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Molybdenum Disulfide Catalytic Coatings via Atomic Layer Deposition for Solar Hydrogen Production from Copper Gallium Diselenide Photocathodes

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journal contribution
posted on 22.01.2019, 15:51 by Thomas R. Hellstern, David W. Palm, James Carter, Alex D. DeAngelis, Kimberly Horsley, Lothar Weinhardt, Wanli Yang, Monika Blum, Nicolas Gaillard, Clemens Heske, Thomas F. Jaramillo
We demonstrate that applying atomic layer deposition-derived molybdenum disulfide (MoS2) catalytic coatings on copper gallium diselenide (CGSe) thin film absorbers can lead to efficient wide band gap photocathodes for photoelectrochemical hydrogen production. We have prepared a device that is free of precious metals, employing a CGSe absorber and a cadmium sulfide (CdS) buffer layer, a titanium dioxide (TiO2) interfacial layer, and a MoS2 catalytic layer. The resulting MoS2/TiO2/CdS/CGSe photocathode exhibits a photocurrent onset of +0.53 V vs RHE and a saturation photocurrent density of −10 mA cm–2, with stable operation for >5 h in acidic electrolyte. Spectroscopic investigations of this device architecture indicate that overlayer degradation occurs inhomogeneously, ultimately exposing the underlying CGSe absorber.