Engineering active sites in binary PrCoO₃/Mn₂V₂O₇ heterointerface embedded in phosphorus-doped biochar for boosting pH universal water splitting

For water splitting, rationally designing highly efficient and robust bifunctional photoelectrocatalysts is crucial. The purpose of this work is to produce a PrCoO₃/Mn₂V₂O₇ @PBC nanocomposite by increasing the number of active catalytic sites of praseodymium cobaltite (PrCoO₃) for electrochemical water splitting. A binary PrCoO₃/Mn₂V₂O₇ heterostructure was synthesized using a solvothermal technique and then loaded onto phosphorus-doped biochar (PBC). Compared to pure samples, nanocomposites of PrCoO₃/Mn₂V₂O₇@PBC exhibited better electrocatalytic activity, with the highest activity when light was illuminated on the material. At a current density of 10 mAcm⁻² in alkaline media, the PrCoO₃/Mn₂V₂O₇ @PBC needs low overpotentials of 121 and 282 mV for hydrogen and oxygen evolution processes (HER and OER), respectively. Moreover, this material exhibits excellent kinetics, a high electrochemically active surface area, low charge transfer resistance, and great long-term stability for the OER and HER. The overall water splitting process achieved a low cell voltage of 1.65 V at 3 mA/cm² when PrCoO₃/Mn₂V₂O₇ @PBC were used as self-supported electrodes. The enhanced performance of PrCoO₃/Mn₂V₂O₇ @PBC can be attributed to three main factor (i) firstly, the presence of active multi-metal sites that enhance each other’s effects (ii) the high conductivity of phosphorus doped biochar (PBC) that facilitates favourable electron transfer (iii) and the increased number of active sites on the catalyst surface caused by the homogeneous anchoring of PrCoO₃/Mn₂V₂O₇ on phosphorus doped biochar (PBC).