Ag nanoparticles anchored organic/inorganic Z-scheme 3DOMM-TiO2–x-based heterojunction for efficient photocatalytic and photoelectrochemical water splitting

Abstract

Narrow spectral response, low charge separation efficiency and slow water oxidation kinetics of TiO2 limit its application in photoelectrochemical and photocatalytic water splitting. Herein, a promising organic/inorganic composite catalyst Ag/PANI/3DOMM-TiO2–x with a three-dimensional ordered macro-and meso-porous (3DOMM) structure, oxygen vacancy and Ti3+ defects, heterojunction formation and noble metal Ag was designed based on the Z-scheme mechanism and successfully prepared. The Ag/PANI/3DOMM-TiO2–x ternary catalyst exhibited enhanced hydrogen production activity in both photocatalytic and photoelectrochemical water splitting. The photocatalytic hydrogen production rate is 420.90 μmol g–1 h–1, which are 19.80 times and 2.06 times higher than the commercial P25 and 3DOMM-TiO2, respectively. In the photoelectrochemical tests, the Ag/PANI/3DOMM-TiO2–x photoelectrode shows enhanced separation and transfer of carriers with a high current density of 1.55 mA cm–2 at equilibrium potential of 1.23 V under simulated AM 1.5 G illumination, which is approximately 5 times greater than the 3DOMM-TiO2. The present work has demonstrated the promising potential of organic/inorganic Z-scheme photocatalyst in driving water splitting for hydrogen production.