Amorphous Boron Oxide Coated NiCo Layered Double Hydroxide Nanoarrays for Highly Efficient Oxygen Evolution Reaction

An amorphous boron oxide layer has been deposited in situ on the NiCo-LDH (layered double hydroxide) nanosheet arrays via the simple chemical vapor deposition. The overpotential of the NiCo-LDHs@B2O3/carbon paper (NiCo-LDHs@B2O3/CP) electrode is only 213 mV at the current density of 10 mA cm–2 in 1 M KOH, which is 123 mV less than that of NiCo-LDHs/CP and slightly better than noble metal catalyst RuO2/CP (230 mV). What's more, at 50 mA cm–2 in 1.0 M KOH, the overpotential of NiCo-LDHs@B2O3/CP is still kept at a low value of 320 mV much better than that of NiCo-LDHs/CP (441 mV) and RuO2/CP (373 mV). Importantly, it showed long-term electrochemical stability. The introduction of amorphous boron oxide layers can be promoted to form a borate interface, and it can effectively enhance reactivity of active species. The boron oxide shell on the surface of LDHs can protect active species stability to enhance cycling stability. This work may inspire the development of low-cost and efficient OER electrocatalysts for energy conversion with NiCo-LDHs@B2O3/CP.