In-Situ Conversion of Co-CoN Nanowires into Ultrathin 2D Nanosheets for High Effective Catalytic Hydrogenation The design of 2-dimentional (2D) CoN-based thin sheets is promising in the catalytic field. The usual synthesis based on the thermal treatment of the hydroxide sheets undergoes the enhanced particle size and thick sheets. Here, we have showed a novel route based on an in-situ conversion of Co-CoN nanowires into ultra-thin sheets for an effective catalytic hydrogenation.