Light-driven Low-temperature Dry Reforming of Methane over Carbon-tuned Ni/CeO2 Catalysts

Abstract: Light-driven photothermal dry reforming of methane (DRM) offers a promising route to convert two greenhouse gases into valuable syngas, yet the development of catalysts that simultaneously achieving strong light absorption, efficient photothermal conversion and high DRM activity at low temperatures remains a grand challenge. Here we reported a carbon-tuned Ni/CeO2 catalyst that achieved exceptional photothermal DRM performance through the modification of graphite carbon. By simply varying the calcination temperature under an Ar atmosphere, the carbon configuration evolved from amorphous to graphitic, with the optimally Ni(750Ar-H)/CeO2 catalyst delivering remarkable H2 and CO production rates of 3546.1 and 5496.4 mmol·g-1 cat.·h-1 at a surface temperature of only 479 °C, attaining a high light-to-fuel efficiency of 41.3%. Structural characterizations showed that graphitic carbon not only narrowed the catalyst band gap and enhanced visible-light absorption but also facilitated charge separation and boosted photothermal conversion. Mechanistic studies revealed that graphitic carbon promoted oxygen vacancy formation, modulated metal-support interactions and established an efficient surface reaction pathway involving oxygen-containing intermediates. Our findings establish carbon speciation engineering as a powerful strategy to enhance photothermal DRM performance at a low reaction temperature.