A series of metal catecholate candidates, which could potentially be incorporated into metal-organic frameworks (MOFs), have been screened using quantum chemical methods to identify the most promising metals for ammonia capture in the presence of water. Binding energies and free energies of binding were calculated first for ammonia and water separately with a series of metal catecholates. Further analysis was performed to understand the competitive binding of ammonia and water with the metal catecholates. Among the metals studied, Pt- and Cu-catecholates are the best candidates for ammonia capture under humid conditions, whereas the Cu-catecholate is especially promising under dry conditions.