Direct ammonia (NH3) synthesis from nitrogen (N2) and water (H2O) is a promising route for achieving energy-efficient NH3 production by circumventing the energy-intensive H2 production process, yet it is limited by unfavorable reaction thermodynamics. Herein, we report a direct ammonia synthesis process from N2 and H2O with CO as the oxygen acceptor to remove oxygen from H2O over a Au/α-MoC1-x catalyst, thereby bypassing the thermodynamic limitation of N2 activation with H2O under mild conditions. This process achieves NH3 synthesis at temperatures as low as 100 °C, yielding 1396 μmolNH3 gcat-1 h-1 of NH3 at 320 °C. We disclose that the Au/α-MoC1-x boundary offers Auδ+ species for CO adsorption to vacate oxygen-covered Mo sites for N2 adsorption and H2O dissociation to OH* species, enabling stepwise N2 hydrogenation to NH3. This process enables direct ammonia synthesis from nitrogen and water through the synergistic cooperation of the oxygen acceptor and bifunctional Au/α-MoC1-x.