Cost-Effective 2D Ultrathin Metal-Organic Layers with Bis-Metallic Catalytic Sites for Visible Light-Driven Photocatalytic CO 2 Reduction.

As novel generated 2D materials, metal-organic layers (MOLs) have recently emerged as a potential platform for photocatalytic CO 2 reduction reaction (PCO 2 RR). Such 2D structures negate the blemish of low-density catalytic sites and low electron transmission efficiency on the surface of metal organic frameworks (MOFs), while retaining the advantage of low expenditure when using earth-abundant metal nodes and meritorious applicability in the PCO 2 RR. Herein, it is reported that the 2D ultrathin layer material with bis-metallic catalytic sites (Ni-O metal node and the Ni-N metal site) from bidentate ligand 2,2'-bipyridine-5,5'-dicarboxylate (H 2 bpydc) and nickel(II) remarkably boosts the visible light-driven PCO 2 RR performance with a CO yield of 2400 mmol g -1 for 18 h and a selectivity up to 99 %. Consequently, the effects of morphology, catalytic sites and intrinsic properties on PCO 2 RR efficiency have been investigated in detail. In this context, the ultrathin layer structure has been elucidated as the key point to facilitate electron transfer efficiency. Notably, the bis-metallic catalytic sites with reasonable distance between two adjacent metals presumably induce synergistic effect and offer a guiding ideology for further designing high performance photocatalysts.