Electrocatalytic Hydrogen Precipitation Performances of B and Ce Codoped CoP/NiCoP over a Wide pH Range

Exploring efficient, low-cost, and pH-versatile electrocatalysts for hydrogen precipitation is vital for the development of practical hydrogen production via water electrolysis. However, most existing electrocatalysts suffer from limitations such as high overpotentials, a reliance on expensive noble metals, or poor stability under extreme pH conditions, hindering their practical application. Among the many electrocatalytic materials, transition metal phosphides (TMPs) are considered a promising class of hydrogen evolution reaction (HER) catalytic materials due to their abundant reserves and tunable electronic structures. Despite the demonstrated potential of TMPs in electrolytic water-to-hydrogen reactions in recent years, there are still several issues that must be addressed, including the insufficient exposure of active sites, high charge-transfer barriers under full pH conditions, and poor long-term stability. In this work, B and Ce codoped CoP/NiCoP heterostructured nanoarrays were grown on nickel foam. This codoped catalyst exhibits a larger electrochemically active surface area, which significantly improves its HER kinetics and charge-transfer ability. The B, Ce codoped CoP/NiCoP catalyst presents good catalytic performance over a wide pH range: at a current density of 10 mA cm^-2, overpotentials of 89, 123, and 44 mV are achieved under acidic (0.5 M H₂SO₄), neutral (1 M PBS), and alkaline (1 M KOH) conditions, respectively. Moreover, the catalyst exhibits Tafel slopes of only 55 mV dec^-1 (0.5 M H₂SO₄), 105 mV dec^-1 (1 M PBS), and 51 mV dec^-1 (1 M KOH). After 20 h of stability testing at a current density of 100 mA cm^-2, current density retention rates of 85, 60, and 92% are achieved under acidic, neutral, and alkaline conditions, respectively. This study provides new insights into the implementation of a cation-anion codoping strategy for the design and preparation of low-cost, high-efficiency electrocatalysts.