Natural-wood-fiber-assisted synthesis of Ni2P embedded in P-doped porous carbon as highly active catalyst for urea electro-oxidation

Defect and interface engineering has been established as efficient methods for altering the electrical structure and improving the activity of electrocatalysts. Here, a rational design architecture consisting of Ni2P nanoparticles embedded in P-doped carbonized wood fibers (Ni2P/PCWF) is synthesized by simultaneous carbonization and phosphorization. A synergistic enhancement effect between electronic structure manipulation and interface regulation is observed in Ni2P/PCWF during the urea oxidation reaction (UOR). First, the P doping of carbon can optimize the electronic structure of Ni2P/PCWF. Second, the charge transport process is aided by the Ni2P nanoparticles embedded in the PCWF. Lastly, electron transfer can be accelerated by the in-situ formed heterogeneous interface between metal phosphides and metal hydroxides (hydroxyl oxides). Due to the synergy of the structural and electrical modulation, Ni2P/PCWF exhibits remarkable electrocatalytic properties toward the UOR under alkaline conditions. It only requires 1.34 V (vs. RHE) to achieve a current density of 50 mA cm−2, and the increase in potential at 10 mA cm−2 for 70 h is insignificant (≈2.9%). This work supports the development of new strategies using sustainable, renewable wood fibers to develop excellent UOR catalysts for energy-saving H2 generation.