02139nas a2200253   4500008004100000022001400041245016900055210006900224260000800293300001400301490000600315520119100321653001901512653003001531653002001561653003201581653002801613100002801641700002501669700001801694700002101712700002401733856012801757       2017                        eng d  a2196-021600aNitrogen-doped graphene with a three-dimensional architecture assisted by carbon nitride tetrapods as an efficient metal-free electrocatalyst for hydrogen evolution0 aNitrogendoped graphene with a threedimensional architecture assi  cOCT  a2643-26520 v43 aCurrent polymer membrane-based electrolyzers use Pt as a cathode catalyst for efficient reduction of water. The high cost of Pt-based catalysts forces researchers to develop alternative electrocatalysts. Here, a simple strategy has been proposed to synthesize a metal-free electrocatalyst for the hydrogen evolution reaction (HER) by high-temperature annealing of graphene oxide-coated melamine foam. The prepared catalyst possesses both structural and functional advantages with its three-dimensional (3D) interconnected arms of carbon nitride (CNx) backbone wrapped with nitrogen-doped graphene (N-RGO) sheets (CNx@N-RGO). CNx@N-RGO faces only a 193 mV overpotential to achieve a current density of 10mAcm(-2), which is far superior to the previously reported Pt-free systems. Along with the high exchange current density 34.7 x 10(-6)A cm(-2) and low Tafel slope of 54 mV dec(-1), CNx@N-RGO follows a Volmer-Heyrovsky mechanism for the HER. DFT calculations show that the synergy between CNx and N-RGO facilitates good electrical coupling between the two moieties and provides optimal binding to H+ ions on the catalyst that, in turn, results in efficient reduction of hydrogen ions.10acarbon nitride10aDensity functional theory10aelectrocatalyst10ahydrogen evolution reaction10anitrogen doped graphene1 aGangadharan, Pranav, K.1 aUnni, SreeKuttan, M.1 aKumar, Nandha1 aGhosh, Prasenjit1 aKurungot, Sreekumar  uhttps://library.ncl.res.in/content/nitrogen-doped-graphene-three-dimensional-architecture-assisted-carbon-nitride-tetrapods02878nas a2200253   4500008004100000022001400041245014000055210006900195260000900264300001600273490000700289520193800296653003202234653002902266653002402295653002702319653002802346653002802374100002002402700002402422700002302446700002402469856013102493       2019                        eng d  a1944-824400a[MoS4](2-)-Intercalated NiCo-layered double hydroxide nanospikes: an efficiently synergized material for urine to direct H-2 generation0 aMoS42Intercalated NiColayered double hydroxide nanospikes an eff  cJUL   a25917-259270 v113 a<p>Substituting the energy-uphill water oxidation half-cell with readily oxidizable urea-rich urine, a ground-breaking bridge is constructed, combining the energy-efficient hydrogen generation and environmental 6 protection. Hence, designing a robust multifunctional electrocatalyst is desirable for widespread implementation of this waste to fuel technology. In this context, here, we report a simple tuning of the electrocatalytically favorable characteristics of NiCo-layered double hydroxide by introducing [MoS4]2- in its interlayer space. The [MoS4]' insertion as well as its effect on the electronic structure tuning is thoroughly studied via X-ray photoelectron spectroscopy in combination with electrochemical analysis. This insertion induces overall electronic structure tuning of the hydroxide layer in such a way that the designed catalyst exhibited favorable kinetics toward all the required reactions of hydrogen generation. This is why our homemade catalyst, when utilized both as a cathode and anode to fabricate a urea electrolyzer, required a mere X1.37 V cell potential to generate sufficient H2 by reaching the benchmark 10 mA cm-2 in 1 M KOH/0.33 M urea along with long-lasting catalytic efficiency. Other indispensable reason of selecting [MoS4]2- is its high-valent nature making the catalyst highly selective and insensitive to common catalyst-poisoning toxins of urine. This is experimentally supported by performing the real urine electrolysis, where the nanospike-covered Ni foam-based catalyst showed a performance similar to that of synthetic urea, offering its industrial value. Other intuition of selecting [MoS4]2- was to provide a ligand-based mechanism for hydrogen evolution half-cell [hydrogen evolution reaction (HER)] to preclude the HER-competing oxygen reduction. Another crucial point of our work is its potential to avoid the mixing of two explosive product gases, that is, H2 and O-2.</p>
10ahydrogen evolution reaction10aLayered double hydroxide10anickel oxyhydroxide10asewage denitrification10aurea oxidation reaction10aurine/urea electrolysis1 aNadeema, Ayasha1 aKashyap, Varchaswal1 aGururaj, Rakshitha1 aKurungot, Sreekumar  uhttps://library.ncl.res.in/content/mos42-intercalated-nico-layered-double-hydroxide-nanospikes-efficiently-synergized-material02194nas a2200241   4500008004100000022001400041245016800055210006900223260000800292300001400300490000600314520127100320653002201591653002401613653002601637653003201663653003001695100002001725700003001745700002701775700002401802856012601826       2020                        eng d  a2196-021600aCo@CoAl-layered double hydroxide/nitrogen-doped graphene composite catalyst for Al-H2O-based batteries: simultaneous hydrogen production and electricity generation0 aCoCoAllayered double hydroxidenitrogendoped graphene composite c  cJUN  a2582-25910 v73 a<p>Currently, the low energy efficiency of water electrolysis has compelled research toward the development of novel and energy-effective strategies for low-cost H-2 generation. In this context, we report a new concept of simultaneous H-2 and electricity generation by separating out the exothermic self-sustained Al-H2O reaction via electrochemistry. In addition, to catalyze the cathodic water reduction reaction, a single-pot and environmentally benign synthesis method is adopted. It results in the design of an electrocatalyst composed of Co@CoAl-layered double hydroxide core-shell nanospheres anchored over in situ generated N-doped graphene. Toward the water reduction reaction, the designed catalyst shows a negative voltage shift of mere around 113 mV with respect to the commercial Pt/C catalyst to reach the benchmark 10 mA cm(-2), with excellent stability of approximately 86 % voltage retention after 12 h of continuous operation. The catalytic superiority of our material is evident when taken for battery-level testing; the fabricated device was able to deliver an average output voltage of around 0.95 V at a discharge current density of 5 mA cm(-2) along with H-2 liberation, which was also detected and quantified through gas chromatography.</p>
10aAl-H2O fuel cells10achronopotentiometry10acore-shell structures10ahydrogen evolution reaction10alayered double hydroxides1 aNadeema, Ayasha1 aKharabe, Geeta, Pandurang1 aBiswal, Dibya, Prakash1 aKurungot, Sreekumar  uhttps://library.ncl.res.in/content/cocoal-layered-double-hydroxidenitrogen-doped-graphene-composite-catalyst-al-h2o-based