Ligand-restricted synthesis of highly paired dual-atom catalysts.

Dual-atom catalysts (DACs) exhibit high catalytic activity and metal utilization, alongside structural diversity with a wide range of catalytic site configurations. These features position DACs as promising candidates for energy conversion technologies. However, the precise control over atomic dispersion, pairing ratios and interatomic distances-which critically influence their multifunctional catalytic behavior-remains a formidable challenge. Here we developed a ligand-restricted strategy for the precise synthesis of highly paired DACs with tunable atomic distances. This was accomplished by coordinating diamine ligands with dual-metal precursors, restricting the pairing and relative positions of two metal atoms on two-dimensional graphitic carbon nitride. The atomic pairing ratio exceeded 82%, and the atomic pairing distance was controlled by the chain length of the diamine ligand. As a demonstration, the paired Pt1-Au1 DACs exhibited almost threefold enhancement in catalytic activity for nitrate reduction to ammonia compared with their unpaired counterparts. This work introduces an effective strategy for the atomic-scale fabrication of complex catalysts as well as provides valuable insights into nanoscale reaction mechanisms in heterogeneous catalysis.