Quantum dot-doped CeOx–NiB with modulated electron density as a highly efficient bifunctional electrocatalyst for water splitting

Abstract

Development of economical, efficient and durable non-noble metal electrocatalysts for the hydrogen/oxygen evolution reaction (HER/OER) holds great promise, but still faces great challenges. Herein, a strategy of doping metal borides with rare earth metal oxides and introducing silicon carbide (SiC) quantum dots has been explored to develop efficient bifunctional electrocatalysts. A novel electrocatalyst consists of SiC quantum dot-decorated CeO_x–NiB supported on nickel foam via a one-step mild electroless plating reaction (denoted as CeO_x–NiB/SiC@NF). Notably, the modulated electron density of the CeO_x–NiB/SiC@NF electrode significantly boosts the electrochemically active surface area and electron transfer, and optimizes the hydrogen/water absorption free energy, which delivers current densities of 50 mA cm⁻² and 10 mA cm⁻² at overpotentials of only 131 mV and 234 mV for the HER and the OER, respectively. The target electrode requires only 1.43 V to provide 10 mA cm⁻² for overall water splitting in 1.0 M KOH. Moreover, the electrode also exhibits good stability and durability at the industrial-grade current density (0.5–1 A cm⁻²). This work provides a new idea for the development of efficient and durable non-precious metal catalysts.