The controlled synthesis of metal-acid bifunctional catalysts: The effect of metal:acid ratio and metal-acid proximity in Pt silica-alumina catalysts for n-heptane isomerization

•Optimal proximity between metal and acid sites for bifunctional behavior is nanometer or micrometer scale and not atomic scale.•Each metal site supplies hundreds of acid sites.•The control of metal:acid ratio and metal-acid proximity can be controlled by simple syntheses.