Highly efficient solar-driven CO₂ reforming of methane via concave foam reactors

Solar-driven CO₂ reforming of methane into value-added syngas is promising to solve global climate change and energy crisis problems simultaneously. However, there remains a large gap between currently reported solar-to-fuel efficiency and the theoretical limit. Here, we proposed an alternative way to enhance solar-driven CO₂ reforming of methane performances by shaping foam reactors into concave geometries. By coupling solar radiation transport, fluid-solid coupling heat transfer, thermochemical kinetics, non-isothermal flow and mass transfer, a numerical analysis model is built. For the uniform planar reactor, multi-parameter optimization of porosity, pore diameter, and reactor length is conducted through a multi-island genetic algorithm, and the optimized solar-to-fuel efficiency achieves as high as 50.4%. By shaping planar foam reactors into parabolic concave geometries, the solar-to-fuel efficiency further increases 53.3%, the efficiency is increased by 21.97% compared with the reactor without multi-parameter optimization. This superior performance can be attributed to more uniform and appropriate temperature distribution, which makes major reactant components react within a higher temperature range above 1000 K. This work provides alternative routes for designing high-performance porous foam reactors and achieving highly efficient solar-driven CO₂ reforming of methane.