Metal-organic frameworks derived reverse-encapsulation Co-NC@Mo2C complex for efficient overall water splitting

Developing low-cost, highly active, and stable bifunctional electrocatalysts is a challenging issue in electrochemical water electrolysis. Herein, we develop a simple metal organic frameworks (MOFs) based approach to prepare bifunctional [email protected] Mo2C complex catalysts. Differently from traditional carbon encapsulated functional nanomaterials, herein the carbon-based framework derived carbonitride and Co nanoparticles (Co-NC) are encapsulated with Mo2C. Benefiting from the unique reverse-encapsulation structure and synergetic effects of Mo2C and Co-NC, the [email protected]2C catalyst shows superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance. In alkaline media, it affords the current density of 10 mA cm−2 at low overpotentials of 99 mV and 347 mV for HER and OER, respectively. Interestingly, due to a reversed encapsulation structure where Co nanoparticles are protected by Mo2C, it leads to an outstanding HER catalytic activity (a low overpotential of 143 mV) and stability in acidic solutions. Remarkably, when employed as both the cathode and anode for overall water splitting, a low cell voltage of 1.685 V is required to reach the current density of 10 mA cm−2 in alkaline media with excellent stability, making the [email protected]2C an efficient non noble metal bifunctional electrocatalyst toward water splitting.