Porously hierarchical Cu@Ni cubic-cage microstructure: Very active and durable catalyst for hydrolytically liberating H 2 gas from ammonia borane

Formation of a Key Intermediate Complex Species in Catalytic Hydrolysis of NH3BH3 by Bimetal Clusters: Metal-Dihydride and Boron-Multihydroxy

“…To get over the challenges of cost expensiveness of the noble metal as well as the catalytic limitation of transition metal, the modulation of the noble metal content by alloying with first-row transition metal was considered as a feasible solution, because their active sites could be maintained and their active capabilities could be improved in alloying catalysts. As one expected, most bimetallic catalysts such as Cu(Fe, Ni, Ru) (Rachiero et al, 2011b ; Lu et al, 2013 , 2014 ; Zhang et al, 2016 ), (Pd, Au, Ru)Co (Yan et al, 2010a ; Chen et al, 2011 ; Sun et al, 2011 ; Lu et al, 2012 ; Wang et al, 2012 ), (Au, Ag, Pt, Ru)Ni (Chen et al, 2007 , 2012 ; Yao C. F. et al, 2008 ; Jiang et al, 2010 ), and (Ni, Cu)Pd (Çiftci and Metin, 2014 ; Güngörmez and Metin, 2015 ) have been reported to exhibit the better performance than the monometal catalysts for the hydrogen generation from the hydrolysis of AB. It was deduced that the formations of the heterometallic bonds can adjust the bonding (molecular) orbitals of catalyst surface atoms to reactant with AB and H 2 O molecules.…”

“…To one's expectation, the formations of the Cu-dihydride complexes (IM24 * , IM30 * , and IM35 * ) together with the B-multihydroxy complexes (IM23 * , IM27 * , IM34 * ) can be clearly discerned from the sequential steps in Figures 4B,C . Experimentally, the activation energy for the catalytic hydrolysis of AB dehydrogenation has been conjectured to be the step reaction of B-N bond breaking (Xu and Chandra, 2006 ; Chandra and Xu, 2007 ), where an apparent value was estimated around 0.4 eV for CuNi catalysts (Lu et al, 2014 ; Zhang et al, 2016 ). Our E act = 0.58 eV determined by the highest energy barrier of the reaction path4 at TS113 * state is approach to these experimental activation energies.…”

“…By using the density functional theory (DFT) calculations, herein, we investigate the reaction pathways of H 2 release from the hydrolytic AB and examine the catalytic roles of small NiCu clusters. Experimentally, NiCu bimetallic nanoparticles have been successfully fabricated and the catalytic activity was evaluated in the hydrolytic dehydrogeneration of AB (Lu et al, 2014 ; Zhang et al, 2016 ). The results shown that NiCu bimetallic nanoparticles exhibit the excellent catalytic activity and the low activation energy barriers owning to the charge transfer between Cu and Ni atoms (Lu et al, 2014 ; Zhang et al, 2016 ).…”

“…Experimentally, NiCu bimetallic nanoparticles have been successfully fabricated and the catalytic activity was evaluated in the hydrolytic dehydrogeneration of AB (Lu et al, 2014 ; Zhang et al, 2016 ). The results shown that NiCu bimetallic nanoparticles exhibit the excellent catalytic activity and the low activation energy barriers owning to the charge transfer between Cu and Ni atoms (Lu et al, 2014 ; Zhang et al, 2016 ). Since the dehydrogenation reaction of AB involves an ionic recombination of hydridic H δ− and protic H δ+ , the positively Ni atom would play an attractive role to interact with the [OH] − group by hydrolyzing H 2 O while the negatively Cu atom would act as an agent to accept the hydrolyzed H + ion.…”

TiN nanotube supported Ni catalyst Ni@TiN-NTs: experimental evidence of structure–activity relations in catalytically hydrolyzing ammonia borane for hydrogen evolution

“…[3][4][5][6] Ammonia borane (AB, NH 3 BH 3 ) is a typical representative of chemical hydrogen storage materials with a theoretical hydrogen storage capacity of 19.6 wt%, regarded as the compound with the highest hydrogen content found up to now. 7,8 AB can exist in the solid state under the atmospheric environment, with the unique physicochemical properties such as nontoxicity, incombustiblity, no corrosion and no explosion so on. Moreover, AB can release hydrogen gas (H 2 ) in a controllable manner via catalytic hydrolysis or alcoholysis, which is thus considered as an ideal hydrogen storage medium for fuel cells.…”