- Metathetic synthesis of lead cyanamide as a p-type semiconductor
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Lead cyanamide PbNCN was synthesized by solid-state metathesis between PbCl2 and Na2NCN in a 1?:?1 molar ratio, and its structure was confirmed from Rietveldrefinement of X-ray data. Electronic-structure calculations of HSE06 density-functional type revealPbNCN to be an indirect semiconductor with a band gap of 2.4 eV, in remarkable quantitative agreement with the measured value. Mott-Schottky experiments demonstrate PbNCN to be a p-type semiconductor with a flat-band potential of 2.3 eV vs. the reversible hydrogen electrode (RHE) which is commonly used to estimate the value of the valence band edge position. Moreover, thin films of powderous PbNCN were assembled into a photoelectrode for photoelectrochemical water splitting. On the example of p-type PbNCN, this study provides the first experimental evidence that MNCN compounds can be applied as photocathodes for reductive reactions in photoelectrochemical cells.
- Corkett, Alex J.,Dronskowski, Richard,Ku?trowski, Piotr,Luo, Dongbao,Ma, Zili,Qiao, Xianji,Rokicinska, Anna,Slabon, Adam
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- High-Pressure Behavior of Lead Cyanamide PbNCN
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The high-pressure behavior of lead cyanamide, PbNCN, was studied using the diamond anvil cell technique and in situ X-ray powder diffraction at room temperature. By employing a third-order Birch–Murnaghan equation of state, a zero-pressure bulk modulus of K0 = 19(2) GPa was determined, characterizing PbNCN as a very soft material. Additionally, the first linear compression moduli for the inorganic cyanamide were determined to be Ka0 = 145(7) GPa, Kb0 = 37.7(7) GPa, and Kc0 = 15.5(2) GPa. DFT total-energy calculations targeting on the Pb2+ coordination indicate a transition from a typical compression behavior of a two-dimensional layered structure to a more complex one, which was furthermore analyzed by chemical-bonding analysis. Instead of a changing shape of the soft cyanamide unit, we observe an unexpected flattening of the corrugated double layers.
- M?ller, Andreas,Konze, Philipp M.,Dronskowski, Richard
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- Nonaqueous synthesis of metal cyanamide semiconductor nanocrystals for photocatalytic water oxidation
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Herein, we report nonaqueous synthesis of metal cyanamide semiconductor nanocrystals, including Ag2NCN nanorods (NRs), ZnNCN NRs and PbNCN nanoparticles. The as-prepared Ag2NCN NRs with a band gap of 2.35 eV are applied as photocatalysts for water oxidation. Their oxygen evolution rate (280.7 μmol h-1 g-1) is much higher than that of Ag2NCN microcrystals (24.0 μmol h-1 g-1).
- Zhao, Wei,Pan, Jie,Huang, Fuqiang
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supporting information
p. 1575 - 1578
(2018/02/14)
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- Crystal structure refinement of lead cyanamide and the stiffness of the cyanamide anion
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The crystal structure of lead cyanamide, PbNCN, has been refined on the basis of a single crystal grown from solution. PbNCN crystallizes in space group Pnma (Z = 4) with a = 555.66(4) pm, b = 386.77(2) pm, and c = 1173.50(8) pm. The cyanamide anion exhibits C-N bond lengths of 116 pm and 130 pm, and the N-C-N angle is 176°. Quantum-chemical DFT calculations indicate that the cyanamide unit is comparatively easy to distort.
- Liu, Xiaohui,Decker, Andrea,Schmitz, Dieter,Dronskowski, Richard
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p. 103 - 105
(2008/10/08)
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