Dendritic FeCoNiP@HEAs Mott-Schottky heterojunction for efficient overall water splitting

Engineering the electronic structure via heterojunction construction and morphological control effectively advances electrocatalysis. A dendritic porous FeCoNiP@HEAs Mott-Schottky heterojunction is fabricated by electrodeposition as bifunctional catalysts. The heterojunction modulates the electronic structure, optimizing the adsorption energy of reaction intermediates. The superhydrophilic/superhydrophobic surface minimizes bubble adhesion, while the dendritic tip architecture enriches electrolyte-active site contact. Consequently, the FeCoNiP@HEAs electrode exhibits outstanding activity and durability. In alkaline electrolyte, overpotentials for OER and HER are only 205 mV and 152 mV at 100 mA cm −2 , respectively. The two-electrode cell achieves stable overall water splitting at 1.66 V for 60 h at 100 mA cm −2 . XPS confirms that the heterojunction effectively regulates the interfacial electronic structure, with stronger modulation for phosphide/HEA composites than for phosphide/ternary alloy counterparts. High-valent metal ions further enhance performance. DFT calculations verify the Mott-Schottky heterojunction, which optimizes d-band center, reduces adsorption energy, accelerates interfacial electron transfer, and boosts catalytic activity.