Shielded bifunctional nanoreactor enabled tandem catalysis for plasma methane coupling
2025-05-17
The direct conversion of methane into valuable unsaturated C 2 hydrocarbons (C 2 H 2 and C 2 H 4 ) attracts growing attention. Non-thermal plasma offers a promising approach for this process under mild conditions. However, the competing formation of C 2 H 6 and excessive dehydrogenation limit the selectivity toward C 2 H 2 and C 2 H 4 . Herein, we develop a promising shielded bifunctional nanoreactor with a hollow structure and mesoporous channels (Na 2 WO 4 -Mn 3 O 4 /m-SiO 2 ) that effectively limits CH 4 overactivation and promotes selective coupling to form C 2 H 2 and C 2 H 4 under plasma activation, achieving 39% CH 4 conversion with 42.3% C 2 H 2 and C 2 H 4 fraction. This nanoreactor features isolated Na 2 WO 4 embedded within the channels and Mn 3 O 4 confined in the cavity of the SiO 2 hollow nanospheres, enabling internal tandem catalysis at co-located active sites. Na 2 WO 4 induces the conversion of diffused CH 4 and CH 3 into reactive intermediates ( * CH and * CH 2 ), which subsequently couple on the Mn 3 O 4 surface to form C 2 H 2 and C 2 H 4 . Furthermore, the mesoporous channels inhibit the plasma discharge within the nanoreactor, preventing deep dehydrogenation of CH x species to solid carbon. This nanoreactor demonstrates a highly selective route for the nonoxidative conversion of methane to valuable C 2 hydrocarbons, offering a new paradigm for the rational design of catalysts for plasma-driven chemical processes.