02113nas a2200229   4500008004100000022001400041245008000055210006900135260000900204300002300213490000600236520133300242100002201575700002601597700002101623700002701644700001801671700002801689700002401717700003001741856011201771       2016                        eng d  a1614-683200aLow band gap benzimidazole COF supported Ni3N as highly active OER catalyst0 aLow band gap benzimidazole COF supported Ni3N as highly active O  cDEC   aArticle No:16011890 v63 a<p>Covalent organic frameworks (COFs) have structures and morphologies closely resembling graphenes, whose modular construction permits atomiclevel manipulations. This, combined with their porous structure, makes them excellent catalyst supports. Here, the high electrocatalytic activity of a composite, formed by supporting Ni3N nanoparticles on a benzimidazole COF, for oxygen evolution reaction is shown. The composite oxidizes alkaline water with a near-record low overpotential of 230 mV @ 10 mA cm(-2) (eta(10)). This high activity is attributed to the ability of the COF to confine the Ni3N nanoparticles to size regimes otherwise difficult to obtain and to its low band gap character (1.49 eV) arising from the synergy between the conducting Ni3N nanoparticles and the pi-conjugated COF. The COF itself, as a metalfree self-standing framework, has an oxygen evolution reaction activity with 10 of 400 mV. The periodic structure of the COF makes it serve as a matrix to disperse the catalytically active Ni3N nanoparticles favoring their high accessibility and thereby good charge-transport within the composite. This is evident from the amount of O-2 evolved (230 mmol h(-1) g(-1)), which, to the best of our knowledge, is the highest reported. The work reveals the emergence of COF as supports for electrocatalysts.</p>1 aNandi, Shyamapada1 aSingh, Santosh, Kumar1 aMullangi, Dinesh1 aIllathvalappil, Rajith1 aGeorge, Leena1 aVinod, Chathakudath, P.1 aKurungot, Sreekumar1 aVaidhyanathan, Ramanathan  uhttps://library.ncl.res.in/content/low-band-gap-benzimidazole-cof-supported-ni3n-highly-active-oer-catalyst02884nas a2200205   4500008004100000022001400041245013900055210006900194260000900263300001400272490000700286520212500293100002202418700001602440700001602456700002302472700002802495700002402523856013102547       2021                        eng d  a2041-652000aLithium silicate nanosheets with excellent capture capacity and kinetics with unprecedented stability for high-temperature CO2 capture0 aLithium silicate nanosheets with excellent capture capacity and   cAPR   a4825-48350 v123 a<p>An excessive amount of CO2 is the leading cause of climate change, and hence, its reduction in the Earth's atmosphere is critical to stop further degradation of the environment. Although a large body of work has been carried out for post-combustion low-temperature CO2 capture, there are very few high temperature pre-combustion CO2 capture processes. Lithium silicate (Li4SiO4), one of the best known high-temperature CO2 capture sorbents, has two main challenges, moderate capture kinetics and poor sorbent stability. In this work, we have designed and synthesized lithium silicate nanosheets (LSNs), which showed high CO2 capture capacity (35.3 wt% CO2 capture using 60% CO2 feed gas, close to the theoretical value) with ultra-fast kinetics and enhanced stability at 650 degrees C. Due to the nanosheet morphology of the LSNs, they provided a good external surface for CO2 adsorption at every Li-site, yielding excellent CO2 capture capacity. The nanosheet morphology of the LSNs allowed efficient CO2 diffusion to ensure reaction with the entire sheet as well as providing extremely fast CO2 capture kinetics (0.22 g g(-1) min(-1)). Conventional lithium silicates are known to rapidly lose their capture capacity and kinetics within the first few cycles due to thick carbonate shell formation and also due to the sintering of sorbent particles; however, the LSNs were stable for at least 200 cycles without any loss in their capture capacity or kinetics. The LSNs neither formed a carbonate shell nor underwent sintering, allowing efficient adsorption-desorption cycling. We also proposed a new mechanism, a mixed-phase model, to explain the unique CO2 capture behavior of the LSNs, using detailed (i) kinetics experiments for both adsorption and desorption steps, (ii) in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy measurements, (iii) depth-profiling X-ray photoelectron spectroscopy (XPS) of the sorbent after CO2 capture and (iv) theoretical investigation through systematic electronic structure calculations within the framework of density functional theory (DFT) formalism.</p>1 aBelgamwar, Rajesh1 aMaity, Ayan1 aDas, Tisita1 aChakraborty, Sudip1 aVinod, Chathakudath, P.1 aPolshettiwar, Vivek  uhttps://library.ncl.res.in/content/lithium-silicate-nanosheets-excellent-capture-capacity-and-kinetics-unprecedented-stability