TY  - JOUR
A1  - Fischer, Sabrina
A1  - Schmidt, Johannes
A1  - Strauch, Peter
A1  - Thomas, Arne
T1  - An anionic microporous polymer network prepared by the polymerization of weakly coordinating anions
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
KW  - borates
KW  - conjugated microporous polymers
KW  - covalent organic frameworks
KW  - ion exchange
KW  - weakly coordinating ions
Y1  - 2013
U6  - https://doi.org/10.1002/anie.201303045
SN  - 1433-7851
SN  - 1521-3773
VL  - 52
IS  - 46
SP  - 12174
EP  - 12178
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Lai, Feili
A1  - Feng, Jianrui
A1  - Heil, Tobias
A1  - Tian, Zhihong
A1  - Schmidt, Johannes
A1  - Wang, Gui-Chang
A1  - Oschatz, Martin
T1  - Partially delocalized charge in Fe-doped NiCo2S4 nanosheet-mesoporous carbon-composites for high-voltage supercapacitors
JF  - Journal of materials chemistry : A, Materials for energy and sustainability
N2  - Unraveling the effect of transition-metal doping on the energy storage properties of bimetallic sulfides remains a grand challenge. Herein, we construct bimetallic sulfide nanosheets and hence deliberately introduce transition-metal doping domains on their surface. The resulting materials show not only an enhanced density of states near the Fermi level but also partially delocalized charge as shown by density functional theory (DFT) calculations. Fe-doped NiCo2S4 nanosheets wrapped on N,S-doped ordered mesoporous carbon (Fe-NiCo2S4@N,S-CMK-3) are prepared, which show an enhanced specific capacitance of 197.8 F g(-1) in ionic liquid-based supercapacitors at a scan rate of 2 mV s(-1). This is significantly higher as compared to the capacitance of 155.2 and 135.9 F g(-1) of non-iron-doped NiCo2S4@N,S-CMK and Fe-NiCo2S4@CMK-3 electrodes, respectively. This result arises from the enhanced ionic liquid polarization effect and transportation ability from the Fe-NiCo2S4 surface and N,S-CMK-3 structure. Furthermore, the importance of matching multi-dimensional structures and ionic liquid ion sizes in the fabrication of asymmetric supercapacitors (ASCs) is demonstrated. As a result, the ASC device exhibits a high energy density of 107.5 W h kg(-1) at a power density of 100 W kg(-1) in a working-voltage window of 4 V when using Fe-NiCo2S4@N,S-CMK-3 and N,S-CMK-3 as positive and negative electrodes, respectively. This work puts forward a new direction to design supercapacitor composite electrodes for efficient ionic liquid coupling.
Y1  - 2019
U6  - https://doi.org/10.1039/c9ta06250e
SN  - 2050-7488
SN  - 2050-7496
VL  - 7
IS  - 33
SP  - 19342
EP  - 19347
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Qin, Qing
A1  - Zhao, Yun
A1  - Schmallegger, Max
A1  - Heil, Tobias
A1  - Schmidt, Johannes
A1  - Walczak, Ralf
A1  - Gescheidt-Demner, Georg
A1  - Jiao, Haijun
A1  - Oschatz, Martin
T1  - Enhanced Electrocatalytic N-2 Reduction via Partial Anion Substitution in Titanium Oxide-Carbon Composites
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - The electrochemical conversion of N-2 at ambient conditions using renewably generated electricity is an attractive approach for sustainable ammonia (NH3) production. Considering the chemical inertness of N-2, rational design of efficient and stable catalysts is required. Therefore, in this work, it is demonstrated that a C-doped TiO2/C (C-TixOy/C) material derived from the metal-organic framework (MOF) MIL-125(Ti) can achieve a high Faradaic efficiency (FE) of 17.8 %, which even surpasses most of the established noble metal-based catalysts. On the basis of the experimental results and theoretical calculations, the remarkable properties of the catalysts can be attributed to the doping of carbon atoms into oxygen vacancies (OVs) and the formation of Ti-C bonds in C-TixOy. This binding motive is found to be energetically more favorable for N-2 activation compared to the non-substituted OVs in TiO2. This work elucidates that electrochemical N-2 reduction reaction (NRR) performance can be largely improved by creating catalytically active centers through rational substitution of anions into metal oxides.
KW  - ammonia synthesis
KW  - anion substitution
KW  - MOF-derived catalysts
KW  - N-2 fixation
KW  - non-noble metal catalysts
Y1  - 2019
U6  - https://doi.org/10.1002/anie.201906056
SN  - 1433-7851
SN  - 1521-3773
VL  - 58
IS  - 37
SP  - 13101
EP  - 13106
PB  - Wiley-VCH
CY  - Weinheim
ER  -