Electronically modulated nickel boron by CeO x doping as a highly efficient electrocatalyst towards overall water splitting.

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∥IrO 2 /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.