Stable and efficient PbS quantum dot photoelectrodes enable photoelectrochemical hydrogen production without sacrificial agents

Abstract

Chalcogenides are promising materials for photoelectrochemical (PEC) watersplitting owing to their suitable band gaps, favourable band alignments, andefficient charge transport properties. However, their practical application hasbeen limited by poor stability in aqueous environments, as they are prone toself-oxidation prior to water oxidation. This instability typically necessitatesthe use of sacrificial agents to scavenge photogenerated holes, therebyrestricting long-term device operation and real-world implementation. Herewe report a metal-encapsulated PbS quantum dot (PbS-QD) solar cell-basedphotoelectrode that simultaneously achieves high photocurrent and long-term operational stability for PEC water splitting without sacrificial agents. Theoptimised PbS-QD-based photoanode delivers a photocurrent density of18.6 mA cm–2 at 1.23 V versus the reversible hydrogen electrode in 1.0 M NaOH,retaining 90% of its initial performance over 24 h. These values are comparableto those reported for chalcogenide-based photoelectrodes operating in thepresence of sacrificial agents.