Spray-assembled nanoscale cobalt-oxide as highly efficient and durable bifunctional electrocatalyst for overall water splitting

Water splitting is an overgrowing research field and there is a huge challenge to develop easily accessible and applied methods for facile fabrication of durable electroactive thin-film catalysts. Here we demonstrate a simple cost-effective spray-coating strategy to develop ultrathin and highly crystalline CoOx nanoparticulate thin-films as a bifunctional electrocatalyst for overall water splitting. During electrocatalysis, nanoscale surface-coated CoOx (SC-CoOx NPs) exhibits high activity while initiating OER and HER just at 1.48 V-RHE and 0.22 V-RHE, respectively, and displayed current decades for OER and HER at an overpotential of 300 mV and 350 mV, respectively. Furthermore, the high electrochemically active surface area of 301 cm(2), facile electrode kinetics and low charge transfer resistance at electrode-electrolyte interphase are observed that promote efficient electron transfer and facilitate adsorption/ desorption of various intermediates during water splitting process thus making it energy efficient. DFT calclations also suggest that the electrode is very feasible for water oxidation catalysis which is ruling reaction under employed conditions. The electrocatalyst also presented superior long-term durabilities during extended period water electrolysis experiments. The present material, method and approach of growing metal-oxide nanoscale and thin-film assemblage of catalytic materials can offer an exciting and straightforward approach for producing highly applied catalytic materials. (C) 2020 Elsevier Ltd. All rights reserved.