In:
ECS Meeting Abstracts, The Electrochemical Society, Vol. MA2016-01, No. 31 ( 2016-04-01), p. 1567-1567
Abstract:
The development of efficient catalysts for converting water and CO 2 selectively to hydrocarbons using renewable (electrical) energy is considered the “holy grail” of a sustainable energy economy. Electrochemical CO 2 reduction has been demonstrated to form CO, HCOOH, C1 and C2 alcohols on noble metals, 1,2 and alkanes on copper. 3 These technologies are still pre-commercial and limited by three main problems: 1) atom efficiency: significant H 2 production at the expense of the desired product; 2) selectivity: low for a single hydrocarbon product, and 3) electrical efficiency: high overpotential for the reaction. Among the proposed mechanisms on copper, two steps have been postulated as rate-limiting: 1) reductive binding to form adsorbed CO 2 - * and, 2) hydrogen addition to adsorbed CO* forming HCO* 4 . To overcome these barriers, we used three strategies which involve use of catalyst surfaces comprised of binary solids (M x P y ) in which: 1) phosphorous is chosen for its high P-O bond energy needed to stabilize side-on binding of the HCO* and CO 2 - * intermediates via O atom; 2) the M-C bond energy is controlled (choice of M); and 3) an adjustable M-P interatomic spacing that allows C to adopt its favored trigonal binding geometry (ideal sp 2 C hybridized orbitals). We have synthesized four distinct binary transition metal phosphides, having pure and stable crystalline phases and evaluated their performance as catalysts for CO 2 reduction using low surface area (flat) electrodes. This allows for direct observation of catalytic activity on the most stable crystal termination and is directly comparable to Cu-foils reported in the literature. Herein we present results that show CO 2 reduction to CH 4 at -0.6 V, the lowest potential seen thus far to our knowledge. Furthermore, using metal phosphides there is no formation of carbon monoxide, a poisonous gas that is produced in large quantities when copper is employed as catalyst. Supported by Rutgers University and the Science Without Borders CAPES fellowship. (1) Cole, E. B.; Lakkaraju, P. S.; Rampulla, D. M.; Morris, A. J.; Abelev, E.; Bocarsly, A. B. J. Am. Chem. Soc. 2010 , 132 (33), 11539–11551. (2) Barton, E. E.; Rampulla, D. M.; Bocarsly, A. B. J. Am. Chem. Soc. 2008 , 130 (20), 6342–6344. (3) Hori, Y.; Kikuchi, K.; Suzuki, S. Chem. Lett. 1985 , No. 11, 1695–1698. (4) Peterson, A. a.; Abild-Pedersen, F.; Studt, F.; Rossmeisl, J.; Nørskov, J. K. Energy Environ. Sci. 2010 , 3 (9), 1311.
Type of Medium:
Online Resource
ISSN:
2151-2043
DOI:
10.1149/MA2016-01/31/1567
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2016
detail.hit.zdb_id:
2438749-6
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