Remarkable uptake of CO2 and CH4 by graphene-Like borocarbonitrides, BxCyNz.

ABSTRACT

The surface areas and uptake of CO(2) and CH(4) by four graphene samples are measured and compared with activated charcoal. The surface areas are in the range of 5-640 m(2) g(-1), whereas the CO(2) and CH(4) uptake values are in the range of 18-45 wt % (at 195 K, 0.1 MPa) and 0-2.8 wt % (at 273 K, 5 MPa), respectively. The CO(2) and CH(4) uptake values of the graphene samples vary linearly with the surface area. In contrast, graphene-like B(x)C(y)N(z) samples with compositions close to BC(2)N exhibit surface areas in the range of 1500-1990 m(2) g(-1) and CO(2) and CH(4) uptake values in the ranges 97-128 wt % (at 195 K, 0.1 MPa) and 7.5-17.3 wt %, respectively. The uptake of these gases varies exponentially with the surface area of the B(x)C(y)Z(n) samples, and the uptake of CH(4) varies proportionally with that of CO(2). The uptake of CO(2) for the best BC(2)N sample is 64 wt % at 298 K. The large uptake of both CO(2) and CH(4) gases by BC(2)N betters the performance of graphenes and activated charcoal. First-principles calculations show that the adsorption of CO(2) and CH(4) is more favored on BCN samples compared to graphene.