TY - JOUR
T1 - Impact of NiCo2O4/SrTiO3 p–n Heterojunctions on the Interface of Photoelectrochemical Water Oxidation
AU - Wang, Hongxia
AU - Wang, Yan
AU - Lin, Yumei
AU - Huang, Xiaochun
AU - García-Tecedor, Miguel
AU - de la Peña O'Shea, Víctor A
AU - Murrill, Connor
AU - Lazarov, Vlado K
AU - Oropeza, Freddy E
AU - Zhang, Kelvin H L
N1 - © 2023 American Chemical Society. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details
PY - 2023/6/14
Y1 - 2023/6/14
N2 - Forming semiconductor heterojunctions is a promising strategy to boost the efficiency of solar-driven photoelectrochemical (PEC) water splitting by accelerating the separation and transport of photogenerated charge carriers via an interfacial electric field. However, there is limited research considering the influence of electrolytes on the band alignment of the heterojunction under PEC conditions. In this work, we use a single crystal NiCo
2O
4/SrTiO
3 (NCO/STO) heterojunction with atomic-precision controlled thickness as a model photoelectrode to study the band structure modulations upon getting in contact with the electrolyte and the correlation with the PEC activity. It is found that the band alignment can be tuned by the control of p-n heterojunction film thickness and regulated by the water redox potential (
E
redox). When the Fermi level (
E
F) of the heterojunction is higher/lower than the
E
redox, the band bending at the NCO/STO-electrolyte interface will increase/decrease after contacting with the electrolyte. However, when the band bending width of the NCO layer is thinner than its thickness, the electrolyte will not influence the band alignment at the NCO/STO interface. In addition, PEC characterization results show that the 1 nm NCO/STO heterojunction photoanode exhibits superior water-splitting performance, owing to the optimum band structure of the p-n heterojunction and the shorter charge transfer distance.
AB - Forming semiconductor heterojunctions is a promising strategy to boost the efficiency of solar-driven photoelectrochemical (PEC) water splitting by accelerating the separation and transport of photogenerated charge carriers via an interfacial electric field. However, there is limited research considering the influence of electrolytes on the band alignment of the heterojunction under PEC conditions. In this work, we use a single crystal NiCo
2O
4/SrTiO
3 (NCO/STO) heterojunction with atomic-precision controlled thickness as a model photoelectrode to study the band structure modulations upon getting in contact with the electrolyte and the correlation with the PEC activity. It is found that the band alignment can be tuned by the control of p-n heterojunction film thickness and regulated by the water redox potential (
E
redox). When the Fermi level (
E
F) of the heterojunction is higher/lower than the
E
redox, the band bending at the NCO/STO-electrolyte interface will increase/decrease after contacting with the electrolyte. However, when the band bending width of the NCO layer is thinner than its thickness, the electrolyte will not influence the band alignment at the NCO/STO interface. In addition, PEC characterization results show that the 1 nm NCO/STO heterojunction photoanode exhibits superior water-splitting performance, owing to the optimum band structure of the p-n heterojunction and the shorter charge transfer distance.
U2 - 10.1021/acsami.3c02783
DO - 10.1021/acsami.3c02783
M3 - Article
C2 - 37253189
SN - 1944-8244
VL - 15
SP - 28739
EP - 28746
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
IS - 23
ER -