###### Abstract  
The development of new materials and processes, able to complete the approaching energetic transition challenge, aiming to produce, convert, harvest, transport, and store clean energy [1, 2, 3], is strictly related to global environmental issues. Indeed, the limited reserves of fossil fuels, together with their high environmental impact on greenhouse gas emissions and the growth of the global energy demand, have raised the ambitious goal to produce efficient materials for energy-related fields, able at the same time to respond to sustainable and environmentally friendly principles [4, 5]. The possibility to undertake a virtuous circuit that is able to give new life to waste products is also a possibility that well fits these objectives [6, 7]. In order to reach these targets, multi-disciplinary expertise is required and encouraged. In this view, in this Special Issue, novel, advanced and improved materials were fully investigated and applied to improve energy systems, sensing devices and waste vaporization for fuel production. [PERSON] et al. [8] employed a promising ionic liquid as an advanced heat transfer fluid in solar thermal energy applications. Thanks to their high heat capacity, low melting point and relatively high density in the typical operating conditions of solar thermal energy systems, ionic liquid can be used in this field, but needs to be opportunely selected. Authors investigated the thermal stability and corrosion effects of these compounds, developing a promising method for their selection with a suitable lifetime able to meet the durability requirements of commercial and industrial solar thermal applications [8]. A composite material based on silicone vapor-permeable foam filled with lithium chloride salt was investigated for low-temperature heat storage applications by [PERSON] et al. [9]. Thermal energy storage is regarded an efficient and effective means to store solar energy when it is available in excess. In this process, heat is transferred to the material that, due to the dehydration reaction, is stored as long as the salt is in the dehydrated form. When heat is required, water is made accessible to the salt, reversible hydration takes place and heat is released, making the heat discharge available and controllable on demand. Lithium chloride salt was used for this purpose, but, being known for its deliquescent effect, it was incorporated in a composite matrix, characterized, and tested under hydration/dehydration cycles. The results showed an effective embedding of the material, which limited the salt release when overhydrated, thus making it a competitive candidate in the related application field [9]. A light harvesting system was presented by [PERSON] [10]. Silicon nanowires were coated with a graphene layer and plasmonic nanoparticles were distributed on the top surface of the silicon substrate layer to realize a solar cell. The proposed structure was used for efficient light harvesting in the visible and near-infrared regions. The performance of the solar cell was tested for different nanoparticle materials and dimensions, as well as for different solar cell structures, reporting improved results compared to similar reported systems [10]. [PERSON] et al. [11] presented a metal oxide sensor based on zinc oxide for possible use in the monitoring of low concentrations of volatile organic compounds, that are generally released during the phenomenon of food degradation. In particular, the device was able to detect the target volatile, hexanal, with minimum interference from all the others. In this way the material was proved to function as a selective gas sensor, giving an important indication of the quality and conservation of meat [11]. Similarly, [PERSON] et al. [12] used a nanostructured material based on tin oxide to develop low cost and real-time resistive sensors useful in the monitoring of the fermentation process and storage of many foods and beverages.