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 V_RHE, 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.

Keywords

heterostructure / interfacial charge separation / perovskite quantum dots / photoelectrochemical cell / water splitting

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