Construction of α-Fe2O3-NPs@AgVO3-NRs Z-scheme heterojunction: An efficient photo(electro)catalyst for Cr(VI) reduction and oxygen evolution reactions under visible-light

Abstract

In this work, we have prepared a mesoporous α-Fe 2 O 3 -NPs@AgVO 3 -NRs (0D/1D) Z-scheme semiconductor photocatalytic system for energy production and environmental remediation applications. The AgVO 3 -nanorods were prepared by the co-precipitation method, whereas α-Fe 2 O 3 -NPs were prepared via the hydrothermal method , and a α-Fe 2 O 3 @AgVO 3 heterojunction was synthesized through the wet-impregnation method. The porous structure of α-Fe 2 O 3 @AgVO 3 nanocomposite provides more surface-active sites for oxygen evolution reaction (OER) and facilitates mass transfer at the contact between α-Fe 2 O 3 -NPs and AgVO 3 -NRs. UV-DRS and photoluminescence showed that the α-Fe 2 O 3 @AgVO 3 catalyst exhibits excellent visible light trapping capability, broadening the spectral absorption range and extending the life of photoinduced carriers. The synergetic effect of an α-Fe 2 O 3 -NPs@AgVO 3 -NRs core-shell-like heterojunction increases the specific surface area , light harvesting capability, and excellent charge separation. As a result, the optimal α-Fe 2 O 3 @AgVO 3 photocatalyst displayed excellent photoreduction efficiency of 94.27% towards Cr(VI) within 20 min. Also, α-Fe 2 O 3 -NPs@AgVO 3 -NRs exhibited an OER overpotential of 1.05 mV (vs RHE) and photocurrent density of around 6.2 mA cm –2 in 0.5 M KOH under AM 1.5 G illumination. The Z-scheme heterojunction formation showed exceptional photogenerated charge carrier migration/separation for the photo-redox reactions. The photo(electro)catalytic mechanism was explained for α-Fe 2 O 3 -NPs@AgVO 3 -NRs nanocomposite concerning the radical trapping experiments and the electrochemical Mott-Schottky results. Thus, this work provides a feasible strategy for synthesizing binary synergistic catalytic systems for photo(electro)chemical applications.

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