Cobalt-Prussian blue analogues are remarkable catalysts for the oxygen evolution reaction (water oxidation) under mild conditions such as neutral pH. Although there is extensive reports on literature about the application...

Hydrogen (H2) was one of the first molecules discovered by our society, being the most abundant element in the whole universe. Thus, H2 has gained a lot of attention throughout the years, and it has lots of applications in different areas, especially since it offers ways to decarbonize a lot of sectors, mainly the ones where it has been proved to be very difficult to meaningfully reduce those carbon emissions. Herein, the main aspects of the hydrogen economy and its main applications for energy, transportation and industries are described. These main areas outline how important is H2 for our society highlighting how H2 can make those well-known processes more sustainable and greener. By the end, a brief discussion on these applications with future perspectives is presented.

Hydrogen (H 2 ) is presented as an important alternative for clean energy and raw material in the modern world. However, the environmental benefits are linked to its process of production. Herein, the chemical aspects, advantages/disadvantages, and challenges of the main processes of H 2 production from petroleum to water are described. The fossil fuel (FF)-based methods and the state-of-art strategies are outlined to produce hydrogen from water (electrolysis), wastewater, and seawater. In addition, a discussion based on a color code to classify the cleanliness of hydrogen production is introduced. By the end, a summary of the hydrogen value chain addresses topics related to the financial aspects and perspective for 2050: green hydrogen and zero-emission carbon.

This study reports the preparation of nanostructured cerium-doped titanium dioxide photocatalysts containing different cerium concentrations by a modified sol-gel route involving the use of acetylacetone. The nanocrystalline powders had their structural, morphological, and optical properties characterized by X-ray diffraction, vibrational and Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, Brunauer, Emmett and Teller (BET) surface area analysis, scanning electron microscopy combined with energy dispersive X-ray spectroscopy, total reflection X-ray fluorescence, and diffuse reflectance spectroscopy. Cerium incorporation reduced the bandgap energy of the solids to values that allowed them to absorb visible light. Cerium presence improved the textural properties that are crucial for the catalytic process. The photocatalytic activities were evaluated through photodegradation experiments of methyl orange dye solution. The synthesis with acetylacetone as stabilizer provided nanostructured materials with higher Ce 3+ /Ce 4+ ratio, which enhanced the photocatalytic activity. Smaller quantities of the doped photocatalysts afforded higher degradation rates than the rates reported in the literature.

No abstract