Amorphous-crystalline catalytic interface of CoFeOH/CoFeP with double sites based on ultrafast hydrolysis for hydrogen evolution at high current density

Abstract A 30 s hydrolysis reaction is used to rapidly synthesize CoFeOH encapsulated CoFeP on iron foam (CoFeOH/CoFeP/IF) with amorphous-crystalline interface and double catalytic sites. Where the loss of phosphorus is inhibited (near 60%) and CoFeOH/CoFeP/IF shows higher hydrogen evolution reaction (HER) property in alkaline media. When drives 100, 500, 1000, 2000 and 3000 mA cm−2, it only requires overpotentials of 114.9, 194.9, 221.8, 249.7 and 266.1 mV in 1.0 M KOH (25 °C) with at least 100-h durability (500 and 1000 mA cm−2). Further simulated industrial tests indicate that the CoFeOH/CoFeP/IF has lower Tafel value and faster HER kinetics in 7.6 M KOH (70 °C). When coupling with NiFe-LDH/IF in a two-electrode system, the voltage of NiFe-LDH/IF (+) || CoFeOH/CoFeP/IF (−) at 2500 mA cm−2 is merely 1.57 V (7.6 M KOH 70 °C). Even in 1.0 M KOH (25 °C) solution, it only needs 1.88 V. This work may provide the guidance for constructing catalytic interface to enhance the HER performances.