Low temperature grown CuBi₂O₄ with flower morphology and its composite with CuO nanosheets for photoelectrochemical water splitting

Abstract

In this work we highlight a peculiar synthesis protocol for the p-type ternary metal oxide system of copper bismuth oxide (CuBi 2 O 4 ), which yields a highly crystalline spherulitic morphology at a low temperature of 78 C. We associate this growth with the hydrogen bonding effects imparted by the ethanol-water cosolvent system used for the synthesis. We present a detailed growth mechanism by evaluating different synthesis conditions systematically. Furthermore we show that upon the use of the non-stoichiometric (excess copper) precursor mixture under the same experimental conditions the growth of spherulitic CuBi 2 O 4 changes the size and type of the spherulites. Interestingly, careful optimization of the nonstoichiometric synthesis presents a complete impediment to the spherulitic growth and produces a composite of nanorods of CuBi 2 O 4 and nanosheets of CuO. This anisotropic nanocomposite shows an order of magnitude higher surface area as compared to spherulitic CuBi 2 O 4 . Since both CuBi 2 O 4 and CuO are visible light absorbing p-type semiconductors, when the synthesized nanocomposite materials are examined as photoelectrochemical (PEC) photocathodes for water splitting, they show a remarkable dependence on the morphology and phase constitution. Almost 13-fold stronger PEC response is observed as the morphology changes from spherulites to nanorods. † Electronic supplementary information (ESI) available. See Scheme 1 Schematic of morphology evolution by precursor ratio control. 3662 | J. Mater. Chem. A, 2014, 2, 3661-3668 This journal is

Electronic structure, photovoltage, and photocatalytic hydrogen evolution with p-CuBi2O4 nanocrystals

“…The XRD pattern matches the JCPDS database (042-0334) and previous reports, respectively. [24][25][26][27][28] No peaks from impurity phases were observed. The crystal size was estimated using Scherrer equation from the diffraction peak widths at half maxima and was found to be about 28 nm.…”

Ionic‐Liquid‐Functionalized Copper Oxide Nanorods for Photocatalytic Splitting of Water

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Directly Photoexcited Oxides for Photoelectrochemical Water Splitting

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