The development of high-performance multifunctional electrocatalysts operating in the same electrolyte is key to reduce the material and process costs of renewable energy conversion and storage devices. Herein, the fabrication of freestanding integral electrodes by combining multivariate electrospinning with surface metal organic framework functionalization to arrest pyrolytic emissions from fiber interior is reported, resulting in the expression of rich active sites with controlled composition, for example, the tunable Co-P coordination. The as-fabricated electrode of CoP@CF-900, when used as both the cathode and anode for overall water splitting, is able to deliver 200 mA cm-2 at a cell voltage of 1.89 V, significantly outshining the Pt/C‖RuO2 couple; when used as the air cathode for a zinc-air battery, is able to operate more than 150 h at 10 mA cm-2 with a nearly constant round-trip energy efficiency of ≈60%, also outperforming the Pt/C+RuO2 benchmark. The activity and kinetics origin of the superb multi-functionality is further elucidated through extensive electroanalytical, post-mortem, and operando characterizations, which underscore the construction of robust integral electrodes through synergistic structure and composition engineering.
Keywords: freestanding integral electrodes; overall water splitting; transition metal phosphides; trifunctional electrocatalysis; zinc-air batteries.
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