Automated electrochemical synthesis and characterization of TiO2 supported Au nanoparticle electrocatalysts

Automated systems for electrochemical synthesis and high throughput screening of catalytic materials were developed and used to prepare a library of nanoparticulate gold supported on TiO2. A two-dimensional array (library) of Au was synthesized by pulsed cathodic electrodeposition onto a thermally oxidized titanium dioxide substrate. Variations in particle size across the library were created by changing the deposition time (number of pulses). Longer deposition times led to increased Au particle sizes and greater density of Au on the surface. High throughput electrochemical screening was used to characterize the electrocatalytic activity of the supported Au clusters for: (1) photoelectrochemical water oxidation and (2) CO electro-oxidation. Au films synthesized with 5 ms pulses between 3 and 10 s of total deposition time demonstrated the greatest activity for photodecomposition of water (20–40% greater than pure TiO2). For CO electro-oxidation, it was found that the smallest Au particle (<10 nm, 1 s total deposition time) was most active, consistent with previous research in this area.