Solar Hydrogen Generation from Ambient Humidity Using Functionalized Porous Photoanodes

TitleSolar Hydrogen Generation from Ambient Humidity Using Functionalized Porous Photoanodes
Publication TypeJournal Article
Year of Publication2019
AuthorsG. Zafeiropoulos, H. Johnson, S. Kinge, M.CM van de Sanden, M.N Tsampas
JournalACS Applied Materials & Interfaces
Volume11
Issue44
Pagination41267-41280
Date Published11/2019
Abstract

Solar hydrogen is a promising sustainable energy vector, and steady progress has been made in the development of photoelectrochemical (PEC) cells. Most research in this field has focused on using acidic or alkaline liquid electrolytes for ionic transfer. However, the performance is limited by (i) scattering of light and blocking of catalytic sites by gas bubbles and (ii) mass transport limitations. An attractive alternative to a liquid water feedstock is to use the water vapor present as humidity in ambient air, which has been demonstrated to mitigate the above problems and can expand the geographical range where these devices can be utilized. Here, we show how the functionalization of porous TiO2 and WO3 photoanodes with solid electrolytes—proton conducting Aquivion and Nafion ionomers—enables the capture of water from ambient air and allows subsequent PEC hydrogen production. The optimization strategy of photoanode functionalization was examined through testing the effect of ionomer loading and the ionomer composition. Optimized functionalized photoanodes operating at 60% relative humidity (RH) and Tcell = 30–70 °C were able to recover up to 90% of the performance obtained at 1.23 V versus reverse hydrogen electrode (RHE) when water is introduced in the liquid phase (i.e., conventional PEC operation). Full performance recovery is achieved at a higher applied potential. In addition, long-term experiments have shown remarkable stability at 60% RH for 64 h of cycling (8 h continuous illumination–8 h dark), demonstrating that the concept can be applicable outdoors.

DOI10.1021/acsami.9b12236
Division

MaSF

Department

CEPEA

PID

280b4d854cee1c44960f1b25878e1845

Alternate TitleACS Appl. Mater. Interfaces

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