Ultrathin two-dimensional π–d conjugated coordination polymer Co3(hexaaminobenzene)2 nanosheets for highly efficient oxygen evolution

Organic two-dimensional (2D) materials with unique optic-electronic properties are attracting great interest for application in functional electronic devices. However, low electronic conductivity and poor stability still are major defects of 2D organic systems. Herein, we demonstrated ultrathin 2D conductive cobalt–hexaaminobenzene metal–organic coordination polymer nanosheets (Co–HAB-NSs) with a thickness of ∼4.5 nm. The as-prepared Co–HAB-NSs exhibit a low overpotential (310 mV @ 10 mA cm−2) and high durability in 1 M KOH. The experimental and computational results show that the high electrocatalytic activity is ascribed to the enhanced electrochemically active surface area as well as the dense and stable catalytic active sites of Co–HAB-NSs.