Anchoring BaII to Pd/Hy WO3-x Nanowires Promotes a Photocatalytic Reverse Water-Gas Shift Reaction.

Surface deposition of BaII on Pd/Hy WO3-x nanowires was developed by using a solution-phase atomic layer deposition process. The procedure involves the generation of Brønsted surface OH sites by H2 spillover on Pd/WO3 , which can then hydrolytically condense with Ba(OEt)2 to produce surface BaII . At just 0.2 at % Ba, CO production by the light-assisted activity of the reverse water-gas shift (RWGS) reaction was observed to increase by about 300 %. In situ DRIFTS studies suggested enhanced CO2 capturing capabilities of a Ba-decorated surface. This study further exemplifies the importance of surface chemistry in optimizing materials for catalysis.

Cu Atoms on Nanowire Pd/HyWO3-x Bronzes Enhance the Solar Reverse Water Gas Shift Reaction.

Nanowire hydrogen bronzes of WO3 nanowires decorated with Pd (Pd/HyWO3-x) were previously demonstrated to effectively capture broadband radiation across the ultraviolet to near-infrared wavelength range and catalyze the reverse water gas shift reaction (RWGS). Herein, we report a synthetic strategy to enhance the performance of this class of photocatalysts by conformally coating Cu atoms onto the surface of Pd/HyWO3-x by anchoring Cu(I)OtBu to the Brønsted acidic protons of the bronze. The resulting materials are characterized by a suite of analytical methods, including electron microscopy and X-ray absorption spectroscopy. In addition, in situ diffuse reflectance infrared Fourier transform spectroscopy demonstrated that for the light-driven RWGS reaction, as little as 0.2 at. % Cu facilitates the formation of surface carboxylate species from CO2, resulting in a 300-500% enhancement in the rate of CO production. This metal anchoring method enables atom precise modification of the surfaces of metal oxide nanomaterials for catalytic applications, circumventing the need for complex and expensive atomic layer deposition processes.