Transition Metal Nanoparticles-Carbon Nitride Nanotube Hybrids: Direct Hydrogen Generation Catalyst of Chemical Hydride Aqueous Solution

전이금속-카본나이트라이드 나노튜브 혼성체: 화학적 수소화물 수용액의 수소발생 촉매

We demonstrate that trasition metal catalyst nanoparticle (NP) attached to carbon nitride nanotubes (CNNTs) show selective catalytic activities on hydrogen generation from the water solution including chemical hydride negative ions. The natural bonding orbitals (NBO) obtained from the first-principle calculations shows that the catalysts attached on CNNTs are quite differently polarized when they play for hydrogen generation from chemical hydride ions and hydrogen of water. For Co and Ni nanoparticles attached on CNNTs, their charges are more positively polarized when they interact with $BH_4^-Na^+$ and $H_2O$ while Pt atoms are less positively charged. In this matter, the increased positive charges on catlyst nanoparticles are proven to be more efficient in attracting hydride negative ions, thus improving hydrogen generate rates. Consequently, this result implies that these different charge polarization leads to selective catalytic activities of NPs-CNNTs. In the hydrogen generation experiments, Co-CNNTs shows the highest hydrogen generation rate when the similar amounts of catalyst nanoparticles (Co, Ni, and Pt) are dispersed on the sidewalls of CNNTs.