Electron‐Selective TiO₂ /CVD‐Graphene Layers for Photocorrosion Inhibition in Cu₂O Photocathodes

Abstract

Mitigating photocorrosion in the light absorber material used for photoelectrochemical solar water splitting is a subject of major research. In this work, a systematic investigation is carried out on suppressing the photocorrosion in an electrodeposited Cu2O photocathode using stable protective layers. The photocathode protected with chemical vapor deposited graphene offers significant stability, till 600 s during light chopping chronoamperometry. However, the presence of a few microcracks in the graphene layer cannot offer complete protection, and causes a gradual decay in the photocurrent. The addition of an ultrathin layer (≈10 nm) of amorphous TiO2 on top of the graphene blocks the microcracks, thereby resulting in complete protection to the Cu2O absorber layer. The TiO2/graphene protected Cu2O photocathode generates ‐3 mA cm−2 photocurrent at 0.0 V versus reversible hydrogen electrode under 1 sun in 1 m Na2SO4 electrolyte (pH 7), which is twice that compared to the bare Cu2O electrode. The enhancement in photocurrent can be attributed to the ease of separating the photogenerated charge carriers due to the suitable band alignment and electron selective nature of the protective TiO2/graphene layers.

3D Heterostructured Copper Electrode for Conversion of Carbon Dioxide to Alcohols at Low Overpotentials

“…It is clear from Figure a that the pristine Cu‐f presented only metallic Cu 0 facets, as the XRD pattern exhibited three major peaks at 43°, 51°, and 74° that correspond to (111), (200), and (220) reflections of Cu 0 species . The XRD pattern with Cu anodized also displayed a similar pattern to that of Cu‐f, indicating the oxide layer generated by anodization treatment on Cu‐f (observed in Figure ) was amorphous and therefore not detected by XRD . In contrast, simple annealing treatment with Cu‐f resulted in the formation of CuO and Cu 2 O species, as manifested by peaks at 36°, 39°, and 73° corresponding to CuO (002), (200), and (004); and at 29°, 37°, 42°, and 62° which correspond to (110), (111), (200), and (220) facets of Cu 2 O.…”

A triptych photocatalyst based on the Co-Integration of Ag nanoparticles and carbo-benzene dye into a TiO2 thin film

“…The optical and SEM observations of the samples after the photocatalytic experiments show a better stability of the TiO 2 /Ag/Cbz triptych compared to the TiO 2 /Ag diptych on which the photoactive film is highly degraded ( Figure S17). These observations reveal that the Cbz layer also acts as a protective layer against the TiO 2 photocorrosion [81,82]. This remarkable enhancement of the hydrogen production rate observed with TiO 2 /Ag/Cbz and to a lesser extent with TiO 2 /Ag is attributed to the Ag metal link in the effective vertical Schottky junction between Ag NPs and TiO 2 .…”

A Beehive Inspired Hydrogen Photocatalytic Device Integrating a Carbo‐Benzene Triptych Material for Efficient Solar Photo‐Reduction of Seawater

“…In addition to its specific optoelectronic properties, [ 16,18 ] the Cbz photosensitizer, deposited as a thin layer, thus protects the TiO 2 surface from photo‐corrosion. [ 15,31 ]…”

“…The T‐PC device is shown to exhibit a remarkable stability due to a protecting effect of the thin photosensitive Cbz layer against photo‐corrosion. [ 31 ] The high robustness of the device over at least 5 days under harsh conditions of high pressure (1.8 bar) and salted water, is indeed beyond the state of the art in the field of water splitting.…”