The enhanced hydrogen-sensing performance of the Fe-doped MoO3 monolayer: A DFT study

A pure monolayer of orthorhombic MoO3 and Fe-doped MoO3 were constructed to study their hydrogen sensing properties through first-principle density functional theory (DFT) calculations. The results show that Fe can be stably doped into the MoO3 monolayer with a high binding energy of -8.09 eV. Further calculations revealed that pure MoO3 is insensitive to molecular oxygen or hydrogen. However, oxygen can be chemisorbed onto the doped Fe in the modified MoO3 with a high adsorption energy of -0.807 eV, capturing approximately 0.2 e from the sensing material. The introduced hydrogen molecules tended to interact strongly with the pre-adsorbed O-2 molecule to form two H2O, releasing 1.01 e back to the sensing material. There were 1.92 e released back to the MoO3 doped with two Fe atoms during the sensing process which significantly enhancing the hydrogen sensing performance of the modified material. Our study indicates that doping MoO3 with Fe atoms improved its hydrogen sensing performance and is a reasonable way to design effective gas sensing materials. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.