Issue 4, 2019

Enhanced charge separation in g-C3N4–BiOI heterostructures for visible light driven photoelectrochemical water splitting

Abstract

Heterojunctions of the low bandgap semiconductor bismuth oxyiodide (BiOI) with bulk multilayered graphitic carbon nitride (g-C3N4) and few layered graphitic carbon nitride sheets (g-C3N4-S) are synthesized and investigated as an active photoanode material for sunlight driven water splitting. HR-TEM and elemental mapping reveals formation of a unique heterostructure between BiOI platelets and the carbon nitride (g-C3N4 and g-C3N4-S) network that consisted of dendritic BiOI nanoplates surrounded by g-C3N4 sheets. The presence of BiOI in g-C3N4-S/BiOI and g-C3N4-S/BiOI nanocomposites extends the visible light absorption profile from 500 nm up to 650 nm. Due to excellent charge separation in g-C3N4/BiOI and g-C3N4-S/BiOI, evident from quenching of the carbon nitride photoluminescence (PL) and a decrease in the PL lifetime, a significant increase in photoelectrochemical performance is observed for both types of g-C3N4–BiOI heterojunctions. In comparison to heterojunctions of bulk g-C3N4 with BiOI, the nanocomposite consisting of few layered sheets of g-C3N4 and BiOI exhibits higher photocurrent density due to lower recombination in few layered sheets. A synergistic trap passivation and charge separation is found to occur in the g-C3N4-S/BiOI nanocomposite heterostructure which results in a higher photocurrent and a lower charge transfer resistance.

Graphical abstract: Enhanced charge separation in g-C3N4–BiOI heterostructures for visible light driven photoelectrochemical water splitting

Supplementary files

Article information

Article type
Paper
Submitted
01 10 2018
Accepted
06 1 2019
First published
07 1 2019
This article is Open Access
Creative Commons BY-NC license

Nanoscale Adv., 2019,1, 1460-1471

Enhanced charge separation in g-C3N4–BiOI heterostructures for visible light driven photoelectrochemical water splitting

K. M. Alam, P. Kumar, P. Kar, U. K. Thakur, S. Zeng, K. Cui and K. Shankar, Nanoscale Adv., 2019, 1, 1460 DOI: 10.1039/C8NA00264A

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