Nickel Phosphide Clusters Sensitized TiO<sub>2</sub> Nanotube Arrays as Highly Efficient Photoanode for Photoelectrocatalytic Urea Oxidation
Ying Tao, Zhong Ma, Wenchao Wang, Chi Zhang, Lanlan Fu, Qiong Zhu, Yanliu Li, Guisheng Li, Dieqing Zhang
Abstract
Abstract The photoelectrocatalytic urea oxidation reaction (PEC‐UOR) holds a great promise for the wastewater remediation and energy production. However, the low efficiency of semiconductor/cocatalysts type photoanodes for UOR restricts their applications in photoelectrocatalytic system. Herein, a new semiconductor/cocatalyst, Ni 2 P clusters sensitized TiO 2 nanotube arrays photoanode (Ni 2 P/TiO 2 ‐NTAs) for PEC‐UOR with high efficiency are developed. The 1D TiO 2 ‐NTAs structure accelerates urea molecules diffusion and promotes CO 2 gas release at the electrode interface. Meanwhile, Ni 2 P is also beneficial to urea molecule absorption and CO 2 desorption and enable to lower the energy barrier for amine (NH) dehydrogenation. Furthermore, the robust interfacial charge transfer pathway between Ni 2 P and TiO 2 interface promotes the separation of photogenerated electrons and holes and the transfer of photogenerated electrons from Ni 2 P to TiO 2 . Therefore, this photoanode shows excellent PEC‐UOR performance with the potential of 1.43 V versus reversible hydrogen electrode (RHE) when the current density reaches 10 mA cm −2 , which is much lower than that of 2.24 V versus RHE and 1.58 V versus RHE for TiO 2 ‐NTAs and Ni(OH) 2 /TiO 2 ‐NTAs, respectively.