Issue 18, 2023

Overcoming residual carbon-induced recombination in water-oxidation catalysis: combining a superior catalyst with low-carbon-content atomic layer deposition of SnO2 for improved catalysis

Abstract

Previously an all earth-abundant dye-sensitized photoelectrochemical cell, composed of nanostructured SnO2 coated in perylene diimide dye (N,N′-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) plus photoelectrochemically deposited cobalt oxide (CoOx) catalyst, was shown to photoelectrochemically oxidize water. However, in that earlier work and device the addition of a known water-oxidation catalyst (WOCatalyst), CoOx, was found to reduce photocurrents, an effect that we termed an “anti-catalyst” effect to emphasize its unexpected, opposite-from-desired nature. The cause of the anti-catalyst effect was discovered to be residual carbon in the nanostructured SnO2 scaffolding necessary to increase surface area and photocurrents, hence actually residual-C-containing SnOxCy scaffolding. Herein, we examine two approaches to overcome this undesired anti-catalyst effect. First, we demonstrate photocurrent improvement with the addition of a more active, state-of-the-art, amorphous Li-IrOx, WOCatalyst. Second, we employ more phase-pure, planar SnO2 prepared by atomic layer deposition (ALD) and quantitatively compare, by optical absorption and double-layer capacitance measurements, the performance of ALD-SnO2vs. the nano-SnOxCy made in house following a literature recipe. The more phase-pure ALD-SnO2 yielded higher photocurrents based on either per dye or per electrochemically active surface area basis. Finally, in a third approach we combine both strategies for overcoming the anti-catalyst effect, specifically we use the best-in-class Li-IrOx catalyst and ALD-SnO2 to generate a best-performing device to date for this system. The results offer three successful approaches to overcome the anti-catalyst effect caused by residual-carbon-based recombination.

Graphical abstract: Overcoming residual carbon-induced recombination in water-oxidation catalysis: combining a superior catalyst with low-carbon-content atomic layer deposition of SnO2 for improved catalysis

Supplementary files

Article information

Article type
Paper
Submitted
20 Feb 2023
Accepted
28 Jul 2023
First published
15 Aug 2023
This article is Open Access
Creative Commons BY license

Sustainable Energy Fuels, 2023,7, 4567-4579

Overcoming residual carbon-induced recombination in water-oxidation catalysis: combining a superior catalyst with low-carbon-content atomic layer deposition of SnO2 for improved catalysis

C. F. Jewell, A. Subramanian, W. Lee, C. Nam and R. G. Finke, Sustainable Energy Fuels, 2023, 7, 4567 DOI: 10.1039/D3SE00222E

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