Electronically modulated nickel boron by CeOx doping as a highly efficient electrocatalyst towards overall water splitting

Abstract

Exploiting economic, efficient and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is promising, but still faces enormous challenges. Herein, the strategy of doping a metal boride with a rare earth metal oxide has been explored to develop a highly efficient bifunctional electrocatalyst. The novel electrocatalyst CeO_x-NiB consists of CeO_x-doped NiB supported on nickel foam, and was fabricated by a one-step mild electroless plating reaction. Remarkably, the CeO_x-NiB@NF electrode delivers a current density of 10 mA cm⁻² at overpotentials of only 19 mV and 274 mV for the HER and OER, respectively. Two-electrode electrolyzers with the CeO_x-NiB@NF electrode require only 1.424 V to deliver 10 mA cm⁻² for overall water splitting in 1.0 M KOH, outperforming the Pt–C/NF∥IrO₂/NF electrolyzer. Meanwhile, the electrode also has good stability (can work for 100 hours at 10 mA cm⁻²) and industrial-grade current density. This work provides a new idea for the development of efficient and durable non-precious metal catalysts.