Integration of 2D printing technologies for AV2O6 (A=Ca, Sr, Ba)-MO (M=Cu, Ni, Zn) photocatalyst manufacturing to solar fuels production using seawater

The non-polluting nature of photocatalytic H-2 production makes of interest the study of semiconductors for this process. Scale-up of the photocatalytic hydrogen process to a pilot plant requires the photocatalyst's immobilization to enhance the charge transfer and facilitate its recovery. In this work, screen-printed films from the AV(2)O(6) (A = Ca, Sr, Ba) semiconductor family were fabricated and evaluated in photocatalytic water splitting for H-2 production in distilled water and seawater under UVA light. The films exhibited similar to 3.1 eV band gaps, high crystallinity, and heterogeneous morphologies. BaV2O6 film exhibited the highest H-2 production in distilled water (691 mmol/g), related to the synergistic effect between a higher crystallinity and traces of V+4 species that decrease the recombination of the photogenerated charges. Also, to take advantage of the dissolved species in seawater that could act as sacrificial agents, the BaV2O6 film was evaluated in seawater, in which H-2 production was up to 6 times higher (4374 mmol/g) than in distilled water. The BaV2O6 film was decorated with simple oxides (CuO, NiO, and ZnO) by the ink-jet printing technology to increase its photocatalytic performance for H-2 production. The highest efficiency with distilled water was obtained with the BaV2O6-CuO film, which reached an H-2 production up to 30 times higher than the bare BaV2O6, own to the n-p heterostructure formation that enhances the charge transport in the photocatalytic process. When the BaV2O6-CuO film was evaluated in seawater, a more constant H-2 production was observed; moreover, the efficiency was similar compared to the production in distilled water (20,563 mmol/g). To elucidate the seawater compounds that most influence the H-2 production, a two levels PlacketteBurman experiments design was carried out in simulated seawater. The analysis revealed that the SO42- ions fromthe CaSO4 could be decreasing the H-2 production by acting as Lewis's acid sites that trap the photogenerated e(-) competing for its usage with the Hthorn. Additionally, the Cl- ions and the HCO3- reduction improved the HCOOH production from simulated seawater, reaching 26 times a higher production (23,333 mmol/g) than in distilled water. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Photocatalytic hydrogen production using AV(2)O(6) semiconductor films showed high efficiency in both distilled water and seawater. Decorated with simple oxides, such as CuO, NiO, and ZnO, the photocatalytic performance of the BaV2O6 film was significantly enhanced. Furthermore, seawater compounds were found to influence the H-2 production, with SO42- ions from CaSO4 inhibiting the process while Cl- ions and HCO3- reduction promoting the production of HCOOH.