Oriented Growth of Parallel-Standing Bimetallic Nanosheet Arrays for Enhanced Charge Transfer

Fabricating highly oriented 2D nanosheet arrays is crucial for boosting their performance in electronics, catalysis, optics, and energy conversion, while it remains a challenge due to the high surface energy often leads to random aggregation or interlaced structure. In this study, it is found that the exposed facet of Fe2O3 can greatly influence the interface growth arrangement of bimetallic hydroxide (NiCo(OH)2) nanosheets. The NiCo(OH)2 nanosheets tend to parallel-standing on the cubic and spindle Fe2O3 while random- and interlaced-standing on the Fe2O3 hexagonal nanoplates and microspheres. The theoretical simulation further indicates the orientation of deposited hydroxide sheets is decided explicitly by the interfacial lattice match/mismatch. Compared to the common interlaced structure of nanosheets, the parallel-standing nanosheet arrays reduce grain boundaries and improve the charge transfer efficiency. As a result, the derived NiCoP cages exhibit a promising oxygen evolution reaction performance with an overpotential of 255 mV at 10 mA cm-2, and the maximum current density of 400 mA cm-2 with the overpotential of 319 mV. The parallel-standing of NiCo(OH)2 nanosheets on Fe2O3 induced by crystal lattice-matching principle with reduced grain boundaries can enhance the electron transfer and improve the electrochemical catalytic performance. image