Boron has been explored as p-block
catalysts for nitrogen reduction
reaction (NRR) by density functional theory. Unlike transition metals,
on which the active centers need empty d orbitals to accept the lone-pair
electrons of the nitrogen molecule, the sp3 hybrid orbital
of the boron atom can form B-to-N π-back bonding. This results
in the population of the N–N π* orbital and the concomitant
decrease of the N–N bond order. We demonstrate that the catalytic
activity of boron is highly correlated with the degree of charge transfer
between the boron atom and the substrate. Among the 21 concept-catalysts,
single boron atoms supported on graphene and substituted into h-MoS2 are identified as the most promising NRR catalysts, offering
excellent energy efficiency and selectivity against hydrogen evolution
reaction.
Using the symmetrical, adiabatic, counterflow arrangement, the laminar flame speeds of methane + air and propane + air mixtures, with and without the addition of stoichiometrically small amounts of hydrogen, have been determined by first measuring the flame speeds with stretch and then linearly extrapolating these values to zero stretch. The results show that the flame speed is substantially increased with hydrogen addition, and that it can be linearly correlated with the flame speed without hydrogen addition and a single parameter indicating the extent of hydrogen addition.
A "co-precipitation" method was applied to introduce nanosized Co-and Ni-based catalysts to ammonia borane. It was observed that approximately 1 equiv. of hydrogen was evolved from the doped ammonia borane samples at a temperature as low as 59 °C. Moreover, the catalytic dehydrogenation did not present any induction period, undesirable byproduct borazine, or sample forming. Electron paramagnetic resonance (EPR) characterization revealed that Co in a partially reduced state is the active species in the catalytic dehydrogenation of ammonia borane.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.