Strategies for enhancing hydrogen storage capacity of carbon-based sandwich material by boron doping: Exploring the optimal doping ratio

In order to research the influence of boron doping on hydrogen storage capacity of Sc3-(C6H6)2, we systematically studied the hydrogen storage behavior of sandwich material theoretically using density functional theory (DFT) computation at Perdew-Burke-Ernzerhof (PBE) method. All of the pure and boron doped Sc3-(C6H6)2 optimization and hydrogen storage data were obtained by our group using Gaussian 16 software. Due to the lower gravimetric density required by the US Department of Energy (DOE), the pure carbon-based sandwich Sc3- (C6H6)2 is not desirable medium for hydrogen storage. When the boron atoms doped (1-12), the corresponding gravimetric densities are improved. The boron doping can increase the hydrogen storage capacity of Sc3-(C6H6)2 to the requirements of the US DOE, except for Sc3-C11BH12 and Sc3-C2B10H12. In Sc3-C9B3H12, Sc3-C2B10H12,Sc3- CB11H12, and Sc3-B12H12, some hydrogen molecules will automatically dissociate and form stable chemical bonds with B or Sc atoms in the boron doping materials. Different analysis methods indicate that Sc3-C10B2H12, Sc3- C8B4H12,Sc3-C7B5H12, Sc3-C6B6H12, Sc3-C5B7H12, Sc3-C4B8H12, and Sc3-C3B9H12 have excellent performance in hydrogen storage. Obviously, the boron doped Sc3-(C6H6)2 with B:C doping ratio of 1:1 has the maximum hydrogen storage capacity.