Nitrate electroreduction to ammonia catalysed by atomically precise Au 28 Cu 12 clusters.

A novel bimetal cluster [Au 28 Cu 12 (SR) 24 ](PPh 4 ) 4 (SR = 2,4-dichlorothiophenol) has been successfully synthesized, which can be viewed as a Au 4 @Au 24 core and four trimeric Cu 3 (SR) 6 staples. Compared to monometallic Au 28 (TBBT) 20 and Cu 28 (CHT) 18 (PPh 3 ) 3 clusters, the [Au 28 Cu 12 (C 6 H 4 Cl 2 S) 24 ](PPh 4 ) 4 cluster has much higher catalytic efficiency for nitrate electroreduction to ammonia.