The worldwide availability of safe and clean drinking water constitutes one of the main challenges of our era. Unfortunately, due to progress-related issues such as global warming, population growth and industrial development, the availability and quality of drinking water is expected to deteriorate in the coming years, posing new threats for humans and the environment. In view of these predictions, it becomes increasingly necessary to develop novel, economical and easily scalable methods for water treatment.

Within the context of this thesis, two novel devices for water treatment based on solar energy and Earth-abundant materials are proposed: a photoelectrochemical (PEC) cell using amorphous silicon carbide (a-SiC:H) photoelectrodes and a PV/electrochemical system based on graphite electrodes. In order to evaluate their performance, both systems are tested in the degradation of recalcitrant organic pollutants.

In the photoelectrochemical cell, a-SiC:H was used first as a photoanode (n-i-p structure), and afterwards as a photocathode material (p-i and p-i-n structures).  In both photoelectrode configurations, the degradation of phenol was monitored under different applied bias voltages. Additionally, photoresponse measurements were recorded in order to determine the behaviour of the photoelectrodes in the solution. Unfortunately, none of the photoelectrode configurations were able to develop noticeable photocurrents, resulting in a poor water treatment performance.

With regard to the PV/electrochemical system, the graphite electrodes were first tested under an external power supply. Here, the electrochemical oxidation of phenol was studied in detail under different applied voltages. Additionally, the chemical oxygen demand (COD) was measured in order to identify intermediate compounds in the reaction. Overall, it was found that the optimum voltage for the degradation reaction was 1.6V (80% phenol removal, 59% COD reduction). In addition to this study, the effect of an alternative copper counter-electrode was investigated, and the degradation of an organic dye (methylene blue) was examined. Finally, several PV structures were proposed for the integration with the graphite electrodes. The best overall performance was achieved by two micromorph solar cells connected in series. However, in terms of utilized area, an individual a-Si:H/a-Si:H tandem cell was the most appropriate choice