Search

Metal–organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons, controllable porosities, and well‐defined catalytic centers. However, the poor chemical stability and low electron conductivity limited their activity, and single‐functional sites in these frameworks hindered them to show multifunctional roles in catalytic systems. Herein, we have constructed novel metal organic polymers (Co‐HAT‐CN and Ni‐HAT‐CN) with dual catalytic centers (metal–N4 and metal–N2) to catalyze oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). By using different metal centers, the catalytic activity and selectivity were well‐tuned. Among them, Co‐HAT‐CN catalyzed the ORR in a 4e− pathway, with a half‐wave potential of 0.8 V versus RHE, while the Ni‐HAT‐CN catalyze ORR in a 2e− pathway with H2O2 selectivity over 90%. Moreover, the Co‐HAT‐CN delivered an overpotential of 350 mV at 10 mA cm−2 with a corresponding Tafel slope of 24 mV dec−1 for OER in a 1.0 M KOH aqueous solution. The experimental results revealed that the activities toward ORR were due to the M–N4 sites in the frameworks, and both M–N4 and M–N2 sites contributed to the OER. This work gives us a new platform to construct bifunctional catalysts. [ABSTRACT FROM AUTHOR]

Abstract Metal–organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons, controllable porosities, and well‐defined catalytic centers. However, the poor chemical stability and low electron conductivity limited their activity, and single‐functional sites in these frameworks hindered them to show multifunctional roles in catalytic systems. Herein, we have constructed novel metal organic polymers (Co‐HAT‐CN and Ni‐HAT‐CN) with dual catalytic centers (metal–N4 and metal–N2) to catalyze oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). By using different metal centers, the catalytic activity and selectivity were well‐tuned. Among them, Co‐HAT‐CN catalyzed the ORR in a 4e− pathway, with a half‐wave potential of 0.8 V versus RHE, while the Ni‐HAT‐CN catalyze ORR in a 2e− pathway with H2O2 selectivity over 90%. Moreover, the Co‐HAT‐CN delivered an overpotential of 350 mV at 10 mA cm−2 with a corresponding Tafel slope of 24 mV dec−1 for OER in a 1.0 M KOH aqueous solution. The experimental results revealed that the activities toward ORR were due to the M–N4 sites in the frameworks, and both M–N4 and M–N2 sites contributed to the OER. This work gives us a new platform to construct bifunctional catalysts.

Graphical abstract Highlights • Polymer phenylethnylcopper (PPECu) nanowires were fabricated via a facile self assembled method. • P-type semiconductor of PPECu exhibited much higher photoelectric properties than g-C 3 N 4. • PPECu can activate molecular oxygen to produce superoxide radicals under visible light. • Providing a new concept for design photocatalysis based on self-assembled metal organic polymers. Abstract PPECu nanowires were synthesized and the structure was explored. It was a metal organic polymer self-assembled by copper and phenylacetylene coordination and a p-type semiconductor material with the band gap of 2.48 eV. PPECu nanowires have excellent film-forming properties and exhibit hydrophobic properties. The photocurrent of PPECu was 10 times higher than that of g-C 3 N 4 under the same conditions. The photoelectric conversion efficiency was 4.08% at 410 nm. It can activate molecular oxygen to produce superoxide radicals under visible light and the photocatalytic degradation of phenol and 2,4-DCP activity was 2.52 and 3.85 times higher than g-C 3 N 4. Therefore, PPECu has a good potential at the application in the photoelectric conversion and photocatalytic degradation of pollutants. [ABSTRACT FROM AUTHOR]