A Highly-Efficient and Stable Catalyst based on Co(OH)2@Ni Electroplated on Cu-Metallized Cotton Textile for Water Splitting

Abstract

The concept of using renewable energy to power water electrolyzers is seen as a favorable approach for the production of green and sustainable hydrogen. The electrochemical water splitting can be significantly and efficiently enhanced by using bifunctional catalysts, active towards both the OER (oxygen evolution reaction) and the HER (hydrogen evolution reaction). Herein, a stable and highly performing catalyst based upon hybrid metal/metal hydroxide nanosheet arrays electroplated onto Cu-metallized cotton textile (Co(OH)2@Ni) was designed and fabricated as a bifunctional electrocatalyst for the complete water splitting reactions. It was found that the interconnected α-Co(OH)2 nanosheets were evenly formed onto the metalized cotton textile, and the optimized Co(OH)2@Ni sample exhibited an overpotential of +96 mV at 10 mA cm-2, with excellent stability towards the HER. The as-prepared catalyst also showed superior electrochemical activity and durability towards the OER, which was found to be comparable to conventional precious group metal (PGM)-based catalysts. In addition, when Co(OH)2@Ni were assembled as the electrodes in a water electrolyzer (1 M KOH), a cell voltage of 1.640 V was achieved at a current density of 10 mA cm-2, enabling it to be a promising bifunctional catalyst for water electrolysis in real applications.