Insight into the Fabrication and Characterization of Novel Heterojunctions of Fe₂O₃ and V₂O₅ with TiO₂ and Graphene Oxide for Enhanced Photocatalytic Hydrogen Evolution: A Comparison Study

Abstract

Affordable and highly efficient photocatalysts for the hydrogen evolution reaction (HER) are desirable to replace expensive bulk noble-metal use. Currently, many renewable energy studies are ongoing, focusing on photocatalytic water splitting to generate hydrogen. Transition-metal oxide-embedded TiO 2 photocatalysts have emerged as superior catalysts for the HER. Herein, we synthesize two different ternary composites consisting of TiO 2based transition-metal mixed oxides embedded onto graphene oxide (GO) layers which provide superior photocatalytic activity and stability during the HER over conventional expensive catalysts. The Fe 2 O 3 −TiO 2 and V 2 O 5 −TiO 2 particles were well anchored onto GO sheets, which prevents the agglomeration and allows one to explore maximum surface active sites. The synergistic interaction within the composite via heterojunction formation and the enhanced photophysical nature of the composite were well characterized. The optimized composites of GO-embedded Fe−Ti mixed oxide composite (g-FTMO) and V−Ti mixed oxide composite (g-VTMO) having metal−metal molar ratio of 2:1 with a 3.5 % (w/v) catalyst loading exhibit HER rates of 398.18 and 373.01 μmol h −1 under solar radiation. The enhanced photocatalytic activity of optimized g-TMMO 2:1 was attributed to (i) the increased surface area by the incorporation of GO and (ii) the fact that the surface active sites with heterojunctions have lower e − −h + pair recombination and faster electron transfer rates. The results reveal that the prepared composites can be treated as effective photocatalysts during the HER, and the conclusions pave the way for exploration of new similar catalysts for other applications.

A Review on the Progress and Future of TiO2/Graphene Photocatalysts

“…Moreover, GO sheets anchored onto Fe 2 O 3 −TiO 2 and V 2 O 5 −TiO 2 particles exhibited 398.18 and 373.01 µmol h −1 HER rates under solar radiation. The enhanced HER rates were attributed to higher surface areas provided by GO, the lower recombination of photogenerated carriers and faster electron transfer rates [226]. Higher photoelectrochemical activity was also obtained for GO/In 2 S 3 /TiO 2 nanorods used as photocatalysts for photoelectrochemical water splitting [227].…”

Photochemical environment effect on V 2 O 5 ‐Fe 2 O 3 heterostructures for efficient water splitting under visible light

“…The probability of hydrogen generation from water splitting has been determined using various photoelectrodes, such as ZnO, TiO 2 , BiVO 4 , Fe 2 O 3 , V 2 O 5 , and WO 3 1 . V 2 O 5 exhibits remarkable electrochemical and catalytic properties, such as a wide‐ranging optical bandgap, nontoxicity, kinetic behaviors, and high visible‐light absorption; several studies have investigated V 2 O 5 as a catalyst 2 . However, V 2 O 5 structures exhibit great disadvantages of photocorrosion, high recombination rates, and weakening of the photoelectrochemical activity.…”

“…1 V 2 O 5 exhibits remarkable electrochemical and catalytic properties, such as a wide-ranging optical bandgap, nontoxicity, kinetic behaviors, and high visible-light absorption; several studies have investigated V 2 O 5 as a catalyst. 2 However, V 2 O 5 structures exhibit great disadvantages of photocorrosion, high recombination rates, and weakening of the photoelectrochemical activity. Fabricating V 2 O 5 heterostructures with other catalyst materials can extend the long-term stability, reduce electrochemical corrosion, and improve charge separation, thereby enhancing the catalytic performance of V 2 O 5 photoelectrodes.…”