PEDOT nanotube arrays present a better catalytic activity with I−/I3− redox than standard platinized counter electrodes used for dye sensitized solar cells exhibiting thereby a photoconversion efficiency as high as 8.3%. The PEDOT layer introduces an additional series resistance which is compensated by its excellent catalytic performance yielding counter electrodes as good as platinized ones, or even better.

Hydrogen generation by using quantum dot based heterostructures has emerged as a promising strategy to develop artificial photosynthesis devices. In the present study, we sensitize mesoporous TiO 2 electrodes with in-situ deposited PbS/CdS quantum dots (QDs), aiming at harvesting light in both the visible and the near infrared for hydrogen generation. This heterostructure exhibits a remarkable photocurrent of 6 mA·cm -2 leading to 60 ml·cm -2 ·day -1 hydrogen generation. Most importantly, confirmation of the contribution of infrared photons to H 2 generation was provided by the incident-photon-to-current-efficiency (IPCE), and the integrated current was in excellent agreement with that obtained through cyclic voltammetry.The main electronic processes (accumulation, transport and recombination) were identified by impedance spectroscopy, which appears as a simple and reliable methodology to evaluate the limiting factors of these photoelectrodes. Based on this TiO 2 /PbS/CdS heterostructrure, a "quasiartificial leaf" has been developed, which has proven to produce hydrogen under simulated solar illumination at (4.30 ± 0.25) ml·cm -2 ·day -1 .

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