A Janus cerium-doped bismuth oxide electrocatalyst for complete water splitting

Green hydrogen production from water electrolysis typically requires a set of two catalysts for triggering both hydrogen and oxygen production. Here, we report cerium-doped α-Bi2O3 nanosheets covered with reduced graphene oxide capable of both electrocatalytic oxygen evolution reaction and hydrogen evolution reaction in the same alkaline media. This rationally designed material achieves oxygen evolution and hydrogen production current density of 10 mA cm−2 at relatively low overpotentials of 0.245 and 0.334 V, respectively, while retaining its reactivity over 24 h with minimal loss of Faradaic efficiency. A two-electrode setup is devised by immobilizing this robust and dual-active electrocatalyst on commercially available stainless steel (SS) mesh, which operates at a relatively low cell voltage (1.78 V). The electrocatalytic reactivity remains intact even after cross-polarization. Hence this Janus catalytic material may be an apt choice for developing an economical, efficient, eco-friendly alkaline water electrolyzer.