Bimetallic Mn and Cr co-doped nickel cobalt phosphide nanoneedle arrays as bifunctional electro catalysts for overall water splitting

The study of high‐efficiency and economical non‐noble metal bifunctional catalysts for water electrolysis is still critical for large‐scale practical application of hydrogen energy. In this research, bimetallic Mn and Cr co-doped nickel cobalt phosphide (MnCr-NiCoP) electro catalyst with vertical nanoneedle array structure self-supported on conductive nickel foam electrode is fabricated by a classical two-step hydrothermal and phosphating route. 3D vertical nanoneedle arrays present the diameter of ∼40 nm in cross section and are constituted by plentifully diminutive nanoparticles of ∼10 nm size, which can afford a good deal of interspaces and available locations to promote electrolyte transport and electro catalytic reaction. The results prove that Mn and Cr co-doping can regulate the local electronic structure, hearten the electron transfer, as well as improve the intrinsic activity. Furthermore, the acuminate needle-like nanowire is weak in the adsorption of bubble to enhance the desorption of procreant gas. The stabilized MnCr-NiCoP catalyst demonstrates relatively low over potentials of 234.8 and 70.2 mV at 10 mA cm⁻² for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The electrolyzer of MnCr-NiCoP as both cathode and anode requires a cell voltage of 1.42 V at 10 mA cm⁻² while has tolerable durability for 60 h. This work not only recommends an appealing and cost-effective catalytic material, but also offers a pivotal strategy for the design and synthesis of foundational-metal-based electro catalysts.