Emergence of Si₂BN Monolayer as Efficient HER Catalyst under Co-functionalization Influence

In the present work, we have envisaged the enhancement of hydrogen evolution reaction (HER) activity on stable Si2BN monolayer based on first-principles electronic structure calculations. Herein, we have performed the HER activities on the pristine Si2BN monolayer and various possible active sites on structural defects in the Si2BN monolayer. In addition to the pristine monolayer, we have thoroughly investigated the effect of functionalization and cofunctionalization on the Si2BN monolayer. The adsorption of the most important HER intermediate hydrogen on different possible active sites of Si2BN monolayer has been systematically studied for all the functionalization and cofunctionalization cases. We have determined the projected density of states, work functions, and optical absorption cross-section for all the pristine and doped systems. The charge distributions for all of the monolayer systems are determined along with the mapping of the reaction coordinate based on the hydrogen (H*) adsorption free energies (ΔGH*0). Among all of the functionalized Si2BN monolayers, the C-doped monolayer has been emerged as the active most HER catalyst, whereas in the case of co-functionalization, C–P codoped Si2BN monolayer is the best candidate for HER mechanism.