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Dye-sensitized solar cells (DSSCs) were developed by exploiting the photovoltaic effect to convert solar energy into electrical energy. The photoanode layer thickness significantly affects the semiconductor film’s ability to carry electronic charges, adsorb sensitizing dye molecules, and lower the recombination of photo-excited electrons injected into the semiconductor. This study investigated the dependence of the zinc oxide (ZnO) photoanode thin-film thickness and the film soaking time in N719 dye on the photocurrent–voltage characteristics. The ZnO photoanode was applied to glass using the doctor blade method. The thickness was varied by changing the scotch tape layers. The ZnO-based DSSC attained an efficiency of 2.77% with three-layered photoanodes soaked in the dye for three hours, compared to a maximum efficiency of 0.68% that was achieved with three cycles using the dip-coating method in other research. The layer thickness of the ZnO photoanode and its optimal adsorption time for the dye are important parameters that determine the efficiency of the DSSC. Therefore, this work provides important insights to further improve the performance of DSSCs.

We studied the operation of a twin-cell electrochemical filter for removing carbon monoxide (CO) from reformate hydrogen by periodically adsorbing and then electrochemically oxidizing CO on the electrode. During the adsorption step, we studied the effects of feed CO concentration, flow rate, electrode catalyst loading, type of feeder gas, and temperature on CO breakthrough. We then applied a fixed bed adsorber model to show that the breakthrough time could be accurately correlated to the adsorption-step operating parameters. Since the oxidation step was found to be much faster than that for CO breakthrough, adsorption time should dictate switching time. This insight was used to predict steady-state filter performance, and the prediction was validated for an electrochemical filter operated with CO contaminated hydrogen to decrease the CO concentration from 10, 000 to 10 ppm. The model was also used to explore the employability of an electrochemical filter over a range of operating conditions by considering the comparative electrode area of a filter with that of a fuel cell. � The Author(s) 2015.