For thousands of years humanity has used substances extracted from plants, insects, soil and rocks to give color to fabrics, ceramics and other products. However, the use of these natural dyes declined with the invention of synthetic dyes in the mid-nineteenth century. Nowadays, synthetic dyes are used in a variety of industries, from textiles to cosmetics, and both production use of these substances can lead to environmental problems if they are not properly degraded or removed from industrial effluents.

Vitiligo is a disease characterized by loss of skin pigmentation due to the death of cells called melanocytes, responsible for melanin production. This disease afflicts up to 1% of the world population and current treatments are not effective and exhibit several side effects.

According to the most accepted theory, the disease results from an autoimmune reaction. It is known that one of the proteins involved in melanin synthesis, called TyRP-1, also functions as a melanocyte differentiation antigen, marking the melanocytes to be attacked by the immune system. Therefore, a possible strategy to thwart the progression of the disease is to prevent the production of TyRP-1.

The growing understanding that the rise in average temperature of the planet is caused by human action has, in recent years, intensified the search for clean, renewable and cheap energy sources. One alternative source are the second generation biofuels produced from agricultural waste, such as sugar cane straw and bagasse, which are mainly composed of cellulose. The production of second generation ethanol, for example, breaks down this cellulose into simpler sugars with the use of several enzymes, followed by fermentation into ethanol.

In agriculture, several of the nutrients needed for the growth and development of plants are supplied or supplemented by fertilizers. Some nutrients, such as phosphorus ($ \rm P $) and potassium ($ \rm K $), are needed in large quantities, but obtained from limited mineral sources. Others - such as manganese ($ \rm Mn $), copper ($ \rm Cu $) or zinc ($ \rm Zn $) - are only needed in small quantities and their excessive application can be toxic to plants or to important microorganisms present in the soil.

Hydrogen gas ($\rm H_2 $) is one of the alternatives to fossil fuels since its combustion has as final product only water vapor. A promising way to produce hydrogen is from the so-called biogas: methane ($\rm CH_4 $) and carbon dioxide ($ \rm CO_2 $) originated from the fermentation of organic matter in anaerobic environments, such as landfills.

One possible process for this transformation is the dry reforming of methane (DRM), where $\rm CO_2 $ and $\rm CH_4$ in the biogas react (in the presence of a catalyst) yielding a mixture of $\rm H_2$ and carbon monoxide ($\rm CO$) known as the synthesis gas.

Catalysts are substances that promote and accelerate chemical reactions without being consumed during the process and are widely used in industrial processes to produce various chemicals.

Catalysts based on copper nanoparticles dispersed in an oxide support benefit various reactions, such as the synthesis of methanol, the alcohol dehydrogenation, or the water gas shift (WGS) reaction which is one of the main processes for hydrogen production on an industrial scale. In this reaction, carbon monoxide reacts with water to produce carbon dioxide $ \rm CO_2 $ and hydrogen gas $\rm H_2$.

Actinides are a series of chemical elements that form the basis of nuclear fission technology, finding applications in strategic areas such as power generation, space exploration, diagnostics and medical treatments, and also in some special glass. Thorium (Th) and Uranium (U) are the most abundant actinides in the Earth's crust.

The production of chemical compounds from simpler organic molecules is of great importance for various industrial processes. It is based on the bonding between carbons of the precursor organic compounds, aided by catalysts (typically transition metals). These reactions make it possible to obtain natural and synthetic substances for the development of new materials, such as polymers and pharmaceuticals.

Semiconductors are a class of materials essential for the electronics industry. They have intermediate properties between conductors and insulators, which can be modified by doping with different chemical elements or by the application of electric fields or light. Black phosphorus is a stable form of phosphorus whose crystalline structure is composed by stacking two-dimensional, one atom thick, thin layers. This material has immense potential to be used in electronic devices at the nanoscale due to its semiconductor properties, which can be adjusted by the number of atomic layers according to the need.

The hydrogen gas ($\rm H_2$) is one of the best alternatives to fossil fuels because its combustion has as final product only water vapor. However, several technological challenges still need to be overcome in order to make it economically viable. One way to produce hydrogen is by breaking down water molecules $\rm H_2O$, with formation of $\rm H_2$ molecules. The main reaction in this process is the Hydrogen Evolution Reaction (HER) in which the protons in an acid medium are reduced and form hydrogen gas by electrons passed through catalysts.