Absorptive hydrogen scavenging for enhanced aromatics yield during non-oxidative methane dehydroaromatization on Mo/H-ZSM-5 catalysts

The addition of Zr metal particles to MoCx/ZSM-5 in interpellet mixtures (2:1 weight ratio) resulted in maximum single-pass methane conversion of ~27% for dehydroaromatization at 973 K - in significant excess of the equilibrium prescribed ~10% conversion at these conditions - and a concurrent 1.4 - 5.6 fold increase in aromatic product yields due to circumvention of thermodynamic equilibrium limitations by absorptive hydrogen removal by Zr while retaining the cumulative aromatic product selectivity. The absorptive function of the polyfunctional catalyst formulation can be regenerated by thermal treatment in helium flow at 973 K yielding above equilibrium methane conversion in successive regeneration cycles. Hydrogen uptake experiments demonstrate formation of bulk ZrH₁.₇₅ on hydrogen absorption by zirconium at 973 K. Cooperation between absorption and catalytic centers distinct in location and function enables circumvention of persistent thermodynamic challenges in non-oxidative methane dehydrogenation.