Orchestrating Ni - N bonding interfaces to accelerate charge transfer in amorphous nickel hydroxide/sulfur-doped...

Precise engineering of interface charge transfer is crucial for enhancing photocatalytic performance. Herein, a novel amorphous nickel hydroxide/sulfur-doped polyimide (Ni(OH)₂/SPI) S-scheme heterojunction with ordered interface charge transfer characteristics was designed. X-ray Absorption Fine Structure (XAFS) and fourier transform infrared spectroscopy (FT-IR) together confirmed the formation of new Ni - N bonds at the interface. Notably, the Ni(d) - N(p) bonds formed by the hybridization of the d orbitals of Ni with the p orbitals of N nitrogen precisely connect the conduction band (CB) of Ni(OH)₂ and the valence band (VB) of SPI. These Ni(d) - N(p) bonds not only serve as charge transmission channels but also effectively enhance the efficiency of photogenerated carrier separation. Meanwhile, the long-range disorder and short-range order characteristics of amorphous Ni(OH)₂, effectively shorten the charge transfer distance in Ni(OH)₂/SPI, and regulate the local electronic structure at the interface, thereby enhancing the interface electronic dynamics. The experimental and theoretical results indicate that there is a directional charge migration at the interface between Ni(OH)₂ and SPI. Benefiting from the engineered interfacial pathways, the hydrogen production rate and the degradation activity of methyl orange (MO) by Ni(OH)₂/SPI photocatalysis were significantly enhanced. This study provided a new insights for the rational design of efficient photocatalytic systems through interface chemical bonding engineering at the atomic level.