Nickel phosphate-based materials with excellent durability for urea electro-oxidation

- Nickel phosphates (NiPO) with different structures are synthesized.
- The electrochemical performance of porous film NiPO is excellent.
- After 96-hour, the electrochemical activity of NiPO retains 97.47%.
- The NiPO is stable even after 134 days of storage at ambient conditions.

Nickel phosphates (NiPO-a, NiPO-b, NiPO-c, NiPO-d) with different structures are developed by different methods. The mesostructure of NiPO-a is composed of less-ordered nanotubes of different lengths and NiPO-b, NiPO-c are arranged by a kind of flower-like nanosheet porous film. While, NiPO-d is composed of stacked nanocrystals. These nickel phosphates are examined by electrochemical tests to investigate the electrochemical activity of urea oxidation under alkaline conditions. Compared with commercial NiO, the four kinds of nickel phosphates have a more negative initial oxidation potential, which are more likely to react chemically with urea. As to NiPO-c, the highest oxidation current density for urea oxidation and superior stability are observed. During a 96-hour amperometric i-t test, the surface of NiPO-c modified fluorine-doped tin dioxide transparent conductive glass (FTO) electrode does not fall off, and the electrochemical activity just reduces 2.52% compared with the maximum value. NiPO-c has great potential for large-scale production in the field of urea-rich wastewater treatment and energy consumption.

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