Photoinduced Precise Synthesis of Diatomic Ir1 Pd1 -In2 O3 for CO2 Hydrogenation to Methanol via Angstrom-Scale-Distance Dependent Synergistic Catalysis.

The atomically dispersed metal catalysts with full atomic utilization and well-defined site structure hold great promise for various catalytic reactions. However, the single metallic site limits the comprehensive reaction performance in most reactions. Here, we demonstrated a photo-induced neighbour-deposition strategy for the precise synthesis of diatomic Ir1 Pd1 on In2 O3 applied for CO2 hydrogenation to methanol. The proximity synergism between diatomic sites enabled a striking promotion in both CO2 conversion (10.5 %) and methanol selectivity (97 %) with good stability of 100 h run. It resulted in record-breaking space-time yield to methanol (187.1 gMeOH  gmetal -1  hour-1 ). The promotional effect mainly originated from stronger CO2 adsorption on Ir site with assistance of H-spillover from Pd site, thus leading to a lower energy barrier for *HCOO pathway. It was confirmed that this synergistic effect strongly depended on the dual-site distance in an angstrom scale, which was attributed to weaker *H spillover and less electron transfer from Pd to Ir site as the Pd-to-Ir distance increased. The average dual-site distance was evaluated by our firstly proposed photoelectric model. Thus, this study introduced a pioneering strategy to precisely synthesize homonuclear/heteronuclear diatomic catalysts for facilitating the desired reaction route via diatomic synergistic catalysis.