Corrosion behavior of SiC coated HX with MoSi2 interlayer to be utilized in iodine-sulfur cycle for hydrogen production.

In this era, renewable energy technologies are suitable to meet the challenges of fossil fuel depletion and global warming. Thus, hydrogen is gaining attention as an alternative clean energy carrier that can be produced from various methods, one of them is the iodine-sulfur (I-S) cycle which is a thermochemical process. The I-S cycle requires a material that can withstand an extremely corrosive environment at high temperatures. Immersion tests were conducted on bare superalloy Hastelloy X (HX), MoSi2, and SiC-MoSi2 coated HX, deposited in physical vapor deposition (PVD) to evaluate their corrosion resistance. Bare HX exhibited a high corrosion rate of 208.1 mm yr-1 when exposed to 98 wt% sulfuric acid at 300 °C. In contrast, HX with MoSi2 coating showed a much lower corrosion rate of 23.5 mm yr-1, and HX with SiC-MoSi2 coating demonstrated the lowest corrosion rate at 6.5 mm yr-1 under the same conditions. The coated samples were analyzed via FESEM before and after corrosion testing. The FESEM images reveal the formation of coalescent particles on the surface of the coating. The elemental analysis illustrates an increased concentration of silicon and oxygen in the corroded samples. Elemental mapping of these samples show a uniform distribution of elements over the sample. These findings contribute not only to materials science understanding but also to practical applications in hydrogen production via the I-S cycle, where corrosion-resistant materials are critical.

Fabrication of cellulose paper-based counter electrodes for flexible dye-sensitized solar cells.

Here, we introduce the synthesis and deposition of organic/inorganic composite ink on cellulose paper using a rapid ultrasonic spray deposition approach that can be incorporated as a counter electrode (CE) in flexible dye-sensitized solar cells (FDSSCs). The composite ink comprised a copper indium sulfide (CuInS2) nanostructure ink and dispersion of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) in water. Fabricated counter electrodes are biodegradable, environment-friendly, flexible, and economical and meet the requirements for sustainable green energy. To evaluate the catalytic activities and power conversion efficiencies of DSSCs, the produced CuInS2/PEDOT:PSS composite ink-based CEs were compared with PEDOT:PSS counter electrodes. Cyclic voltammetry studies found that CuInS2/PEDOT:PSS had a greater cathodic charge transfer current density (Jc) (-1.23 mA cm-2). Moreover, it was found that the potential separation values are small, which indicate a stronger catalytic activity than PEDOT:PSS counter electrodes. The observed exchange current density (J0) was 3.98 mA cm-2, while the limiting current density (Jlim) increased to 45.7 mA cm-2, indicating a fast redox diffusion rate of the CuInS2/PEDOT:PSS CE. The photovoltaic performances of CuInS2/PEDOT:PSS and PEDOT: PSS-based DSSC's were measured and determined to be 5.66% and 4.41%, respectively, while the performance of CuInS2/PEDOT:PSS FDSSC composed of cellulose paper was 1.06%.