Superhydrophilic Graphdiyne Accelerates Interfacial Mass/Electron Transportation to Boost Electrocatalytic and Photoelectrocatalytic Water Oxidation Activity

Graphdiyne (GDY), with a highly pi-conjugated structure of sp(2)- and sp-hybridized carbon, has triggered a huge interest in water splitting. However, all of the systems perform with no consideration of the surface wettability of GDY. Herein, for the first time, the fabrication of superhydrophilic GDY electrode via air-plasma for oxygen evolution is described. As a representative catalyst, ultrathin CoAl-LDH (CO32-) nanosheets have been successfully assembled onto the superhydrophilic GDY electrostatically. The resulting superhydrophilic CoAl-LDH/GDY electrode exhibites superior activity with an overpotential of approximate to 258 mV to reach 10 mA cm(-2). The turnover frequency (TOF) is calculated to be approximate to 0.60 s(-1) at eta = 300 mV, which is the best record in both CoAl-based and GDY-based layered double hydroxides (LDH) electrocatalysts for oxygen evolution. Density functional theory (DFT) calculations reveal that superhydrophilic GDY has stronger interactions with catalysts and attracts H2O molecules around catalysts, thus facilitating interfacial mass/electron transportation. Further, the fabrication is capable of improving the photoelectrochemical oxygen evolution activity remarkably. The results show the great potential of superhydrophilic GDY to boost water oxidation activity by promoting interfacial mass/electron transportation.