NiGa nano-alloy for the dry reforming of methane: Influences of Ga alloying with Ni on the catalytic activity and stability

The massive emission of CO2 and CH4 has caused serious environmental and ecological problems, and dry reforming of methane reaction has received widespread attentions due to the fact that it can eliminate the two gas simultaneously. Herein, Ni60Ga40/Al2O3 (molar ratio of Ni:Ga was 60:40) catalyst was synthesized by mechanochemical synthesis method, offering 75 % CH4 conversion, 85 % CO2 conversion, and H2/CO ratio of 0.93 at 750 °C during 120 h test. Ni in Ni60Ga40/Al2O3 combines with Ga to form Ni3Ga intermetallic compound, which inhibits the sintering of Ni and rapid cracking of CH4. Moreover, the extra Ga species, existing in the form of Ga2O3-Al2O3 with abundant oxygen vacancy, boosts CO2 activation and prevents carbon development on catalyst surface. In contrast, for the pure Ni/Al2O3 and Ga/Al2O3 catalysts, the stability and catalytic activity couldn't be obtained synchronously. This work particularly investigated the CH4 dissociation and CO2 activation for the NiGa/Al2O3 catalysts, establishing the foundation for rational design of low-cost performance catalysts for the dry reforming of methane reactions.