Preparation and methane adsorption of two-dimensional carbide Ti2C

Abstract

Here a novel material for methane adsorption was synthesized and studied, which is a graphene-like two-dimensional (2D) carbide (Ti2C, a member of MXenes), formed by exfoliating Ti2AlC powders in a solution of lithium fluoride (LiF) and hydrochloric acid (HCl) at 40 °C for 48 h. Based on first-principles calculation, theoretically perfect Ti2C with O termination has a specific surface area (SSA) of 671 m2 g−1 and methane storage capacity is 22.9 wt%. Experimentally, 2.85 % exfoliated Ti2C with mesopores shown methane capacity of 11.58 cm3 (STP: 0 °C, 1 bar) g−1 (0.82 wt%) under 5 MPa and the SSA was 19.1 m2 g−1. For Ti2C sample intercalated with NH3·H2O, the adsorbed amount was increased to 16.81 cm3 (STP) g−1 at same temperature. At the temperature of 323 K, the adsorbed amount of as-prepared Ti2C was increased to 52.76 cm3 (STP) g−1. For fully exfoliated Ti2C, the methane capacity was supposed to be 28.8 wt% or 1148 V (STP)v−1. Ti2C theoretically has much larger volume methane capacity than current methane storage materials, though its SSA is not very high.