Solar-driven dry reforming of methane (DRM) offers a milder, more cost-effective, and promising environmentally friendly pathway compared to traditional thermal catalytic DRM. Numerous studies have extensively investigated inexpensive Ni-based catalysts for application in solar-driven DRM. However, these catalysts often suffer from activity loss due to carbon accumulation. In this study, we enhanced the Ni-based catalyst by introducing a secondary cobalt active component. The Al2O3 supporting NiCo alloy catalyst (NiCo/Al2O3), synthesized from layered double hydroxides (LDH), exhibits superior light-absorbing properties. This catalyst demonstrates enhanced resistance to carbon accumulation and greater stability compared to Ni monometallic catalysts in solar-driven DRM. Under the extremely demanding conditions of low light irradiation intensity (1.34 W·cm-2), the yields of H2 and CO from the Ni2Co1/Al2O3 catalysts in DRM were 596.6 and 499.1 μmol·g-1·h-1, respectively. In addition, in the light-assisted thermal-driven catalytic DRM test, the H2 and CO yields of Ni2Co1/Al2O3 catalysts increased by 44.5% and 29.2%, respectively, with the application of only 0.28 W·cm-2 of light irradiation during heating at 350 °C. In situ infrared spectroscopy revealed that the reaction pathways of solar-driven DRM closely resemble those of thermally catalytic DRM, suggesting that the NiCo/Al2O3 absorbed light and converted it into heat and drived the DRM reaction. Furthermore, the in situ infrared spectroscopy tests showed that light irradiation could suppress the reverse water-gas shift reaction. The photothermal catalysts developed in this work provide a green industrial route to the production of DRM.
Keywords: CH4 activation; LDH-based catalysts; NiCo alloy; carbon accumulation; solar-driven DRM.