Highly effective Pd/ZSM-12 bifunctional catalysts by in-situ glow discharge plasma reduction: the effect of metal function on the catalytic performance for n-hexadecane hydroisomerization

•The effective xPd/Z12-E bifunctional catalysts are prepared by in-situ glow-discharge plasma reduction.•Pd nanoparticles in xPd/Z12-E have higher Pd dispersion, as well as more Pd (111) facets.•The synergistic effect of the larger CPd/CH+ ratio and the stronger metal function enhanced catalytic performance.•ZSM-12 with 12-ring pore structure is conducive to the formation of multi-branched isomers.•xPd/Z12-E catalysts show higher iso-hexadecane yield and excellent catalytic stability in the n-hexadecane hydroisomerization.