Black phosphorous dots phosphatized bio-based carbon nanofibers/bimetallic organic framework as catalysts for oxygen evolution reaction

Abstract

As a multi-step and more complex half-cell reaction than the hydrogen reverse evolution reaction (HER), the oxygen evolution reaction (OER) always requires a higher overpotential than HER. In order to minimize the associated energy loss as an overpotential, these electrochemical half-reactions of water splitting should be catalyzed by suitable materials. Due to the abundant exposed surface area and extensive active edge sites, black phosphorous quantum dots (BP QDs) have shown great potential in OER. Here, BP QDs was introduced to incorporate with bio-based carbon nanofibers (CNF) and Co–Ni bimetallic organic framework (CoNiMOF), preparing a novel catalyst for oxygen evolution reaction (OER) by a facile one-pot reaction (Scheme 1). The unique structures and greater BET surface areas of CoNiMOF-BP QDs/CNF could possibly supply a larger electrocatalytic surface, expose further active sites. The obtained CoNiMOF-BP QDs/CNF possesses excellent electrocatalytic activity in alkaline electrolyte (1 M KOH) with a low overpotential of 281 mV at 10 mA cm−2 and a low Tafel slope of 111.9 mV dec−1. The CoNiMOF-BP QDs/CNF can remain stable for 25,000 s under alkaline electrolyte, showing excellent stability. The increase of electrocatalyst activity is mainly attributed to the synergistic effect of excellent conductivity and enriched active sites arising from BP QDs. This work not only provides an effective strategy for the development of bimetallic MOFs derived electrocatalysts, but also puts forward a new insight for the application of BP QDs in water splitting.