Defect-Induced Ce-Doped Bi₂WO₆ for Efficient Electrocatalytic N₂ Reduction

Electrochemical nitrogen reduction reaction (NRR) is a promising method for synthesizing ammonia (NH₃). However, due to the extremely strong N≡N bond and the competing hydrogen evolution reaction (HER), the electrochemical NRR process remains a great challenge in achieving a high NH₃ yielding rate and a high Faradaic efficiency (FE). Recently, either Bi-based or W-based catalysts have been used in N₂ fixation due to lower HER activity. To further promote N₂ activation, we develop a simple protocol to introduce and adjust the crystal defects in the host lattice of Bi₂WO₆ nanoflowers via adjusting the amount of Ce dopant (denoted as xCe-Bi₂WO₆, where x represents the designed mole percentage of Ce). At -0.20 V versus the reversible hydrogen electrode (RHE), 10%Ce-Bi₂WO₆ manifests a high NH₃ yielding rate (22.5 μg h^-1 mg^-1_cat.), a high FE (15.9%), and excellent electrochemical and structure durability. Its performance is better than most previously reported Bi-based and W-based electrocatalysts for NRR in aqueous solutions. According to density functional theory (DFT) calculations, the introduction of crystal defects into Bi₂WO₆ can strengthen the adsorption and activation of N₂, thus leading to a significant increase in NRR activity.