Cu2S@NiFe layered double hydroxides nanosheets hollow nanorod arrays self-supported oxygen evolution reaction electrode for efficient anion exchange membrane water electrolyzer

Herein, we prepared highly active self-supported Cu2S@NiFe layered double hydroxides nanosheets (LDHs) oxygen evolution reaction (OER) electrode (Cu2S@NiFe LDHs/Cu foam) with three-dimensional (3D) multilayer hollow nanorod arrays structure, which is composed of the outer layer (two-dimensional (2D) NiFe LDHs) and the inner layer (one-dimensional (1D) Cu2S hollow nanorod arrays). The unique structure of NiFe LDHs and Cu2S hollow nanorod composites can expose more active sites, and simultaneously promote electrolyte penetration and gas release during the water electrolysis process. Thus, the Cu2S@NiFe LDHs/Cu foam electrode exhibits a significant OER performance, with the overpotentials of 230 and 286 mV at 50 and 100 mA cm−2, respectively. Anion exchange membrane water electrolyzer (AEMWE) with the prepared electrode can attain a voltage of 1.56 V at the current density of 0.50 A cm−2, showing a good performance that is comparable to the-state-of-the-art AEMWE in 1 M KOH. In addition, the AEMWE can be run for 300 h at the current density of 0.50 A cm−2. The high performance and good stability of AEMWE are attributed to the special structure of the OER electrode, which can prevent the agglomeration of nanosheets and thus expose more active sites at the edge of the nanosheets.