Affiliation:
1. College of Chemistry and Molecular Sciences Engineering Research Center of Organosilicon Compounds and Materials Wuhan University Wuhan 430072 China
2. College of Chemistry and Chemical Engineering Dezhou University Dezhou 253023 China
3. College of Chemistry and Chemical Engineering Hubei University Wuhan 430062 China
Abstract
AbstractAccurately regulating the microenvironment around active sites is an important approach for boosting the overall water splitting performance of bifunctional electrocatalysts, which can drive both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) in the same electrolyte. Herein, pseudo‐pyridine‐substituted Ni(II)‐porphyrins (o‐NiTPyP, m‐NiTPyP, and p‐NiTPyP) with pseudo‐pyridine N‐atoms located at the ortho‐, meta‐, or para‐position are prepared and used as model catalysts for alkaline water splitting. Experimental and theoretical results reveal that the pseudo‐pyridine N‐atom positions can regulate the microenvironment around the active sites and the adsorption free energy of H‐donating substances by affecting the H‐bonding interaction and the NNiN bond angles of active sites, and thus those pseudo‐pyridine‐substituted Ni(II)‐porphyrins deliver better electrocatalytic activity than the Ni(II)‐tetraphenylporphyrin (NiTPP) without pseudo‐pyridine N‐atoms. Among them, m‐NiTPyP on carbon nanotubes delivers the lowest overpotentials of 267 and 138 mV at 10 mA cm−2 for the OER and HER, respectively. Specifically, m‐NiTPyP as bifunctional electrocatalyst in an alkaline electrolyzer requires only 1.62 V to drive efficient overall water splitting at 10 mA cm−2 while remaining durable. This work proposes a new H‐bond‐regulating approach of the microenvironment of electrocatalysts for effectively boosting the overall water splitting activity and deeply understanding its related mechanism.
Funder
National Natural Science Foundation of China
Science and Technology Planning Project of Shenzhen Municipality
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Cited by
28 articles.
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