Co Mo B nanoparticles supported on foam Ni as efficient catalysts for hydrogen generation from hydrolysis of ammonia borane solution

Real-time tunable hydrogen generation from hydrolysis of borohydrides using 3D magnetic catalysts

“…59 The Mo 3d region detected peaks at 231.98 eV and 235.28 eV, indicating the presence of Mo 6+ of MoO 3 on the catalyst surface. 61 According to previous studies, MoO 3 contributes to the generation of oxygen vacancies, which can significantly improve the catalytic activity (Fig. S3 †), since oxygen vacancies in the oxide facilitate the dissociation of water, which is the rate-controlling step of the hydrolysis reaction of NaBH 4 .…”

“…The elemental boron peak is positively shifted by about 0.7 eV compared to that of pure boron (187.0 eV), and this shift is due to the electron transfer from the B atom to Co atom, which is a typical phenomenon of amorphous transition metal borides, 64 and the electron-enriched Co active sites are able to accelerate the NaBH 4 dissociation. 65 The O 1s peaks of the as-prepared Co–Mo–O–B/MF are fitted at 531.7 eV and 530.6 eV, corresponding to the majority content of hydroxides and minority content of oxides, respectively. 66 The XPS Co 2p spectrum and O 1s spectrum verified that Co was mainly present in the form of CoO/Co(OH) 2 on the surface of the catalyst, which may be attributed to inevitable oxidation of elemental cobalt on the surface during preparation, drying and testing.…”

Rational 3D Structure of Monolithic Catalysts for Enhanced Hydrolytic Dehydrogenation of Ammonia Borane

“…74 To sum up, as for the unmodified CoMoB active layer, element B acts as an electron donor to generate electron-rich Co, and Mo provides a small amount of oxygen vacancies in the form of high-valent oxides, which plays as electron promoter to transfer electrons to surface Co atoms. 75,76 By further electrochemical modification, the introduction of Fe elements intensifies the electron enrichment of Co, and a large number of Co and O vacancies are introduced through the directional migration of atoms. 77 The above increases the number of catalytic active sites and electronic modulation of metallic sites (Co), 78 and the effective kinetic activation of H 2 O on the electron-rich Co allows an easier dissociation into OH and H, which is the ratedetermining step of a reaction step of AB hydrolysis.…”

“…The apparent peak attributable to the Co–O scattering path in the Fe-CoMoB active layer demonstrates the oxidation effect during the modification process, and the decreased amplitude of the Co–Co and Co–Mo paths indicate the appearance of Co site defects. , The EXAFS fitting analysis at the Co K-edge indicates the decreasing of the Co coordination number in Fe-CoMoB compared with CoMoB, which further demonstrates that the electrochemical modification induces multiple Co vacancy sites (Table S2). To sum up, as for the unmodified CoMoB active layer, element B acts as an electron donor to generate electron-rich Co, and Mo provides a small amount of oxygen vacancies in the form of high-valent oxides, which plays as electron promoter to transfer electrons to surface Co atoms. , By further electrochemical modification, the introduction of Fe elements intensifies the electron enrichment of Co, and a large number of Co and O vacancies are introduced through the directional migration of atoms . The above increases the number of catalytic active sites and electronic modulation of metallic sites (Co), and the effective kinetic activation of H 2 O on the electron-rich Co allows an easier dissociation into OH and H, which is the rate-determining step of a reaction step of AB hydrolysis. , The above multilevel synergistic from electron transfer to vacancy generation to micromorphology leads to a significant performance enhancement of the Fe-CoMoB active layer, providing an ∼3-fold catalytic activity in hydrolytic dehydrogenation of AB (Figure S8).…”

PtAuCo Trimetallic Nanoalloys as Highly Efficient Catalysts toward Dehydrogenation of Ammonia Borane

“…The values of the rate constant k at different temperatures were calculated from the slope of the linear part in each plot shown in Figure d. The activation energy was determined as 18.47 kJ/mol according to the corresponding Arrhenius plots, which is lower than most of the reported E a values − for the AB catalytic dehydrogenation reaction, indicating the superior catalytic performance of the as-synthesized Pt 76 Au 12 Co 12 NPs.…”