CdS-Decorated Porous Anodic SnOx Photoanodes with Enhanced Performance under Visible Light

Abstract

Electrochemically generated nanoporous tin oxide films have already been studied as photoanodes in photoelectrochemical water splitting systems. However, up to now, the most significant drawback of such materials was their relatively wide band gap (ca. 3.0 eV), which limits their effective performance in the UV light range. Therefore, here, we present for the first time an effective strategy for sensitization of porous anodic SnOx films with another narrow band gap semiconductor. Nanoporous tin oxide layers were obtained by simple one-step anodic oxidation of metallic Sn in 1 M NaOH followed by further surface decoration with CdS by the successive ionic layer adsorption and reaction (SILAR) method. It was found that the nanoporous morphology of as-anodized SnOx is still preserved after CdS deposition. Such SnOx/CdS photoanodes exhibited enhanced photoelectrochemical activity in the visible range compared to unmodified SnOx. However, the thermal treatment at 200 °C before the SILAR process was found to be a key factor responsible for the optimal photoresponse of the material.

Atomic layer deposition of SnO2 using hydrogen peroxide improves the efficiency and stability of perovskite solar cells

“…The spin–orbit splitting of about 8.4 eV and binding energies indicate that the oxidation state of tin is close to being tetravalent. 32 The slightly higher binding energies observed for the H 2 O 2 -derived SnO 2 implies that the oxidation state of tin in the H 2 O 2 -derived SnO 2 is relatively higher than that in the H 2 O-derived one, 33–36 which might be due to the stronger oxidizing characteristics of H 2 O 2 . Oxygen 1s XPS spectra in Fig.…”

Electrochemistry at Krakowian research institutions

“…The obtained anodic alumina oxide (AAO) templates are widely used for the fabrication of nanostructured electrodes of metals [163], alloys [164,165], and polymers [166,167]. Produced nanostructures and oxides can be applied in catalysis [168], photoelectrochemistry, and photocatalysis [169][170][171][172][173][174], as H 2 O 2 sensors [175][176][177][178], semiconductors [158,179], and in biomedical applications [180][181][182][183][184]. The research group worked also on the synthesis of Au [185,186] and Au-Ag [187] for electrochemical epinephrine sensing.…”

Enhanced Photoelectrochemical Activity of Anodically Generated FTO/Nanoporous SnOx Decorated with BiVO4

“…On the other hand, regarding properties of the crystalline SnO 2 ( E g ∼ 3.8 eV), it is widely known that this semiconductor is unable to effectively absorb irradiation from the visible region and suffers from limited charge carriers transport that affects the effectiveness of the oxidation performance . Within this context, to address the above-mentioned drawbacks, many research efforts have been devoted to coupling of tin oxide-based materials with narrower-band gap semiconductors to enhance the range of the absorbed light and catalytic activity for the water oxidation process. , According to this, sensitization of tin oxide-based nanomaterials with a BiVO 4 seems to be an accurate strategy, since bismuth vanadate is an efficient visible light absorbing semiconductor ( E g ∼ 2.4 eV), with a desired band edges positions vs pure SnO 2 that facilitate efficient charge carriers separation and transport. It should be mentioned that the use of the SnO 2 /BiVO 4 photoanode for photoelectrochemical water splitting systems has already been described in the literature, indicating a significant improvement when compared to particular semiconductors. − However, none of the studied heterostructures have been related to anodically fabricated nanoporous tin oxide.…”