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 CO2 reduction reaction (PCO2 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 PCO2 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 (H2 bpydc) and nickel(II) remarkably boosts the visible light-driven PCO2 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 PCO2 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.