The Role of Catalyst Adhesion in ALD-TiO₂ Protection of Water Splitting Silicon Anodes

Abstract

Atomic layer deposited titanium dioxide (ALD-TiO2) has emerged as an effective protection layer for highly efficient semiconductor anodes which are normally unstable under the potential and pH conditions used to oxidize water in a photoelectrochemical cell. The failure modes of silicon anodes coated with an Ir/IrO x oxygen evolution catalyst layer are investigated, and poor catalyst/substrate adhesion is found to be a key factor in failed anodes. Quantitative measurements of interfacial adhesion energy show that the addition of TiO2 significantly improves reliability of anodes, yielding an adhesion energy of 6.02 ± 0.5 J/m2, more than double the adhesion energy measured in the absence of an ALD-TiO2 protection layer. These results indicate the importance of catalyst adhesion to an interposed protection layer in promoting operational stability of high efficiency semiconducting anodes during solar-driven water splitting.

Recent Advances in Materials Design Using Atomic Layer Deposition for Energy Applications

“…Reproduced with permission. [ 123 ] Copyright 2018, American Chemical Society. (h) Nyquist plots of pristine Fe 2 O 3 and ALD‐TiO 2 coated Fe 2 O 3.…”

Atomic Layer Deposition for the Photoelectrochemical Applications

“…It is shown that ALD deposited TiO 2 significantly improves surface adhesion of the IrO x oxygen evolution catalyst compared to the dispersion on native SiO 2 . [ 119 ]…”

Enhancing photocatalytic performance and solar absorption by schottky nanodiodes heterojunctions in mechanically resilient palladium coated TiO2/Si nanopillars by atomic layer deposition

“…11,12 However, as photoanode, bare Si suffers from fast degradation and corrosion in aqueous environments, which dramatically limits its operation time 13 Several strategies based on the introduction of protective coatings to hinder surface passivation have been proposed to extend the lifetime of Si based photoanodes 14,15 Additional studies have shown the advantages of TiO2 or ZnO coatings on the performance of Si-NPls, [16][17][18] due to their optical tunability, 6 mechanical reinforcement, 10,19 and high photoactive performance. 6,10 Recently, photoactive junctions of precious metals and semiconducting materials have shown enhanced carrier transport capabilities of photogenerated electrons which could provide a more efficient catalytic performance for water splitting [20][21][22][23][24][25][26] . In principle, photoactive junctions between precious metals and semiconducting oxides are more efficient when contact areas are maximized.…”