Enhanced photoelectrochemical and photocatalytic performance of SILAR deposited Zn2SnO4 inverse spinels

Abstract

This study presents the synthesis of Zn₂SnO₄ inverse spinel nanostructures using the successive ionic layer adsorption and reaction (SILAR) method, focusing on their photoelectrochemical (PEC) and photocatalytic properties for water oxidation and CO₂ photoreduction. Zn₂SnO₄ films were deposited with varying cycles (30, 60, and 90), resulting in a mixed-phase composition of SnO₂ and Zn₂SnO₄, as evidenced by XRD and Raman analyses. Among these, the film deposited with 60 cycles (60/ZTO) exhibited superior PEC performance, achieving a photocurrent density of 0.624 mA/cm² at 1.23 V vs RHE. This enhanced performance is attributed to its improved crystallinity and surface morphology with an improved charge transfer mechanism. The presence of a higher Sn concentration in the film surface allows the increase in photocatalytic hydrogen production, as, after three days of the test, the hydrogen generation increases four times than the first day of the test, owing to the presence of different Sn and Zn defects where the reaction takes place. Additionally, the 60/ZTO film demonstrated the capability to continuously reduce CO₂ into CH₂O₂ and CH₂O, highlighting its potential for sustainable fuel generation. These findings emphasize the importance of deposition conditions in optimizing Zn₂SnO₄ films for clean energy applications.