All-Inorganic Perovskite@SiO2 Quantum Dots for Amplifying the Interfacial Electric Field on WO3 Toward Enhanced Photoelectrochemical Water Splitting

Abstract

All-inorganic halide perovskite quantum dots (PQDs) encounter significant challenges related to degradation and self-oxidation in aqueous electrolytes, which remain critical obstacles for their efficient utilization in photoelectrochemical (PEC) water oxidation. In this study, we demonstrate the hybridization of zero-dimensional CsPbBr3 PQDs with a SiO2 shell (PQD@SiO2) and the direct harnessing of PQD@SiO2 on a two-dimensional WO3 nanoflake photoanode for boosting PEC water splitting. The ultra-thin SiO2 shell protects the PQDs from the aqueous environment and suppresses undesirable charge recombination. Incorporating PQD@SiO2 enhances light harvesting and manipulates photogenerated charges, amplifying the interfacial electric field of the WO3 photoanode to facilitate PEC water oxidation kinetics. Consequently, PQD@SiO2-incorporated WO3 (PQD@SiO2/WO3) exhibits 2.2-fold higher PEC performance compared to pristine WO3 at 1.23 VRHE, with long-term durability over 12 h and a remarkable Faradaic efficiency of 85.5% for overall solar water splitting to produce H2 at 1.23 V under 1 sun illumination. This novel strategy of a heterostructure consisting of PQDs passivated by an ultra-thin SiO2 shell on a WO3 photoanode paves the way for improving PEC water splitting and efficient hydrogen production.