Assessment of the environmental break-even point for deposit return systems through an LCA analysis of single-use and reusable cups Journal Pre-proof Assessment of the environmental break-even point for deposit return systems through an LCA analysis of single-use and reusable cups
p-Type organic semiconductors are attractive to develop new photo-and photoelectro-catalytic systems, particularly if the conduction band is located at negative redox potentials. An easy synthetic route to produce carbon-doped carbon nitride (C n>3 N 4) with a stable p-type semiconducting character was optimized. The precursors used were melamine and triaminopyrimidine. The p-type C >3 N 4 exhibited a remarkable photoactivity under visible light compared with pristine C 3 N 4 , which is a stable n-type organic semiconductor deeply studied as heterogeneous photocatalyst for many environmental applications. The photoelectrochemical features of the synthesized p-type materials and pristine C 3 N 4 were deeply investigated with chronopotentiometry and cyclic voltammetry, in the dark and under different illumination conditions, and then compared with the photocatalytic activity using 2fluorophenol as substrate and different radiation sources. The p-doping with carbon of C 3 N 4 reduces the band gap, slightly moves the potential of the valence band, and increases the conduction band to more positive potentials, thus precluding the application of these materials when large negative redox potentials are needed.
Recently, the industrial and public interest in hydrogen technologies has strongly risen, since hydrogen is the ideal means for medium to long term energy storage, transport and usage in combination with renewable and green energy supply. Therefore, in a future energy system the production, storage and usage of green hydrogen is a key technology. Hydrogen is and will in future be even more used for industrial production processes as reduction agent or for the production of synthetic hydrocarbons, especially in the chemical industry and refineries. Under certain conditions material based systems for hydrogen storage and compression offer advantages over the classical systems based on gaseous or liquid hydrogen. This includes in particular lower maintenance costs, higher reliability and safety. Hydrogen storage is possible at pressures and temperatures much closer to ambient conditions. Hydrogen compression is possible without any moving parts and only by using waste heat. In this paper, the newest developments of hydrogen carriers for storage and compression are summarized. In addition, an overview of the different research activities in this field are given.
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