Steering surface reconstruction of hybrid metal oxides for efficient oxygen evolution reaction in water splitting and zinc-air batteries

Surface reconstruction yields real active species in electrochemical oxygen evolution reaction (OER) conditions; however, rationally regulating reconstruction in a targeted manner for constructing highly active OER electrocatalysts remains a formidable challenge. Here, an electrochemical activation strategy with selective etching was utilized to guide the reconstruction process of a hybrid cobalt-molybdenum oxide (CoMoO4/Co3O4@CC) in a favorable direction to improve the OER performance. Both in-situ Raman and multiple ex-situ characterization tools demonstrate that controlled surface reconstruction can be easily achieved through Mo etching, with the formation of a dynamically stable amorphous-crystalline heterostructure. Theoretical calculations together with experimental results reveal that the synergistic effects between amorphous CoOOH and crystalline Co3O4 are crucial in enhancing the catalytic performance. Consequently, the reconstructed CoMoO4/Co3O4@CC exhibits a low overpotential of 250 mV to achieve a current density of 10 mA cm−2 in 1 M KOH, and more importantly it can be practiced in electrolytic water splitting and rechargeable zinc-air batteries devices, achieving ultra-long stability for over 500 and 1200 h, respectively. This work provides a promising route for the construction of high-performance electrocatalysts.