A commercially available palladium N-heterocyclic carbene (Pd-NHC) precatalyst is used to initiate chain-growth polymerization of 2-bromo-3-hexyl-5-trimethylstannylthiophene. The molecular weight of the resultant poly(3-hexylthiophene) can be modulated (7 to 73 kDa, Đ = 1.14 to 1.53) by varying the catalyst concentration. Mass spectrometry data confirm control over the polymer end groups and (1)H NMR spectroscopy reveals that the palladium catalyst is capable of "ring-walking". A linear relationship between Mn and monomer conversion is observed. Atomic force microscopy and X-ray scattering verify the regioregular nature of the resultant polythiophene.

Copolymer-templated nitrogen-doped carbon (CTNC) films deposited on glassy carbon were used as electrodes to study electrochemically driven hydrogen evolution reaction (HER) in 0.5 M H2SO4. The activity of these materials was extremely enhanced when a platinum counter electrode was used instead of a graphite rod and reached the level of commercial Pt/C electrodes. Postreaction scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) measurements of electrode surfaces revealed that incorporation of even extremely low amounts of Pt resulted in this considerable gain of HER activity. High resolution XPS analysis and density functional theory (DFT) calculations confirmed that pyridinic nitrogen atoms act as active sites for Pt coordination and deposition. The Pt can be incorporated in both molecular (Pt(2+)) and metallic (Pt(0)) form. This study shows that great caution must be taken when designing "metal-free" HER catalysts based on N-doped carbons.

ARTICLE This journal isAbstract In this report we demonstrate the superior performance of dye-sensitized solar cells (DSSCs) with novel, metal-free counter electrodes (CEs) comprised of copolymer-templated nitrogen-enriched nanocarbons (CTNCs) with well-controlled morphology, nanoporosity, and nitrogen content. This superior performance is due to the high catalytic activity of CTNCs toward the reduction of Co(bpy) 3 2+/3+ , as evidenced by unusually low charge transfer resistance (R CT ) at the CE/electrolyte interface. The observed activity is attributed to the combination of CTNCs' high surface area afforded by a three-dimensional, hierarchical pore structure, and to their unique electronic properties stemming from the presence of nitrogen heteroatoms located on the edges of nanographitic domains. Altogether, use of CTNC CEs enhanced the efficiency and fill factor (FF) of JK-306 dye, Co(bpy) 3 2+/3+ redox couple based DSSCs at one sun illumination up to, respectively, 10.32% and 73.5%, pointing to the considerable promise of these materials as an attractive alternative to costly Pt-based CEs. Interestingly, use of CTNCs did not lead to the analogous beneficial lowering of the R CT in I − /I 3 − redox couple based N719sensitized DSSCs, limiting their FF and short circuit current density (J SC ). This chemical specificity indicates that the type of nitrogen bonding configurations, rather than the total Ncontent, is the key factor determining the catalytic activity. Cihlář, J.; Chang, C.-Y.; Cheng, C.; Teng, H. Materials Today 2013, 16, 78. 5 (a) Ra, E. J.; Raymundo-Pinero, E.; Lee, Y. H.; Beguin, F. Carbon 2012, 22, 9639. (d) Murakami, T. N.; Ito, S.; Wang, Q.; Nazeeruddin, M. K.; Bessho, T.; Cesar, I.; Liska, P.; Humphry-Baker, R.; Comte, P.; Péchy, P.; Grätzel, M. Journal of The Electrochemical Society 2006, 153, A2255. (e) Fang, B.; Kim, M.; Fan, S.-Q.; Kim, J. H.; Wilkinson, D. P.; Ko, J.; Yu, J.-S. Journal of Materials Chemistry 2011, 21, 8742. (f) Cai, X.; Hou, S.; Wu, H.; Lv, Z.; Fu, Y.; Wang, D.; Zhang, C.; Kafafy, H.; Chu, Z.; Zou, D. Journal Name ARTICLE 2010, 4, 6203. 25 Kavan, L.; Yum, J. H.; Grätzel, M. ACS Nano 2010, 5, 165. 26 Lim, K.; Ju, M. J.; Song, J.; Choi, I. T.; Do, K.; Choi, H.; Song, K.; Kim, H. K.; Ko, J. ChemSusChem 2013, 6, 1425. 27 Song, B. J.; Song, H. M.; Choi, I. T.; Kim, S. K.; Seo, K. D.; Kang, M. S.; Lee, M. J.; Cho, D. W.; Ju, M. J.; Kim, H. K.

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