Design strategy of encapsulated nanoplates and nanorods (ID-CoMo): enhanced catalytic activity and sustainability for overall & solar cell water splitting

Abstract

Effective bifunctional ID-CoMo electrocatalysts must be strategically constructed to advance the technology for the conversion and storage of renewable energy. Herein, we report a simple and effective insertion dehydration (ID) method to synthesize encapsulated cobalt–molybdenum oxide (ID-CoMo). The electrical characteristics, geometric morphologies, and chemical composition of ID-CoMo were specifically altered by encapsulation to produce more active sites with potential characteristics and high catalytic activity. In encapsulation, metal–metal interaction induced bi-functionality which leads to a synergistic effect through an improvement of catalyst activity. Among the synthesized catalysts (ID-CoMo, CoO and MoO), ID-CoMo exhibits superior OER and HER activity, delivering small overpotentials of 270 mV (OER) and 125 mV (HER) at 10 mA cm⁻² with low Tafel slopes of 68.3 mV dec⁻¹ (OER) and 72.7 mV dec⁻¹ (HER) and is stable for ∼150 h with minimum potential loss. Furthermore, the enhanced OER and HER activity of ID-CoMo can be attributed to the encapsulated structure which leads to high electrochemical surface area and synergistic effects of Co and Mo metal atoms.