Low-temperature oxidative removal of benzene from the air using titanium carbide (MXene)-Supported platinum catalysts

MXenes are an emerging class of two-dimensional (2D) inorganic materials with great potential for versatile applications such as adsorption and catalysis. Here, we describe the synthesis of a platinized titanium carbide MXene (Pt@Ti₃C₂) catalyst with varying amounts of platinum (0.1%-2 wt.%) for the low-temperature oxidation of benzene, an aromatic volatile organic compound often found in industrial flue gas. A 1% formulation of Pt@Ti₃C₂-R allowed near-complete (97%) oxidation of benzene to CO₂ at 225 °C with a steady-state reaction rate (r) of 0.119 mol g^-1·h^-1. This low-temperature catalytic oxidation reaction was promoted by an increase in the lattice oxygen (O*)/Pt²⁺ species (active sites) of 1%Pt@Ti₃C₂-R from 45.3/34.6% to 71.0/61.1% through pre-thermal reduction under H₂ flow, as revealed by X-ray photoelectron spectroscopy, temperature-programmed reduction, and in situ diffuse reflectance infrared Fourier transform spectroscopy analyses. The cataltyic activity of 1% Pt@Ti₃C₂-R against benzene was assessed under the control of the key process variables (e.g., catalyst mass, flow rate, benzene concentration, relative humidity, and time-on-stream) to help optimize the oxidation reaction process. The results provide new insights into the use of platinum-based 2D MXene catalysts for low-temperature oxidative removal of benzene from the air.