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TRANSCRIPT
Gold catalyst reactivity for CO2 electro-reduction: from nano particle to layer
Eduardus Budi Nursanto a,b, Hyo Sang Jeon a,b, Cheonghee Kim a, Michael Shincheon Jee a, Jai Hyun Koh a, Yun Jeong Hwang a,b,*, Byoung Koun Mina,b,c,*
aClean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of KoreabDepartment of Clean Energy and Chemical Engineering, Korea University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Daejeon 305-333, Republic of KoreacGreen School, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-713, Republic of Korea
*Corresponding author:
Tel: + 82-2-958-5227, Fax: + 82-2-958-5809, [email protected] (Y. J. Hwang)
Tel: + 82-2-958-5853, Fax: + 82-2-958-5809, [email protected] (B.K. Min)
Keywords: CO2 electro-reduction, gold catalysts, e-beam deposition
Figure S1. HR-TEM images of Au-T samples with respect to Au film thickness (nm) on quartz crystal microbalance (QCM) of e-beam deposition apparatus: (a) Au-0.5, (b) Au-4, and (c) Au-7. Based on d-spacing analysis, low coverage Au-T samples (Au-0.5 and Au-4) were found to have the same high crystallinity to the high coverage one (Au-7). (d) SEM image of Au-30 sample showing the uniform layered film nature.
Figure S2. XRD patterns of the bare carbon paper, Au foil and Au-T samples with respect to Au film thickness (nm) on quartz crystal microbalance (QCM) of e-beam deposition apparatus. Inset is magnified XRD patterns at 2Ɵ 37- 46o, showing the higher intensity of (111) phase and evolution of (200) phase for the high coverage Au-T samples (Au-7, Au 10 and Au-30).
Figure S3. Total current densities of Au-T samples (Au-2, Au-3, Au-4, Au-5, and Au-7; complement with Figure 2) as a function of bias potential, showing the enhanced activity for high coverage Au-T samples.
Figure S4. CO Faradaic efficiencies of bare carbon paper, Au foil, small nanoparticles (Au-0.5 and Au-1), aggregated clusters (Au-4) and layered film (Au-30) Au-T samples as a function of bias potential.
Figure S5. CO production rates of bare carbon paper, small nanoparticles (Au-0.5 and Au-1), aggregated clusters (Au-4) and layered film (Au-30) Au-T samples and Au-foil as a function of bias potential.
Figure S6. Tafel plots for CO2 electro-reduction of Au-T samples. Au-1 (low coverage Au sample) and Au-10 (high coverage Au sample) were found to have the similar Tafel slope values of 115 and 110 mV/dec, respectively.