Interfacial Dual Sites on Mo-MXene-Based Catalysts for Highly Efficient Ammonia Synthesis under Mild Conditions

The development of nonprecious metal (NPM) catalysts for ammonia (NH 3 ) synthesis under mild conditions remains highly challenging, since the competitive adsorption of reactants (N 2 and H 2 ) and NH 3 at active sites is a trade-off and detrimental to NH 3 synthesis. Herein, we report a series of ZrH 2 -modified Mo-MXene (MX) catalysts for efficient NH 3 synthesis, leveraging the synergistic effect of interfacial dual sites. The developed 40MX-ZrH 2 catalyst shows a high NH 3 synthesis rate of 15.7 mmol g –1 h –1 at 400 °C and 1 MPa, outperforming most reported NPM-based catalysts. Our studies demonstrate that the ball-milling process decreases the grain size of both Mo 2 CT x and ZrH 2, thereby generating abundant interfacial dual sites. Although Mo-MXene is highly active for N 2 activation through a dissociative route, its strong affinity for N species impedes H 2 activation and NH 3 desorption. The incorporation of ZrH 2 not only is responsible for H 2 activation and storage but also donates electrons to Mo 2 CT x to accelerate NH 3 desorption. Thus, the interfacial dual sites in MX-ZrH 2 synergistically promote the activation of N 2 and H 2 along with the desorption of NH 3, enabling efficient NH 3 synthesis under mild conditions.