Identification of optimal solar fuel electrocatalysts via high throughput in situ optical measurements
- PDF / 538,948 Bytes
- 9 Pages / 584.957 x 782.986 pts Page_size
- 75 Downloads / 174 Views
an Jin Engineering Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
John M. Gregoirea) Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, California 91125, USA (Received 26 July 2014; accepted 25 September 2014)
Many solar fuel generator designs involve illumination of a photoabsorber stack coated with a catalyst for the oxygen evolution reaction (OER). In this design, impinging light must pass through the catalyst layer before reaching the photoabsorber(s), and thus optical transmission is an important function of the OER catalyst layer. Many oxide catalysts, such as those containing elements Ni and Co, form oxide or oxyhydroxide phases in alkaline solution at operational potentials that differ from the phases observed in ambient conditions. To characterize the transparency of such catalysts during OER operation, 1031 unique compositions containing the elements Ni, Co, Ce, La, and Fe were prepared by a high throughput inkjet printing technique. The catalytic current of each composition was recorded at an OER overpotential of 0.33 V with simultaneous measurement of the spectral transmission. By combining the optical and catalytic properties, the combined catalyst efficiency was calculated to identify the optimal catalysts for solar fuel applications within the material library. The measurements required development of a new high throughput instrument with integrated electrochemistry and spectroscopy measurements, which enables various spectroelectrochemistry experiments.
I. INTRODUCTION
The efficient electrochemical conversion of H2O and CO2 into fuel is an attractive technique for storing energy produced by intermittent renewable energy sources such as solar or wind. Feasible large-scale deployment of this type of system requires the discovery of improved electrocatalysts containing only earth-abundant elements.1–3 In particular, the 4-electron oxygen evolution reaction (OER) is kinetically slow and improved catalysts are required for artificial photosynthesis and electrolysis of hydrogen or carbon-containing fuels.2 Because a robust fundamental understanding of the basic science and mechanistic details of multi-electron heterogeneous electrocatalysis is lacking, an efficient high throughput synthesis and property screening methodology is well suited to empirically discover the requisite new catalytic materials.4–12 Mixed metal oxides in the (Ni–Fe)Ox and (Ni–Co)Ox composition spaces are among the most active and most studied OER catalysts,2,13–16,17–20 and combinatorial methods have been deployed to search pseudo-ternary spaces for improved OER catalysts.7–9,11 We have established high throughput a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2014.296 442
J. Mater. Res., Vol. 30, No. 3, Feb 14, 2015
http://journals.cambridge.org
Downloaded: 11 Mar 2015
methods to systematically investigate the performance of pseudo-quaternary material libraries as OER
Data Loading...
