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 TiO 2 limit its application in photoelectrochemical and photocatalytic water splitting. Herein, a promising organic/inorganic composite catalyst Ag/PANI/3DOMM-TiO 2– x with a three-dimensional ordered macro-and meso-porous (3DOMM) structure, oxygen vacancy and Ti 3+ defects, heterojunction formation and noble metal Ag was designed based on the Z-scheme mechanism and successfully prepared. The Ag/PANI/3DOMM-TiO 2– 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-TiO 2 , respectively. In the photoelectrochemical tests, the Ag/PANI/3DOMM-TiO 2– 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-TiO 2 . The present work has demonstrated the promising potential of organic/inorganic Z-scheme photocatalyst in driving water splitting for hydrogen production. A promising organic/inorganic composite catalyst Ag/PANI/3DOMM-TiO 2– x was designed for both photocatalytic and photoelectrochemical water splitting hydrogen production. The activity was improved through the three-dimensional ordered macro- and meso-porous structure, formation of Z-scheme heterojunction, introduce of Ti 3+ defects and oxygen vacancies as well as the SPR effect of noble metal Ag NPs.