Light-Driven Metal Exsolution-Redissolution of High-Entropy Oxide Enabling High-Performance Dry Reforming of Methane

Solar-driven dry reforming of methane (DRM) is attractive for syngas production as an energy-efficient and environmentally friendly process. However, the remaining challenges of low yield and coke-induced inability in this route severely limit its applicability. Here, a light-induced metal exsolution-dissolution strategy is reported using high-entropy oxide (HEO) as a support for highly active and durable photothermal DRM. As evidenced by structural characterizations and theoretical simulations, the metal exsolution-dissolution process triggers the chemical looping of oxygen vacancies on HEO, in which CH₄ is activated to CO and H₂ by lattice oxygen while oxygen from CO₂ can fill the oxygen vacancy and release CO. Such a pathway greatly improves product formation and coking resistance, overcoming the limitations. As a result, the optimized CoNiFeZnCr-HEO supported Rh nanocomposite achieves a high H₂/CO production of 0.242/0.246 mol g^-1 h^-1 with a balance selectivity of 0.98 and impressive long-term stability (200 h). The yield is ≈300 and 450 times higher than that of quaternary and ternary oxides-based catalysts, respectively. This work paves the way for new insights into the light-driven DRM process and highlights the integration of dynamic surface evolution with molecular activation to enhance catalytic performance.