Catalytic ammonia synthesis on HY-zeolite-supported angstrom-size molybdenum cluster

The development of new catalysts with high N2 activation ability is an effective approach for low-temperature ammonia synthesis. Herein, we report a novel angstrom-size molybdenum metal cluster catalyst for efficient ammonia synthesis. This catalyst is prepared by the impregnation of a molybdenum halide cluster complex with an octahedral Mo6 metal core on HY zeolite, followed by the removal of all the halide ligands by activation with hydrogen. In this activation, the size of the Mo6 cluster (ca. 7 angstrom) is almost retained. The resulting angstrom-size cluster shows catalytic activity for ammonia synthesis from N2 and H2, and the reaction proceeds continuously even at 200 degrees C under 5.0 MPa. DFT calculations suggest that N0000000000000000000000000000000000000000000000000000111111111111111000000000000000000011111111111111100000000000000000001111111111111110000000000000000000000000000000000000000000000000000N bond cleavage is promoted by the cooperation of the multiple molybdenum sites. A molybdenum halide cluster complex is converted to an angstrom-size metal cluster on HY zeolite. The cluster efficiently catalyzes ammonia synthesis owing to high N2 activation ability brought by cooperation of the multiple molybdenum sites.