Prussian blue analogue-derived CoP nanocubes supported on MXene toward an efficient bifunctional electrode with enhanced overall water splitting

CoP nanoparticles confined in PBA-derived nanocubes supported on MXene for efficient electrocatalytic water splitting. [Display omitted] •Simply synthesis method: Simple coprecipitation-phosphatization two steps to synthesis the heterojunction between CoP and Ti3C2Tx MXene (CoP/Ti3C2Tx).•Outstanding electrochemical performance: The catalyst CoP/Ti3C2Tx exhibits impressive overpotentials of 103 mV and 312 mV for HER and OER, respectively, to afford 10 mA cm−2 in 1.0 M KOH and maintain for 24 h.•Thorough theoretical calculation verification: The DFT calculations reveal that the introduction of Ti3C2Tx MXene can significantly enhance the electrochemical performance towards water splitting. The exploration of bifunctional catalyst with economic, durable, and efficient performance plays a crucial role to boost both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in overall water splitting. Herein, we report a feasible strategy to design effective heterostructure between CoP and Ti3C2Tx MXene (denoted as CoP/Ti3C2Tx). This approach allows for the growth of CoP nanoparticles with uniform size of 5 nm on the Ti3C2Tx MXene, further enhancing the water electrolysis efficiency. The CoP/Ti3C2Tx bifunctional catalyst demonstrates an exceptional HER activity with a satisfactory overpotential of 103 mV at 10 mA cm−2, and also can drive 10 mA cm−2 for OER with the overpotential of 312 mV in 1.0 M KOH. Moreover, the CoP/Ti3C2Tx-based electrolyzer exhibits high electrochemical stability for 24 h with a low required voltage of 1.66 V at 10 mA cm−2. The density functional theory (DFT) calculations reveal that the introduction of Ti3C2Tx MXene significantly adjusts d-band center towards Fermi level and expand total density of states, resulting in great electrical conductivity, enhanced water adsorption, and activation. This study provides an available mode for effective design and construction of non-noble-metal-based dual-functional catalyst toward practical energy conversion.