Carbon dioxide adsorption and conversion to methane and ethane on hydrogen boride sheets

Hydrogen boride (HB) sheets are metal-free two-dimensional materials comprising boron and hydrogen in a 1:1 stoichiometric ratio. In spite of the several advancements, the fundamental interactions between HB sheets and discrete molecules remain unclear. Here, we report the adsorption of CO 2 and its conversion to CH 4 and C 2 H 6 using hydrogen-deficient HB sheets. Although fresh HB sheets did not adsorb CO 2 , hydrogen-deficient HB sheets reproducibly physisorbed CO 2 at 297 K. The adsorption followed the Langmuir model with a saturation coverage of 2.4 × 10 −4 mol g −1 and a heat of adsorption of approximately 20 kJ mol −1 , which was supported by density functional theory calculations. When heated in a CO 2 atmosphere, hydrogen-deficient HB began reacting with CO 2 at 423 K. The detection of CH 4 and C 2 H 6 as CO 2 reaction products in a moist atmosphere indicated that hydrogen-deficient HB promotes C–C coupling and CO 2 conversion reactions. Our findings highlight the application potential of HB sheets as catalysts for CO 2 conversion. Boron-containing materials have experimentally and theoretically been shown to be promising materials for CO 2 capture and conversion. Here, hydrogen-deficient 2D hydrogen boride sheets are shown to physisorb CO 2 and promote conversion to methane and ethane.