The Synthesis Of Carbon Based Nano-composites And Their Applications In The Hydrolytic Dehydrogenation Of Ammonia Borane

Nanomaterials have been shown to be important for the future life. Carbon based nanomaterials such as carbon nanotubes and graphene have got a lot of research interest due to their excellent properties including optical, electrical, mechanical properties. The combination of metal nanoparticles and carbon materials can also be used to improve the catalytic properties of the composites, which has been fully verified in many domains. Because of the interfacial interaction between carbon materials and metal nanoparticles, the composites could be highly efficient and stable catalysts for the hydrolysis of ammonia borane(AB). Synchrotron radiation techniques as effective tools to analyze the electronic structure can help to explore the catalytic mechanism in the hydrolysis of AB.In this paper, we have successfully prepared the hybrid materials of carbon nanotubes(or graphene oxide) and metal, and applied them in the hydrolysis of AB. we also used synchrotron radiation techniques to understand the relationship between the catalytic activity and the electronic structure of materials for high efficiency catalysts. The results have been illustrated as below:First, we prepared non-noble metal nano-catalysts loaded inside and outside of carbon nanotubes(CNTs) by a wet chemical method. We found a strong synergistic effect between cobalt and nickel, which improve the performance of CoNi-in-CNTs. Unfortunately the tube structure of carbon nanotubes doesn’t help to immobilize the nanoparticles and the stability of the hybrids is not good enough. At the same time, we also synthesis PdRh-GO composite for catalyzing AB.Then we used graphene oxide(GO) to load non-noble metal NPs for better performance. The hybrids of M-GO(M=Ni, Co, NiCo) have been prepared by a facile method and show good catalytic property in the hydrolysis of AB. STXM has been used to investigate the electronic structure of the hybrids. Metal elements can be imaged with a uniform dispersion on GO. The XANES spectra suggest that Ni in Ni-GO shows a low chemical state similar to Ni metal while Ni in NiCo-GO shows an oxidized state with high performance. An apparent feature peak A1 can be observed from the XANES spectra of the C K-edge of the M-GO compound, which represents the interaction between different metals and GO. It can be related to the catalytic performance of hybrids.Finally, we prepared N-doped GO with Pt, Ni deposited on the carbon based substrate. The hybrids were labeled as M-NGO(M=Pt, Ni, Pt3Ni7, Pt5Ni5, Pt7Ni3). We synthesized Pt3Ni7-GO as a control. The TEM figures showed that metal nanoparticles were loaded on NGO uniformly with a much smaller size than that of Pt3Ni7-GO. As a result, it possessed a much better performance than Pt3Ni7-GO. In addition, the XANES and XAFS results revealed that an interfacial interaction between metal and the NGO substrate, which might be responsible for the enhanced performance. The Pt3Ni7-NGO sample showed excellent catalytic property in the hydrolysis of AB, which exhibited a top TOF value of 709.56(H2) mol/(Cat-Pt)mol·min ever reported for Pt based catalysts.