scholarly journals Recent Progress with Pincer Transition Metal Catalysts for Sustainability

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 773 ◽  
Author(s):  
Luca Piccirilli ◽  
Danielle Lobo Justo Pinheiro ◽  
Martin Nielsen
Keyword(s):  
Transition Metal ◽  
Energy Production ◽  
Transition Metal Catalysts ◽  
Hydrogen Release ◽  
Pincer Complexes ◽  
Catalyst Loading ◽  
Sustainable Solutions ◽  
Long Term Stability ◽  
Low Catalyst Loading

Our planet urgently needs sustainable solutions to alleviate the anthropogenic global warming and climate change. Homogeneous catalysis has the potential to play a fundamental role in this process, providing novel, efficient, and at the same time eco-friendly routes for both chemicals and energy production. In particular, pincer-type ligation shows promising properties in terms of long-term stability and selectivity, as well as allowing for mild reaction conditions and low catalyst loading. Indeed, pincer complexes have been applied to a plethora of sustainable chemical processes, such as hydrogen release, CO2 capture and conversion, N2 fixation, and biomass valorization for the synthesis of high-value chemicals and fuels. In this work, we show the main advances of the last five years in the use of pincer transition metal complexes in key catalytic processes aiming for a more sustainable chemical and energy production.

scholarly journals Physics of Relativistic Jets on Sub-Milliarcsecond Scales

1984 ◽  
Vol 110 ◽  
pp. 207-214
Author(s):  
Martin J. Rees
Keyword(s):  
Energy Production ◽  
Galactic Nuclei ◽  
Primary Energy ◽  
Relativistic Jets ◽  
Short Term ◽  
X Ray ◽  
Long Term Stability ◽  
Extended Sources ◽  
Vlbi Data

The observed superluminal components have (deprojected) lengths of ~ 1020 cm, and imply relativistic bulk motions on these scales. There are, however, persuasive reasons for attributing the primary energy production to scales 1014–1015 cm. Moreover, the initial bifurcation and collimation must also be imposed on these small scales if the long-term stability of the jet axis in extended sources is due to the gyroscopic effect of a spinning black hole (Rees 1978). The issues I shall address in this talk are: how the jet gets from ~ 1015cm to ~ 1019 cm; and what VLBI data can tell us about the properties of galactic nuclei on scales below ~ 1019 cm — scales where optical and X-ray studies provide some evidence, but where there is no short-term hope of achieving spatial resolution.

Earth-abundant 3d-transition-metal catalysts for lignocellulosic biomass conversion

2021 ◽  
Author(s):  
Yunchao Feng ◽  
Sishi Long ◽  
Xing Tang ◽  
Yong Sun ◽  
Rafael Luque ◽  
...  
Keyword(s):  
Transition Metal ◽  
Lignocellulosic Biomass ◽  
Biomass Conversion ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
P Transformation ◽  
Earth Abundant ◽  
Fast Development ◽  
Lignocellulosic Biomass Conversion

Transformation of biomass to chemicals and fuels is a long-term goal in both science and industry. Here, we review the fast development and recent advances of 3d-metal-based catalysts including Cu, Fe, Co, Ni and Mn in lignocellulosic biomass conversion.

scholarly journals An Efficient Trap Passivator for Perovskite Solar Cells: Poly(propylene glycol) bis(2-aminopropyl ether)

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Ningli Chen ◽  
Xiaohui Yi ◽  
Jing Zhuang ◽  
Yuanzhi Wei ◽  
Yanyan Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Propylene Glycol ◽  
Energy Production ◽  
Power Conversion ◽  
Perovskite Solar Cells ◽  
Trap States ◽  
Long Term Stability ◽  
Device Lifetime ◽  
Poly Propylene

AbstractPerovskite solar cells (PSCs) are regarded as promising candidates for future renewable energy production. High-density defects in the perovskite films, however, lead to unsatisfactory device performances. Here, poly(propylene glycol) bis(2-aminopropyl ether) (PEA) additive is utilized to passivate the trap states in perovskite. The PEA molecules chemically interact with lead ions in perovskite, considerably passivate surface and bulk defects, which is in favor of charge transfer and extraction. Furthermore, the PEA additive can efficiently block moisture and oxygen to prolong the device lifetime. As a result, PEA-treated MAPbI3 (MA: CH3NH3) solar cells show increased power conversion efficiency (PCE) (from 17.18 to 18.87%) and good long-term stability. When PEA is introduced to (FAPbI3)1-x(MAPbBr3)x (FA: HC(NH2)2) solar cells, the PCE is enhanced from 19.66 to 21.60%. For both perovskites, their severe device hysteresis is efficiently relieved by PEA.

scholarly journals Unraveling the Effect of Aromatic Groups in Mn(I)NNN Pincer Complexes on Carbon Dioxide Activation Using Density Functional Study

2021 ◽  
Vol 9 ◽  
Author(s):  
Saurabh Vinod Parmar ◽  
Vidya Avasare ◽  
Sourav Pal
Keyword(s):  
Carbon Dioxide ◽  
Transition Metal ◽  
Density Functional ◽  
Value Added ◽  
Catalytic Performance ◽  
Transition Metal Catalysts ◽  
Functional Study ◽  
Pincer Complexes ◽  
The Impact ◽  
Hydrogenation Of Carbon Dioxide

Carbon dioxide utilization is necessary to reduce carbon footprint and also to synthesize value-added chemicals. The transition metal pincer complexes are attractive catalysts for the hydrogenation of carbon dioxide to formic acid. There is a need to understand the factors affecting the catalytic performance of these pincer complexes through a structure–activity relationship study using computational methods. It is a well-established fact that aromatic functionalities offer stability and selectivity to transition metal catalysts. However, their impact on the performance of the catalysts is lesser known in the case of metal pincer complexes. Hence, it is necessary to investigate the catalytic performance of Mn(I)NNN pincer complexes with variably activated aromatic functionalities. In this context, 15 catalysts are designed by placing different types of aromatic rings at the pincer carbons and two terminal nitrogen of Mn(I)NNN pincer complexes. A benzene moiety, placed at C2–C3 carbons of Mn(I)NNN pincer complex with identical aromatic groups at the terminal nitrogen, is found to be most efficient toward CO2 hydrogenation than the rest of the catalysts. On the other hand, when N,N-dimethyl aniline is placed at C2–C3 carbons of Mn(I)NNN pincer complexes, then the catalytic performance is significantly decreased. Thus, the present study unravels the impact of aromatic groups in Mn(I)NNN pincer complexes toward the catalytic hydrogenation of carbon dioxide.

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