Large‐area Free‐standing Metalloporphyrin‐based Covalent Organic Framework Films by Liquid‐air Interfacial Polymerization for Oxygen Electrocatalysis

Abstract

Synthesizing large‐area free‐standing covalent organic framework (COF) films is of vital importance for their applications but is still a big challenge. Herein, we reported the synthesis of large metalloporphyrin‐based COF films and their applications for oxygen electrocatalysis. The reaction of meso‐benzohydrazide‐substituted metal porphyrins with tris‐aldehyde linkers afforded free‐standing COF films at the liquid‐air interface. These films can be scaled up to 3000 cm2 area and display great mechanical stability and structural integrity. Importantly, the Co‐porphyrin‐based films are efficient for electrocatalytic O2 reduction and evolution reactions. A flexible, all‐solid‐state Zn‐air battery was assembled using the films and showed high performance with a charge–discharge voltage gap of 0.88 V at 1 mA cm−2 and high stability under bent conditions (0° to 180°). This work thus presents a strategy to synthesize functionalized COF films with high quality for uses in flexible electronics.

An ultrathin defect-rich nickel–cobalt oxide nanosheet array for enhanced bifunctional oxygen electrocatalysis

“…Notably, very recent progress has shown that metalorganic molecule-based framework catalysts are highly active in bifunctional electrocatalytic oxygen reduction and evolution reactions. [20][21][22] In the present study, a nitrogen-doped NiCoO x nanosheet array catalyst with an ultrathin thickness of 1-3 nm has been developed. The prepared electrocatalyst has a large exposed surface area, an abundance of exposed edge sites, and a firm electrical connection with a conductive substrate.…”

“…Notably, very recent progress has shown that metal–organic molecule-based framework catalysts are highly active in bifunctional electrocatalytic oxygen reduction and evolution reactions. 20–22…”

F and rare V4+doped cobalt hydroxide hybrid nanostructures: excellent OER activity with ultralow overpotential

“…22 Co-porphyrin and Co-corrole based molecular catalysts that combine metal redox property with π-conjugation of ligands showed strong OER activity. [23][24][25][26][27] Cobalt hydroxides (Co(OH) 2 ) with their abundance and environmental friendliness provided an opportunity to fabricate cost-effective OER catalysts. [28][29][30][31][32] However, the fully occupied t 2g orbitals of the MO 6 centre in Co(OH) 2 resulted in a low electron transfer conductivity and contributed to reduced OER activity.…”

A highly durable zinc-air battery from a directly integrated FexNC@NiFe(OH)xbifunctional catalyst

“…Therefore, extensive efforts have been devoted to synthesizing noble metal-free electrodes for highly efficient oxygen electrocatalysis. 17–25 Cost-effective bifunctional catalytic electrocatalysts that can accelerate both the ORR and OER have sprung up for high-performance ZABs. 26–31…”

“…Therefore, extensive efforts have been devoted to synthesizing noble metal-free electrodes for highly efficient oxygen electrocatalysis. [17][18][19][20][21][22][23][24][25] Cost-effective bifunctional catalytic electrocatalysts that can accelerate both the ORR and OER have sprung up for high-performance ZABs. [26][27][28][29][30][31] Transition metal (TM) compounds embedded in nitrogen (N)-doped carbon electrocatalysts have been screened for efficient oxygen reduction.…”