Polypyrrole-wrapped Hofmann type metal-organic framework nanoflowers to boost oxygen evolution reaction

The exploration of efficient and stable metal-organic frameworks (MOFs) for electrocatalytic oxygen evolution reaction (OER) has received increasing attention. However, the limited electronic conductivity of MOFs hinders the electron transfer rate. Herein, we report the preparation of conducting polypyrrole (PPy)-modified MOF nanoflowers (MOF-NFs@PPy) as promising electrocatalysts for OER. The PPy layer significantly increases the electrical conductivity and modulates the ionic transmittance between MOF-NFs and the electrolyte. The interaction of PPy with the MOF-NFs modifies the electronic structure and improves the reaction efficiency at the active sites. The obtained MOF-NFs@PPy exhibits excellent electrocatalytic activity with an OER overpotential of only 218 mV@10 mA cm(-2) and small Tafel slope of 47.4 mV dec(- 1). In addition, the MOF-NFs@PPy exhibited excellent long-term stability (>24 h). This work may provide a new idea and a novel construction strategy for MOFs to improve OER performance.