The electrochemical reduction of carbon dioxide and water to fuels using renewable energy is tool to understand the artificial photosynthesis and offers an approach to mitigate the negative impact of anthropogenic carbon dioxide emissions on the planet. The key factor in developing advanced transition metal oxides (TMO) based catalysts is to devise crystals with effective sun light absorption, efficiency and chemical stability. As such, the search for effective, durable, and inexpensive alternatives to photocatalytic material is still an ongoing challenge. WOx and Nb2O5 are interesting materials that has drawn attention due to its high stability, compared to other n-type semiconductors (such as titania), which makes them viable candidates as catalysts in different applications. The key factor is the development of material composition tuning the band gap aims at to produce advanced TMO based catalysts, and, as consequence, to reach an improvement of photon absorption, electron-hole separation and charge transport processes. One interesting alternative is the synthesis of heterostructures, where the main photon absorber is combined with an additional semiconductor to overcome restrictions of wide band gap stable TMOs. With this purpose, hydrothermal synthesis of W18O49/Nb2O5 will be investigated, and their structural, morphological, electrochemical and their use in the photoelectrocatalytic reduction of CO2 into valuable products will be investigated.
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