Au–Pd Tandem Photocatalysis for Nonoxidative Coupling of Methane toward Ethylene

Abstract

Photocatalytic nonoxidative coupling of CH 4 to C 2 H 4 with a high rate and selectivity is considered challenging and impractical due to complex chemical pathways and unfavorable thermodynamics. This work introduces a strategy of tandem photocatalysis based on Au and Pd nanoparticles codeposited on a Bi 2 NbO 5 F photocatalyst, which divides the CH 4 to C 2 H 4 reaction into two distinct steps carried out in tandem by multiple activity components, i.e., CH 4 coupling to C 2 H 6 on Au and C 2 H 6 dehydrogenation on Pd. As a result, the optimized Au–Pd/Bi 2 NbO 5 F shows CH 4 coupling to C 2 H 4 with a high yield of 22.6 μmol g –1 h –1 and selectivity of 63% under simulated solar light irradiation. The reaction pathway is investigated by a series of activity experiments and in situ characterizations, demonstrating separate steps on Au and Pd. This work proposes a general strategy for the future design of photocatalysts to drive complex reactions efficiently and selectively based on the concept of a tandem system.