Built-in tandem catalysis in hierarchical pores for efficient vinyl chloride production.

Tandem catalysis over disparate active sites is frequently designed to promote the catalytic efficiency for industrial reactions. Herein, a built-in tandem system in a single hierarchical porous catalyst is constructed for vinyl chloride production from ethylene dichloride and acetylene cascade. Using a pore-selective filling strategy, Ru, CuRu, and AuRu components are sequentially confined in the macro-, meso- and micropores of carbon material. Mechanism study shows that ethylene-dichloride dehydrochlorination occurs on macropore Ru sites, generating vinyl chloride. H and Cl radicals react with acetylene on mesopore CuRu sites, and the residual acetylene is hydrochlorinated over micropore AuRu sites. The stronger acetylene adsorption of CuRu and AuRu in a VCM-rich atmosphere enables acetylene conversion near the thermodynamic limit and stable operation for 1200 h on stream. This built-in tandem catalysis in hierarchical pores provides a general paradigm for cascade reactions in a single porous catalyst.