摘要： Solar applications in the treatment of waste water fields were limited by the fact that the photocatalytic efficiency of photoreactors, and specifically the photocatalyst used, was less than one percent. Here we report a study investigating the catalysts based on Zn1?xMxO compounds for different [M]/[Zn] atomic ratios. M elements: Na, K, Li, Fe, V, Co, Mg, Mn, Ca, In, Al, P, Ce, were selected. All these catalysts were synthesized by sol-gel process. The morphological, compositional structural and optical properties of the obtained samples were studied by SEM, EDS, XRD and UV-Vis-NIR DRS. To evaluate photocatalytic efficiency, experiments were conducted under controlled irradiation, i.e. ultraviolet, visible or simulated sunlight. The responses showed that when the catalysts were synthesized to capture photons in the visible range, these photons were inefficient at generating radicals. These inefficiencies reflect the fact that the catalysts work poorly over the solar spectral range. Although some element families (alkaline earth metals) offer promising results, a huge effort was still needed to make catalysts efficient enough for solar applications.