A High-Performance Bimetallic Ru 1 Mo 6 Active Site for Thermal Ammonia Synthesis under Mild Conditions

Ammonia (NH 3 ) synthesis is among the greatest discoveries in human history. While dinitrogen (N 2 ) is converted in nature under ambient conditions to NH 3 through an associative mechanism at the FeMoco active site of nitrogenase, the industrialized Haber–Bosch process involves an N 2 dissociative mechanism on the C 7 site of iron or the B 5 site of ruthenium, which requires harsh conditions of high temperatures (430–500 °C) and high pressures (10–30 MPa). Here, we report a new active site of Ru 1 Mo 6 bimetallic single-cluster anchored on Mo 2 CT x MXene for efficient NH 3 synthesis. This highly stable catalyst can achieve N 2 -to-NH 3 thermal synthesis under mild conditions ( T = 50 °C and P = 0.1 MPa). An exceptionally high NH 3 production rate of 3230 mmol g Ru –1 h –1 with >1000 h of long-term stability has been achieved at 400 °C and 1 MPa, which is roughly three times higher than those of highly dispersed Ru catalysts ever reported. This new catalyst featuring an atomically precise single-cluster active site holds promise for designing robust catalytic systems for N 2 -to-NH 3 thermal conversion under mild conditions.