Dry reforming of methane (DRM) is a widely studied method for converting carbon dioxide (CO 2 ) and methane (CH 4 ) into syngas. Traditionally, this reaction operates with a CO 2 /CH 4 feed ratio of 1. However, future feedstocks—such as CO 2 -rich natural gas—are expected to contain much higher concentrations of CO 2 , requiring costly separation processes to achieve the desired CH 4 .
In a study published in Nature Chemistry , a team led by Profs. WANG Guoxiong, XIAO Jianping, and BAO Xinhe from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences developed a novel process for the direct production of syngas via super-dry reforming of methane (CO 2 /CH 4 ≥ 2), and offered a promising way for efficient and direct utilization of CO 2 -rich natural gas using high-temperature tandem electro-thermocatalysis based on solid oxide electrolysis cells (SOECs).
Operating at 600 to 850 °C, SOECs are capable of converting CO 2 and H 2 O into CO and H 2 . With high reaction rates, high energy efficiency, and low operating costs, they have great potential for CO 2 utilization, hydrogen production, and renewable energy storage. Considering the similar temperature range of SOECs and DRM, researchers developed a novel process that coupled DRM, reverse water-gas shift (RWGS), and H 2 O electrolysis at the SOEC cathode.
In this setup, the in situ electrochemical reduction of H 2 O byproduct generates H 2 and O 2- ions. These O 2- ions then migrate through the electrolyte and are electrochemically oxidized to O 2 at the anode under an applied potential. This process drives the RWGS equilibrium forward, enhancing CO 2 conversion and H 2 selectivity beyond conventional thermodynamic limitations.
Moreover, researcher in suit exsolved Rh nanoparticles onto a CeO 2-x support, creating high-density Ce 3+ -V O -Rh δ+ interfacial active sites. When operating at a CO 2 /CH 4 ratio of 4, the system achieved CH 4 conversion of 94.5% and CO 2 conversion of 95.0%, with nearly 100% selectivity toward CO and H 2 . The apparent methane reducibility reached the theoretical maximum of 4.0.
Further investigation revealed that Rh δ+ sites are primarily responsible for CH 4 dissociation, while the Ce 3+ -V O -Rh δ+ interface—rich in oxygen vacancies—promotes CO 2 adsorption, activation, and the RWGS reaction. This same interface also catalyzed electrochemical H 2 O reduction, boosting both CO 2 conversion and H 2 selectivity.
"Our study may open a new avenue for the direct utilization of CO 2 -rich natural gas and industrial tail gases using renewable energy," said Prof. WANG.
Nature Chemistry
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Super-dry reforming of methane using a tandem electro-thermocatalytic system
21-Mar-2025