Solution combustion synthesis (SCS) is shown to be versatile for the rapid-one-pot synthesis of three compounds and four polymorphs in the Cu−V−O ternary family: α-CuV 2 O 6 , αand β-Cu 2 V 2 O 7 , and γ-Cu 3 V 2 O 8. These compounds feature copper/vanadium stoichiometric ratios ranging from 1:1 to 3:1; their structural, electronic, optoelectronic, and photoelectrochemical attributes were comprehensively characterized by a combination of theoretical and experimental techniques. The main contribution of the present study is the demonstration that a range of stoichiometries in this compound family can be derived simply by tuning the precursor mole ratio in the SCS procedure. The Cu−V−O family of samples, derived by SCS, is shown to exemplify the strong effect of compound stoichiometry on the optoelectronic and photoelectrochemical properties. Overall, α-CuV 2 O 6 showed the best performance, rooted in the direct nature of the optical transition in this material. Finally, SCS is very timeefficient and the various compositions can be obtained in a matter of minutes, as opposed to hours or even days in classical solution-based or ceramic synthesis routes.
This
study addresses a perennial problem in the synthesis of copper
vanadates, namely, that of phase purity. A time-efficient solution
combustion synthesis (SCS) was employed for obtaining α-CuV2O6 in a polycrystalline powder form in a matter
of minutes. Admixture of the final product with α-Cu2V2O7 or V2O5 was avoided
by a combination of careful pH control of the SCS precursor mixture
and by a postsynthesis NaOH wash. The phase purity of the resultant
product was demonstrated by Rietveld refinement of the X-ray diffraction
data, energy-dispersive X-ray analyses, and laser Raman spectroscopy.
Photoelectrochemical (PEC) measurements showed the material to be
an n-type semiconductor. Possible applicability of α-CuV2O6 in PEC devices designed for solar water splitting
hinges on a comprehensive study of its structural, optical, magnetic,
and optoelectronic attributes; this was done by a combination of theory
and experiment. Intensity-modulated photocurrent spectroscopy on thin
film samples permitted an assessment of the balance between charge
transfer and surface recombination, underlining that the charge separation
efficiency determined the photocurrent magnitude. Finally, experiments
on the PEC stability of this material on prolonged (∼4 h) irradiation
revealed self-healing behavior induced by incipient photocorrosion
product layer formation on the oxide semiconductor surface.
A solid‐state perspective is offered for a discussion of silver‐based ternary and quaternary oxide semiconductors for applications related to solar fuels photogeneration and environmental remediation. The rather unique d10 electron configuration in these compounds is shown to impart interesting effects on their optoelectronic properties, and in turn, the photocatalytic activity of these compounds. This Minireview focuses on the structural aspects, electronic band structures, synthetic advances, and finally photoelectrochemical and photocatalytic applications of 32 compounds within the two oxide families, of the generic formula: AgxByOz or AgxByCnOz, where B and C are metals or non‐metals other than silver.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.