Details

Autor(en) / Beteiligte

• Walczak, Karl A.
• Segev, Gideon
• Larson, David M.
• Beeman, Jeffrey W.
• Houle, Frances A.
• Sharp, Ian D.

Titel

Hybrid Composite Coatings for Durable and Efficient Solar Hydrogen Generation under Diverse Operating Conditions

Ist Teil von

• Advanced energy materials, 2017-07, Vol.7 (13), p.n/a

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2017

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• Safe and practical solar‐driven hydrogen generators must be capable of efficient and stable operation under diurnal cycling with full separation of gaseous H2 and O2 products. In this study, a novel architecture that fulfills all of these requirements is presented. The approach is inherently scalable and provides versatility for operation under diverse electrolyte and lighting conditions. The concept is validated using a 1 cm2 triple‐junction photovoltaic cell with its illuminated photocathode protected by a composite coating comprising an organic encapsulant with an embedded catalytic support. The device is compatible with operation under conditions ranging from 1 m H2SO4 to 1 m KOH, enabling flexibility in selection of semiconductor, electrolyte, membrane, and catalyst. Stable operation at a solar‐to‐hydrogen conversion efficiency of >10% is demonstrated under continuous operation, as well as under diurnal light cycling for at least 4 d, with simulated sunlight. Operational characteristics are validated by extended time outdoor testing. A membrane ensures products are separated, with nonexplosive gas streams generated for both alkaline and acidic systems. Analysis of operational characteristics under different lighting conditions is enabled by comparison of a device model to experimental data. A novel composite coating enables stable and efficient solar hydrogen generation under both basic and alkaline conditions and provides a versatile approach to scalably protect semiconductor light absorbers, integrate catalysts, and manage charge transport. This strategy is verified by demonstration of devices with unbiased solar‐to‐hydrogen conversion efficiencies exceeding 10% with pure gas product streams in both laboratory and outdoor testing environments.