Vapor-Phase Hydrothermal Construction of Dispersed Au on Carbon Felt for Electrocatalytic Nitrate Reduction to Ammonia

Electrocatalytic nitrate ion (NO3–) reduction reaction (NO3RR) offers a sustainable and promising economic process to ammonia (NH3) synthesis, yet the biggest problem is the lack of efficient catalysts. This work designed and prepared dispersed Au nanocrystals on carbon felt (CF) (Au@CF) through a vapor-phase hydrothermal (VPH) method, which can efficiently catalyze the reduction reaction from NO3– to NH3 (NO3RR-to-NH3) under ambient conditions, achieving a maximal NH3 yield rate of 418.15 μg h–1 mgcat.–1 at −0.20 V (vs RHE) with a Faradaic efficiency of 81.06%, while negligible activity decay was found after ten consecutive cycle test. The NO3RR performance of Au@CF exceeds that of the bare CF substrate and pure bulk gold sheet. The VPH approach realized the in situ growth of catalysts on the substrate. This work emphasizes the importance of substrate-loaded dispersed metal catalysts for nitrate removal and NH3 synthesis.