Trace Pd–Functionalized SnO2 Porous Ceramic for Enhanced Catalytic Combustion of Low-Concentration Methane

The development of advanced catalytic technologies for the combustion of low-concentration methane is crucial for minimizing unburned CH 4 emissions, consequently improving the eco-efficiency of natural gas vehicles and power plants. The integration of effective catalysts into existing systems with minimal modifications is of paramount importance. Porous ceramic composites offer a promising alternative to traditional powder catalysts due to their high surface area, excellent thermal stability, adjustable porosity, and prolonged catalytic durability. This study introduces a trace Pd–incorporated SnO 2 porous ceramic catalyst (Pd/SnO 2 ) fabricated using the spark plasma sintering (SPS) technique. The synthesis process uses a NaCl salt template to create a porous structure and graphite to improve Pd loading and dispersion on the SnO 2 surface. An optimized 10 wt.% graphite-decorated Pd/SnO 2 porous ceramic catalyst, containing a trace Pd loading of 0.17 wt.%, achieved a low T 90 of 427°C during methane reforming tests and maintained stable catalytic performance after multiple temperature cycling and over 900 min of continuous operation. Enhanced activity stems from two synergies: first, graphite-mediated uniform PdO dispersion boosting active site accessibility and second, PdO–SnO 2 interfacial charge transfer generating oxygen-deficient sites, accelerating CH 4 dissociation and stabilizing Pd 2+ against deactivation. These findings highlight the potential of this approach for use in the development of durable and efficient ceramic composite–based catalysts for environmental applications.