Organic–Inorganic Cobalt-Phosphonate-Derived\nHollow Cobalt Phosphate Spherical Hybrids for Highly Efficient Oxygen\nEvolution

Abstract

The construction\nof intimately coupled carbon/metal hybrids with\na hierarchical structure is one of the efficient approaches to boost\ntheir corresponding electrocatalytic performances due to the significantly\nsynergistic effect between two components and the fascinating structural\nadvantages. Herein, hollow spherical hybrids composed of cobalt phosphate\nand sufficient heteroatoms-doped carbon (CoPi-HSNPC) are obtained\nby the direct pyrolysis of organic–inorganic cobalt phosphonate\n(Co-BHMTPMPA). The homogeneously distributed organophosphonic ligands\nin the cobalt phosphonate hybrid framework evidently ensure the intimately\ncoupled interaction between the <i>in situ</i> formed heteroatoms-doped\nconductive carbon substrates and cobalt phosphate nanoparticles. The\nas-prepared CoPi-HSNPC exhibits extraordinary electrocatalytic activity\nfor the oxygen evolution reaction (OER) with a small overpotential\n(320 mV at 10 mA cm^–2) and robust stability in alkaline\nconditions. In addition, Ni-based and Mn-based hollow spherical hybrids\nare also synthesized by this facile metal-phosphonate-derivation method,\nexhibiting a decent performance toward the OER. This work highlights\nthe universal property of organic–inorganic metal phosphonates\nfor the fabrication of metal phosphate hybrids with hierarchical nanostructures,\nwhich have significant potential for enhancing energy conversion applications.