Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: Poster III

HL 36.54: Poster

Wednesday, March 20, 2024, 18:00–20:30, Poster E

Photoelectrochemical CO₂ reduction with co-catalysts on atomic layer deposited titania protection layers — •Giovanni Postacchini^1,2, Julius Kühne^1,2, and Ian D. Sharp^1,2 — ¹Walter Schottky Institute, Technical University of Munich, Am Coulombwall 4, 85748 Garching, Germany — ²Physics Department, TUM School of Natural Science, Technical University of Munich, Am Coulombwall 4, 85748 Garching, Germany

Light-driven CO₂ reduction is a promising approach to sustainably address increasing anthropogenic CO₂ emissions and meet the ever-increasing energy demand through the production of solar fuels. However, in an electrochemical environment, the semiconductor photoabsorber must be chemically protected against harsh reaction conditions. Atomic layer deposited (ALD) titania is an optimal candidate for photocathode corrosion protection layers thanks to its chemical stability, passivating effect, and optical transparency in the visible/infrared spectrum. Here, different Ag co-catalyst thin layers are deposited on titania-protected photoabsorbers. The photocathodes are characterized by photoelectrochemical (PEC) measurements using a three-electrode setup in a two-compartment cell to assess the photoelectrocatalytic activity and stability under CO₂ reduction conditions. Gas chromatography (GC) measurements allow the quantification of the product gases and determination of the selectivities of photoanodes towards desired reaction products. Further ex-situ AFM, SEM and XPS analyses are conducted to study surface morphology and composition changes and to elucidate possible degradation mechanisms.

Keywords: Photoelectrocatalysis; CO2 reduction; Atomic layer deposition; Titania