Alternative Catalyst for CO2 Electrochemical Reduction

Abstract

Direct electrocatalytic conversion of CO2 to hydrocarbons is a promising alternative for the production of carbon based chemicals. Ideally, the driving force for this process would be electricity from renewable sources, making this process CO2 neutral.1 Copper is the most studied material as catalyst for CO2 reduction reaction (CO2RR) given its unique ability to produce hydrocarbons in considerable amounts. Nevertheless, the reaction’s poor energy efficiency and selectivity remain a major challenge.2 Therefore the technological viability of this process is contingent on the development of novel and efficient catalyst. In recent years different groups have demonstrated that oxide derived copper foil catalysts exhibit lower onset potentials for CO2RR and high selectivities towards C2 products.3,4 Future applications, however, will require the use of supported nanoparticles. Herein we will present the use of Cu2O nanoparticles as catalyst for this process. We demonstrate that these nanoparticles have a lower onset potential for CO2RR in comparison with metallic Cu, which makes them a promising catalyst for this process. Moreover we will discuss the use of alternative catalyst such as heteroatom-doped carbon.5 We show that these materials meet and exceed the activity and selectivity of traditional Au catalysts for the production of syngas, offering a cost-effective alternative. Furthermore, we provide evidence that sufficiently strong interaction between CO and the metal enables the protonation of CO to form hydrocarbons. In order to get more insight into the role of the metal atom, changes in the chemical stat under operando conditions observed via X-ray absorption fine-structure spectroscopy (XAFS) will be also discussed. Figure 1: Scheme of the as heteroatom-doped carbon catalyst for CO2RR. b) Faradaic selectivities of CO and H2 after 10 min reaction at constant electrode potential in CO2 saturated 0.1M KHCO3 at 0.785 mg/cm2 catalyst loading. Lines to guide the eye. References (1) Gattrell, M.; Gupta, N.; Co, A. Ener. Convers. Manag. 007, 48, 1255. (2) Kortlever, R.; Shen, J.; Schouten, K. J. P.; Calle-Vallejo, F.; Koper, M. T. M. J.Phys. Chem. Lett. 2015, 4073. (3) Li, C. W.; Kanan, M. W. J. Am. Chem. Soc. 2012, 134, 7231. (4) Kim, D.; Lee, S.; Ocon, J. D.; Jeong, B.; Lee, J. K.; Lee, J. Phys. Chem. Chem. Phys. 2015, 17, 824. (5) Varela, A. S.; Ranjbar Sahraie, N.; Steinberg, J.; Ju, W.; Oh, H.-S.; Strasser, P. Angew. Chem. Int. Ed. 2015, 54, 10758. Figure 1