Photocatalytic Water Oxidation by Hematite/Reduced Graphene Oxide Composites

Abstract

The photocatalytic water oxidation activity of hematite (α-Fe2O3) has been greatly enhanced by incorporating hematite nanoparticles on the reduced graphene oxide (rGO) nanosheets. Photoelectrochemical measurement results show that coupling the hematite nanoparticles with the rGO greatly increases the photocurrent and reduces the charge recombination rate. Transient absorption spectroscopy and time-domain terahertz spectroscopy have provided the direct evidence that the photogenerated electrons have transferred as the mobile carriers from α-Fe2O3 to rGO, which enhances the charge separation and suppresses the charge recombination. This work has provided new insight into the mechanism of photocatalysis enhancement by reduced graphene oxide, which has implications in the design of semiconductor/graphene heterojunction photocatalysts.

Novel Composites of α‐Fe2O3 Tetrakaidecahedron and Graphene Oxide as an Effective Photoelectrode with Enhanced Photocurrent Performances

“…Other than the raised current density, the onset potentials of all α-Fe 2 O 3 /GO electrodes are close again and lower than that of pure α-Fe 2 O 3 electrodes, which is in agreement with previous literatures. [ 51 ] The lower onset potentials of three α-Fe 2 O 3 /GO electrodes can be attributed to favorable effect of graphene oxide, which decrease the kinetic energy barrier of charge transfer among the interface of graphene oxide and α-Fe 2 O 3 . [ 34,52 ] The corresponding EIS measurements of the electrodes in Figure 7 a are shown in Figure 7 b.…”

Plasmon-induced photonic and energy-transfer enhancement of solar water splitting by a hematite nanorod array

“…3f), which reflects the general behaviour of charge recombination and lifetime of the charge carriers. t was estimated to be 2.51 s for the hematite on the long-range ordered Au nanohole array pattern under 100 mW cm À 2 of simulated solar light, which was five times that for hematite without the Au nanohole array pattern (0.53 s), indicating the suppressed charge recombination 15,47 . The increase in the recombination lifetime was not due to surface chemistry or bulk trapping states, as the onset potential (in Fig.…”

“…Hematite can be engineered into a nanostructure to reduce the charge-carrier diffusion distance to the electrode/electrolyte interface, and to combat the short carrier lifetime. However, the trade-off is that to satisfy the diffusion length, the structure must be much smaller than the optical absorption depth, limiting the amount of light collected [13][14][15][16][17][18][19] . In fact, no single material can meet all the requirements of an ideal photoelectrode in PECs so far.…”

A New Insight in the Physical and Photoelectrochemical Properties of Molybdenum Disulfide Alpha-Hematite Nanocomposite Films

“…The doping with several metallic ions such as zinc [16], titanium [17] [18], molybdenum [19], aluminum [20], platinum [21], silicon [22] [23] [24], graphene [25] [ 26], and cadmium sulfide [27] Recently, two-dimensional (2D) dichalcogenide material "molybdenum disulfide (MoS 2 )" with bandgap of 1.8 eV has been used as n-and p-types structures for photoelectrochemical studies [5]. The MoS 2 shows stimulating photocatalytic activity due to its bonding, chemical composition, doping, and nanoparticles growth on various film matrices, and has been used for hydrogen production in nanocluster structures [2] [31] [32] [33] [34].…”