Electron‐Selective TiO2 /CVD‐Graphene Layers for Photocorrosion Inhibition in Cu2O Photocathodes. Issue 17 (30th June 2017)

• Record Type: Journal Article
• Authors: Das, Chandan; Ananthoju, Balakrishna; Dhara, Arpan Kumar; Aslam, Mohammed; Sarkar, Shaibal K.; Balasubramaniam, Kavaipatti R.
• Is Part Of: Advanced materials interfaces. Volume 4:Issue 17(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-06-30
• Subjects: electrodeposition -- electron‐selective layers -- graphene -- photocathodes -- photocorrosion; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201700271
• Languages: English
• ISSNs: 2196-7350

Abstract

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 Cu2 O 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 Cu2 O absorber layer. The TiO2 /graphene protected Cu2 O photocathode generates ‐3 mA cm −2 photocurrent at 0.0 V versus reversible hydrogen electrode under 1 sun in 1m Na2 SO4 electrolyte (pH 7), which is twice that compared to the bare Cu2 O 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. Abstract : Chemical vapor deposited graphene layers are used to prevent the photocorrosion of Cu2 O photocathodes. It is found that the graphene layer cannot offer complete protection to the Cu2 O, due to the presence of microcracks in it. Blocking the cracks with an additional TiO2 (≈10 nm) layer results in better protection against photocorrosion of the Cu2 O, along with enhanced photocurrent.