The Fast-Track Water Oxidation Channel on BiVO4 Opened by Nitrogen Treatment.

BiVO4 is one of the most promising photoanode materials for water-splitting systems. Nitrogen incorporation into a BiVO4 surface overcomes the known bottleneck in its charge-transfer kinetics into the electrolyte. We explored the role of nitrogen in the surface charge recombination and charge-transfer kinetics by employing transient photocurrent spectroscopy at the time scale of surface recombination and water oxidation kinetics, transient absorption spectroscopy, and X-ray photoelectron spectroscopy. We attributed the activity enhancement mechanism to the accelerated V5+/V4+ redox process, in which incorporated nitrogen suppresses a limiting surface recombination channel by increasing the oxygen vacancies.

Strong Light-Matter Interactions in Au Plasmonic Nanoantennas Coupled with Prussian Blue Catalyst on BiVO4 for Photoelectrochemical Water Splitting.

Invited for this month's cover is the group of Ferdi Karadas and Ekmel Ozbay at Bilkent University. The image proposes a hybrid architecture, in which the semiconductor photoactive host is coupled to a plasmonic particle and a catalyst, to significantly substantiate the photoactivity of the cell. The Full Paper itself is available at 10.1002/cssc.202000294.

Strong Light-Matter Interactions in Au Plasmonic Nanoantennas Coupled with Prussian Blue Catalyst on BiVO4 for Photoelectrochemical Water Splitting.

A facial and large-scale compatible fabrication route is established, affording a high-performance heterogeneous plasmonic-based photoelectrode for water oxidation that incorporates a CoFe-Prussian blue analog (PBA) structure as the water oxidation catalytic center. For this purpose, an angled deposition of gold (Au) was used to selectively coat the tips of the bismuth vanadate (BiVO4 ) nanostructures, yielding Au-capped BiVO4 (Au-BiVO4 ). The formation of multiple size/dimension Au capping islands provides strong light-matter interactions at nanoscale dimensions. These plasmonic particles not only enhance light absorption in the bulk BiVO4 (through the excitation of Fabry-Perot (FP) modes) but also contribute to photocurrent generation through the injection of sub-band-gap hot electrons. To substantiate the activity of the photoanodes, the interfacial electron dynamics are significantly improved by using a PBA water oxidation catalyst (WOC) resulting in an Au-BiVO4 /PBA assembly. At 1.23 V (vs. RHE), the photocurrent value for a bare BiVO4 photoanode was obtained as 190 µA cm-2 , whereas it was boosted to 295 µA cm-2 and 1800 µA cm-2 for Au-BiVO4 and Au-BiVO4 /PBA, respectively. Our results suggest that this simple and facial synthetic approach paves the way for plasmonic-based solar water splitting, in which a variety of common metals and semiconductors can be employed in conjunction with catalyst designs.