title: Cu2O Photocathode for Low Bias Photoelectrochemical Water Splitting Enabled by NiFe-Layered Double Hydroxide Co-Catalyst.
abstract: Layered double hydroxides (LDHs) are bimetallic hydroxides that currently attract considerable attention as co-catalysts in photoelectrochemical (PEC) systems in view of water splitting under solar light. A wide spectrum of LDHs can be easily prepared on demand by tuning their chemical composition and structural morphology. We describe here the electrochemical growth of NiFe-LDH overlayers on Cu2O electrodes and study their PEC behavior. By using the modified Cu2O/NiFe-LDH electrodes we observe a remarkable seven-fold increase of the photocurrent intensity under an applied voltage as low as -0.2 V vs Ag/AgCl. The origin of such a pronounced effect is the improved electron transfer towards the electrolyte brought by the NiFe-LDH overlayer due to an appropriate energy level alignment. Long-term photostability tests reveal that Cu2O/NiFe-LDH photocathodes show no photocurrent loss after 40 hours of operation under light at -0.2 V vs Ag/AgCl low bias condition. These improved performances make Cu2O/NiFe-LDH a suitable photocathode material for low voltage H2 production. Indeed, after 8 hours of H2 production under -0.2 V vs Ag/AgCl the PEC cell delivers a 78% faradaic efficiency. This unprecedented use of Cu2O/NiFe-LDH as an efficient photocathode opens new perspectives in view of low biasd or self-biased PEC water splitting under sunlight illumination.
authors.affiliation: School of Materials Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Huan
authors.initials: H
authors.lastname: Qi
authors.affiliation: Interdisciplinary Graduate School, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wolfe
authors.affiliation: School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.|CNRS, UMR 8232, Institut Parisien de Chimie Moléculaire, Paris, France.|Sorbonne Universités, UPMC Univ Paris 06, UMR 8232, Institut Parisien de Chimie Moléculaire, F-75005, Paris, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Fichou
authors.affiliation: School of Materials Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen