High coking resistance of Ni/A2Ti2O7 catalysts via modulating the A site of A2Ti2O7 (A = La, Gd) for dry reforming of methane

Abstract

Ni based catalysts are currently the most investigated for dry reforming of methane (DRM) due to the advantages in intrinsic activity and cost. However, due to carbon deposition, the questionable durability greatly limits its practical application in the industry. Herein, Gd-doped Ni-La2Ti2O7 and La-doped Ni-Gd2Ti2O7 catalysts were prepared by modulating the A site of the A2Ti2O7 structure. Moderate A site doping tunes the electronic properties of the A2Ti2O7, which would not only significantly enhance the activation ability of C–H bonds of CH4, but also enhance the adsorption capacity of CO2, ultimately affecting the catalytic performance of Ni/A2Ti2O7 for the DRM. Among the modified catalysts, 2 % Gd doped Ni-La2Ti2O7 exhibited excellent stability and maintained CH4 and CO2 conversion at 70.8 % and 86.6 %, respectively, for 200 h at 800 °C with negligible carbon deposition. The fundamental reason for A site doping is that it can make the catalyst produce more surface adsorbed oxygen species, which could accelerate the elimination of deposited carbon.