Intervening Bismuth Tungstate with DNA Chain Assemblies: A Perception toward Feedstock Conversion via Photoelectrocatalytic Water Splitting.

An advanced approach with DNA-mediated bismuth tungstate (Bi2WO6) one-dimensional (1-D) nanochain assemblies for hydrogen production with 5-fold enhanced photoelectrochemical (PEC) water splitting reaction is presented. The creation of new surface states upon DNA modification mediates the electron transfer in a facile manner for a better PEC process. The UV-Vis-DRS analysis results a red shift in the optical absorption phenomenon with the interference of DNA modification on Bi2WO6, and, thus, the band gap was tuned from 3.05 eV to 2.71 eV. The applied bias photon-to-current efficiency (ABPE) was calculated and shows a maximum for the Bi2WO6@DNA-2 (25.22 × 10-4%), compared to pristine Bi2WO6 (7.76 × 10-4%). Furthermore, the idea of practical utility of produced hydrogen from PEC is established for the first time with photocatalytic feedstock conversion to platform chemicals using cinnamaldehyde, 2-hydroxy-1-phenylethanone, and 2-(3-methoxyphenoxy)-1-phenylethanone in large scale by hydrogenation and/or hydrogenolysis reactions under eco-friendly green conditions with external hydrogen pressure in an aqueous mixture. Also, the recyclability experiment delivered good yields, which further confirm the robustness of the developed catalyst.

Bi2WO6 and FeWO4 Nanocatalysts for the Electrochemical Water Oxidation Process.

Polyvinylpyrrolidone (PVP)-assisted nanocatalyst preparation was succeeded by employing a controlled solvothermal route to produce efficient electrodes for electrochemical water-splitting applications. Bi2WO6 and FeWO4 nanocatalysts have been confirmed through the strong signature of (113) and (111) crystal planes, respectively. The binding natures of Bi-W-O and Fe-W-O have been thoroughly discussed by employing X-ray photoelectron spectroscopy which confirmed the formation of Bi2WO6 and FeWO4. The freestanding nanoplate array morphology of Bi2WO6 and the fine nanosphere particle morphology of FeWO4 nanocatalysts were revealed by scanning electron microscopy images. With these confirmations, the fabrication of durable, long-term electrodes for electrochemical water splitting has been subjected to efficient oxidation of water, confirmed by obtaining 2.79 and 1.96 mA/g for 0.5 g PVP-assisted Bi2WO6 and FeWO4 nanocatalysts, respectively. The water oxidation mechanism of both nanocatalysts has been revealed with the support of 24 h stability test over continuous water oxidation and faster charge transfer achieved by the smaller Tafel slope values of 75 and 78 mV/dec, respectively. Generally, these nanocatalysts are utilized for photocatalytic applications. The present study revealed the PVP-assisted synthesis to produce electrocatalytically active nanocatalysts and their electrochemical water-splitting mechanism which will offer a pathway for research interests with regard to the production of multifunctional nanocatalysts for both electro- and photocatalytic applications in the near future.