Dual co-catalysts decorated Zn-WO3 nanorod arrays with highly efficient photoelectrocatalytic performance.

WO 3 has been recognized as a promising photoanode for the conversion of solar energy to hydrogen energy through photoelectrochemical water splitting. Herein, Zn-WO 3 nanorod arrays were synthesized by a two-step solvothermal method and then decorated with FeOOH and CoOOH dual co-catalysts layer through electrodeposition. Characterizations confirm the presence of abundant surface oxygen vacancies in Zn-WO 3 , leading to the increase of carriers with high mobility and thus improving the separation (from 63.7% to 92.0%) and injection (from 61.9% to 95.3%) efficiency of carriers. Meanwhile, the dual co-catalysts layer accelerates the transfer of the hole at the interface and inhibits the photocorrosion. Consequently, the optimal 9-Zn-WO 3 -Fe/Co exhibits the photocurrent of 3.63 mA/cm2 at 1.23 V vs. RHE, which is 90.7% of the theoretical value of WO 3 (ca. 4.0 mA/cm2). This work constructs a highly efficient and stable WO 3 photoanode by an integration strategy of transition metal doping and dual co-catalysts modification. [Display omitted] • A facile strategy to prepare Zn-doped WO 3 with dual co-catalysts is developed. • Multiple characterizations confirm the introduction of surface oxygen vacancies. • Effective carrier separation and transfer are achieved through the bulk and surface modification of WO 3. • The photocurrent density of 9-Zn-WO 3 -Fe/Co reaches 90.7% of the theoretical value of WO 3. [ABSTRACT FROM AUTHOR]