A unique space confined strategy to construct defective metal oxides within porous nanofibers for electrocatalysis
Integrating defective nanoparticles (NPs) into a porous one-dimensional (1D) architecture is highly desirable for electrocatalysis due to the enhanced defective sites exposure, and accelerated mass transport features, yet great challenging. Here, we report the synthesis of defective metal oxides NPs-interconnected porous nanofibers via a unique space confined strategy. Central of this strategy is encapsulating Prussian blue analogues (PBAs) cubes into polyacrylonitrile (PAN) nanofibers. Due to the distinct pyrolysis behaviors of PBAs and PAN (i.e., expansion outwards, and contraction inwards, respectively), the PAN confers a space confined effect on the PBAs-derived metal oxides during calcination in air, resulting in the formation of various lattice defects and unsaturated metal sites on metal oxides. Consequently, with unsaturated metal sites, and advantageous architecture (i.e., 1D porous nanofibers), the resulting nanofibers with P dopants display good performance for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Notably, as bifunctional electrocatalysts, the nanofibers deliver an overall water-splitting current density of 10 mA cm-2 at a small voltage 1.52 V. This work paves new pathways of utilizing distinct pyrolysis behaviours of metal-organic compounds and polymers to construct defective nanomaterials with advanced architectures.