Engineering cobalt sulfide/oxide heterostructure with atomically mixed interfaces for synergistic electrocatalytic water splitting
Xiaoyang Wang, Yu He, Xiaopeng Han, Jun Zhao, Lanlan Li, Jinfeng Zhang, Cheng Zhong, Yida Deng, Wenbin Hu
Abstract
It remains challenging to develop economical and bifunctional electrocatalysts toward oxygen/hydrogen evolution reactions (OER/HER). Herein, we construct Co9S8 nanoflakes decorated Co3O4 nanoarrays with enriched heterogeneous interface zones on Ni foam (Co9S8@Co3O4/NF) via a novel step-wise approach. The Co9S8@Co3O4/NF hybrid manifests excellent performance with low overpotentials of 130 mV for HER (10 mA·cm−2) and 331 mV for OER (100 mA·cm−2), delivering a small voltage of 1.52 V for water splitting at 10 mA·cm−2 as well as outstanding catalytic durability, which surpasses precious metals and previously reported earth-abundant nanocatalysts. Further experimental and theoretical investigations demonstrate that the excellent performance is attributed to the followings: (i) Highly conductive Ni facilitates the efficient charge transfer; (ii) porous core-shell nanoarchitecture benefits the infiltration and transportation of gases/ions; (iii) heterogeneous interface zones synergistically lower the chemisorption energy of hydrogen/oxygen intermediates. This work will shed light on the controllable synthesis and engineering of heterostructure nanomaterials for clean energy storage and conversion technologies.