Photocatalytic hydrogen production via solar-driven water splitting using MoO3/Ti3C2-supported ZnFe2O4 photocatalyst

Abstract

The development of efficient photocatalysts for photocatalytic hydrogen evolution is essential for advancing to a reliable and sustainable source of environmentally friendly energy. In this quest, ZnFe₂O₄ is an important photocatalyst for applications in solar energy conversion due to its visible light-sensitive bandgap, appropriate energy bands, photochemical and thermal stability, and magnetic retrievability. However, its hydrogen evolution rate is limited due to poor electron conductivity and particle agglomeration. Herein, we prepared a composite of ZnFe₂O₄, MoO₃ and Ti₃C₂ via the ultrasonication-assisted wet impregnation method. The crystal structure, morphology, and optoelectronic properties of the composite were analysed. The optimized composite displayed exceptional photocatalytic performance, achieving a peak H₂ evolution rate of 30,129 μmolg⁻¹h⁻¹ under solar light exposure with methanol as a sacrificial agent, a 286-fold enhancement over pristine ZnFe₂O₄. This notable enhancement in photoactivity is attributed to the reduction in bandgap energy from 2.00 to 1.77 eV and the introduction of MoO₃ and Ti₃C₂ which led to significant photoluminescence quenching, promoting separation and transfer of charge carriers, thereby boosting the photocatalytic performance of ZnFe₂O₄. MoO₃ helped limit ZnFe₂O₄ agglomeration, while Ti₃C₂ facilitated electron transfer and suppressed charge recombination. The optimized photocatalyst also demonstrated outstanding stability, maintaining 99 % of its activity after 16 h and 4 consecutive cycles. This study provides new insights into the design of nanocomposites, demonstrating a hydrogen evolution rate that is significantly higher than those reported in previous studies on ZnFe₂O₄-based photocatalysts.