(628b) Ti3C2Tx and Nb2CTx Mxenes As Ni Catalyst Support in Dry Reforming of Methane

The development of efficient catalysts for dry reforming of methane (DRM) is critical for the sustainable production of syngas, an essential precursor for many industrial processes. DRM is known to have a high energy penalty due to the intrinsic chemical stability of the CO₂ molecule. In this work, we explore the use of MXene (Ti₃C₂T_x and Nb₂CT_x) as support for Ni catalysts to address their low sintering resistance during DRM. MXenes are a new family of layered and porous two-dimensional materials with exceptional properties that can be harnessed in catalysis. The layered structure allows the catalyst to be intercalated with the sheets and anchored. Ni is low-cost, possesses good activity at relatively mild reaction conditions, and is naturally abundant enough to facilitate scalability to industrial applications. The MXenes were etched using NH₄HF₂. Wet impregnation was used to synthesize MXene-supported Ni catalysts (Ni/MXene) and a reference catalyst (Ni/SiO₂) with about 10 wt% loadings, determined by ICP-MS. The catalysts were evaluated during DRM at a space velocity of 90,000 ml/g_cat.hr, 700°C, 1:1 feed ratio, atmospheric pressure and H₂ pre-reduction at 500°C. After reaction at 20 h TOS, the average apparent CH₄ reaction rate was 100.7 ± 10.4 and 104.5 ± 13.8 mmol/g_Ni.min for Ni/Ti₃C₂T_x and Ni/Nb₂CT_x respectively. The average apparent CO₂ reaction rate was 47.57 ± 16.2 and 88.78 ± 35.3 mmol/g_Ni.min for Ni/Ti₃C₂T_x and Ni/Nb₂CT_x respectively. The average H₂/CO ratio over 20 h TOS was 0.59 and 0.45 for Ni/Ti₃C₂T_x and Ni/Nb₂CT_x respectively. The dry reforming performance for the Ni/MXene was superior to Ni/SiO₂ in terms of methane reaction rate, syngas quality, and syngas yield. The degree of graphitization of the deposited coke, as revealed by the G- to D-band ratio in their Raman spectra, was high in the MXene-based catalysts in the range of 1.2-3.4.