Pt Single Atom‐Doped Triphasic VP‐Ni₃P‐MoP Heterostructure: Unveiling a Breakthrough Electrocatalyst for Efficient Water Splitting

Enhancement of an alkaline water splitting reaction in Pt-based single-atom catalysts (SACs) relies on effective metal-support interactions. A Pt single atom (Pt_SA)-immobilized three-phased Pt_SA@VP-Ni₃P-MoP heterostructure on nickel foam is presented, demonstrating high catalytic performance. The existence of Pt_SA on triphasic metal phosphides gives an outstanding performance toward overall water splitting. The Pt_SA@VP-Ni₃P-MoP performs a low overpotential of 28 and 261 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at a current density of 10 and 25 mA cm^-2, respectively. The Pt_SA@VP-Ni₃P-MoP (+,-) alkaline electrolyzer achieves a minimum cell voltage of 1.48 V at a current density of 10 mA cm^-2 for overall water splitting. Additionally, the electrocatalyst exhibits a substantial Faradaic yield of ≈98.12% for H₂ and 98.47% for O₂ at a current density of 50 mA cm^-2. Consequently, this study establishes a connection for understanding the active role of single metal atoms in substrate configuration for catalytic performance. It also facilitates the successful synthesis of SACs, with a substantial loading on transition metal phosphides and maximal atomic utilization, providing more active sites and, thereby enhancing electrocatalytic activity.