Effect of heterojunction structures on photoelectrochemical properties of ZnTe-based photocathodes for water reduction

Tooru Tanaka; Ryusuke Tsutsumi; Tomohiro Yoshinaga; Takaki Sonoyama; Katsuhiko Saito; Qixin Guo; Shigeru Ikeda

doi:10.1039/d2ra06301h

Effect of heterojunction structures on photoelectrochemical properties of ZnTe-based photocathodes for water reduction

RSC Adv. 2022 Dec 22;13(1):575-580. doi: 10.1039/d2ra06301h. eCollection 2022 Dec 19.

Authors

Tooru Tanaka¹, Ryusuke Tsutsumi¹, Tomohiro Yoshinaga¹, Takaki Sonoyama¹, Katsuhiko Saito¹, Qixin Guo¹, Shigeru Ikeda²

Affiliations

¹ Department of Electrical and Electronic Engineering, Saga University Saga 840-8502 Japan ttanaka@cc.saga-u.ac.jp.
² Department of Chemistry, Konan University Kobe Hyogo 658-8501 Japan.

Abstract

Photoelectrochemical (PEC) properties of ZnTe-based photocathodes with various structures were investigated to clarify the effective structure for the water reduction reaction. Samples with n-ZnO/ZnTe/p-ZnTe and n-ZnS/ZnTe/p-ZnTe heterostructures showed superior PCE properties to the samples without a heterojunction. In particular, the n-ZnS/ZnTe/p-ZnTe sample exhibited a large photocurrent even at a low applied potential in an electrolyte containing Eu³⁺ ion as an electron scavenger. Appreciable H₂ evolution with a constant rate (approximately 87 μmol cm^-2 h^-1) was also observed over the sample loaded with Pt deposits under visible-light irradiation (>420 nm): faradaic efficiency of almost 100% was obtained, indicating no unfavorable side reaction occurred in the sample.