Enhanced reversible hydrogen storage performance of light metal-decorated boron-doped siligene: A DFT study

The use of nanomaterials for hydrogen storage could play a very important role in the large-scale utilization of hydrogen as an energy source. However, nowadays several po-tential hydrogen storage nanomaterials do not have a large gravimetric density and sta-bility at room temperature. In this work, we have investigated the hydrogen storage performances of Na-, K-and Ca-decorated B-doped siligene monolayer (BSiGeML) using density functional theory calculations. The results show that boron doping improves the interaction between the metal adatom and the siligene monolayer (SiGeML). The K-and Ca-decorated BSiGeMLs can bind up to seven H2 molecules per metal adatom, whereas Na-decorated BSiGeML only adsorb four H2 molecules per adsorption site. The effect of tem-perature and pressure on the hydrogen storage capacity of BSiGeMLs was also evaluated. At room temperature, all the H2 molecules adsorbed on Na-, and Ca-decorated BSiGeML are stable at mild pressure. The metal decoration of both sides of BSiGeML may lead tohydrogen gravimetric densities exceeding the target of 5.5 wt% proposed by DOE for the year 2025. K-and Ca-decorated BSiGeML could be efficient hydrogen molecular storage media compared to undoped SiGeML and other 2D pristine materials.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The use of nanomaterials for hydrogen storage is important, but current potential nanomaterials have low density and stability at room temperature. This study investigates the hydrogen storage capabilities of Na-, K- and Ca-decorated B-doped siligene monolayer (BSiGeML) using density functional theory calculations. The results show that boron doping improves the interaction between metal adatoms and the siligene monolayer. K- and Ca-decorated BSiGeML can bind up to seven H2 molecules per metal adatom, while Na-decorated BSiGeML only adsorbs four H2 molecules per site. At room temperature, all H2 molecules adsorbed on Na- and Ca-decorated BSiGeML are stable at mild pressure. Metal decoration on both sides of BSiGeML may exceed the target of 5.5 wt% hydrogen gravimetric density proposed by DOE for 2025. K- and Ca-decorated BSiGeML could be efficient hydrogen molecular storage media compared to undoped SiGeML and other 2D pristine materials.