1 eV (Co 2p 3/2 peak) and 795.2 eV (Co 2p 1/2 peak). Besides,asmall peak (ca.…”

2D Metal–Organic Framework Derived CuCo Alloy Nanoparticles Encapsulated by Nitrogen‐Doped Carbonaceous Nanoleaves for Efficient Bifunctional Oxygen Electrocatalyst and Zinc–Air Batteries

“…When zooming in on an individual metal nanoparticle, it wasf ound that the Cu and Co elements were welld istributed, demonstrating the formation of CuCo alloy NPs. [79][80][81][82] The intensity ratio between the Da nd Gb ands (I D /I G )o fC uCo@NC was calculated to be 1.05, which was larger than that of Co@NC catalyst (0.71), indicating the formation of more defect carbons in CuCo@NC. [74] To furtheri nvestigate the differenceb etween ZIF-L-Co and ZIF-67 used in this system, thermogravimetric analyses (TGA) of Cu(OH) 2 @ZIF-L-Co andC u(OH) 2 @ZIF-67i nN 2 were performed ( Figure 2i).…”

Nitrogen/Cobalt Co‐doped Mesoporous Carbon Microspheres Derived from Amorphous Metal‐Organic Frameworks as a Catalyst for the Oxygen Reduction Reaction in Both Alkaline and Acidic Electrolytes

“…[40,44] Supporting evidence came from XRD analysis of Co/NÀ C-800 catalyst, which showed relatively strong and narrow peaks at 2θ = 25.5°and 43.0°in its XRD pattern ( Figure S6) that belonged to (002) and (110) planes, respectively, of the graphitic-structure carbon. [51,55] Additionally, XRD peaks for Co species were rather weak, suggesting that almost all the metallic Co particles and Co oxides have been leached out during the acid-washing process, leaving behind the ORR active CoÀ N x species that can be confirmed by the XPS analysis as mentioned below.…”