Designing Donor–Acceptor Interfaces with Built-In Electric Potential Using Hierarchically Grown NiTe–CeO₂ Heterostructure for Efficient Water Oxidation

Designing a non-noble metal based heterojunction electrocatalyst with outstanding catalytic activity and long-term stability is essential for efficient oxygen evolution reaction (OER). Herein, we have strategically designed a NiTe/CeO₂ heterojunction based on a donor-acceptor approach, wherein CeO₂ functions as the electron donor and NiTe as the electron acceptor. Kelvin probe force microscopy (KPFM) measurements revealed that the work functions of NiTe and CeO₂ facilitate the charge transfers upon interfacial coupling between NiTe and CeO₂. This interfacial synergy induces the formation of a built-in electric field at the heterojunction, which effectively modulates the surface electronic structure of NiTe through strong interfacial interactions with CeO₂, achieving an overpotential of 263 mV at 10 mA cm^-2 and a Tafel slope of 81 mV dec^-1 for the OER. The formation of the heterojunction led to an increased electrochemical active surface area (a <i>C</i>_dl value of 10.5 μF cm^-2) and a reduced charge-transfer resistance (1 Ω), which results in improved turnover frequency (3 s^-1) as compared to the bare counterpart. Through the distribution of relaxation time (DRT) analysis, the extracted time constants corresponding to different relaxation processes reveal an enhanced charge-transfer kinetics across the interfaces, enhancing OER kinetics.