A novel photoanode based on Thorium oxide (ThO<inf>2</inf>) incorporated with graphitic Carbon nitride (g-C<inf>3</inf>N<inf>4</inf>) for Photoelectrochemical water splitting

In this study, a new insight into the doping engineering with nuclear fuel (ThO2) was performed and applied in photoelectrochemical (PEC) water splitting. The successfully synthesized g-C3N4/ThO2 (~5.8%) via thermal treatment and g-C3N4 polymerization (precursor: Urea, 30 min; 520 ˚C) manifested a remarkable and superior photocatalytic activity. The photocurrent density achieved for g-C3N4/ThO2 was 9.71 μcm−2 at 1.23 V vs. Ag/AgCl under simulated light (100 mW/cm2) that is more than twice compared with the un-doped g-C3N4 (~4.23 μA cm−2). The introduction of Thorium Nitrate during g-C3N4 polymerization altered the chemical bonding, structure, and morphology, with the improved PEC stability of the photoanode. Besides, doping with ThO2 increased the intensity of triazine and C-N bond in the g-C3N4 network, as observed by FT-IR analysis. The unique “hollow cylindrical” architecture also increased the surface area, light absorption, as well as the catalytic sites. The enhanced separation of photo-generated electron–hole pairs reduced the carrier recombination that was obviously probed via Photoluminescence spectra. Therefore, due to the photostability and the good performance, the g-C3N4/ThO2 composite can be envisioned as a potential candidate in the field of photocatalysis and prospectively be applied in PEC solar water splitting

Electrodeposition of BiVO<inf>4</inf> with needle-like flower architecture for high performance photoelectrochemical splitting of water

Photoelectrochemical (PEC) water splitting is a green and sustainable approach capable of driving mass hydrogen production in the future. To realize this vision, development of a well-performing photoelectrode is highly demanded. In this comprehensive study, electrodeposition technique was applied for fabricating BiVO4 films by regulating the deposition time from 1 min until 9 min. Interestingly, the morphology, crystallinity, chemical structure, and optical properties of BiVO4 films depend strongly on the deposition time. It is found that BiVO4 layer deposited for 7 min with a cross-section thickness of around 321.1–326.5 nm showed the optimum performance, whereby the photocurrent reached up to ~0.32 mA/cm−2 at 1.23 V vs. RHE. The deposited BiVO4 represents tiny and long petals, similar to “needle” nanostructures, which is embedded closely into compact agglomerates. Such morphology enables the BiVO4 films to perform efficiently as photoanode in PEC cells. Besides, high crystallinity is detected from the sharp peaks of XRD and Raman analysis, as well as good light absorption capability that are the main contributors to the enhancement of PEC performance. In addition to the facile fabrication offered by electrodeposition method, the non-toxic attributes and the impressive PEC performance of the optimum BiVO4 layer could serve as an interesting option for other applications such as gas sensors, solar cells, degradation of pollutants and photocatalytic water splitting