Amorphous carbon modulated-quantum dots NiO for efficient oxygen evolution in anion exchange membrane water electrolyzer
Benjin Jin, Qian Wang, Jani Sainio, Viktoriia A. Saveleva, Hua Jiang, Junjie Shi, Basit Ali, Antti‐Jussi Kallio, Simo Huotari, Dage Sundholm, Nana Han, Tanja Kallio
Abstract
Developing efficient electrocatalysts of elements that are abundant on earth crust is crucial for green hydrogen generation technologies. In particular, the oxygen evolution reaction (OER) under alkaline plays a key role in anion exchange membrane (AEM) electrolyzer to produce green hydrogen but suffers from low kinetic. Herein, nickel oxide quantum dots with highly uniform size distribution on ultrathin amorphous carbon nanosheets (NiO dots/a-carbon) were successfully prepared by a one-step method. Introducing NiO quantum dots onto amorphous carbon modifies the local coordination environment of Ni promoting it into a higher valence state. Benefitting from the promoted Niδ+ (2<δ<3) and the strong connection between Ni and amorphous carbon though Ni-O-C and Ni-C bonds, NiO dots/a-carbon exhibits excellent activity and stability towards OER in 0.1 M KOH using the rotating disk electrode. Moreover, a challenging current density of 500 mA cm−2 is achieved at 1.7 V with a lab-scale AEM electrolyzer.