**2.2. Catalysts characterization**

Physical adsorption of gases (N2 at 77 K and CO2 at 273 K) and mercury porosimetry were used to determine the pore volume distribution and the specific surface area for both supports and the specific surface area [16]. Both adsorptives (N2 and CO2) allow estimating the pore volume distribution for pores with a diameter up to 7.5 nm approximately. From Dubinin-Radushkevich equation to the CO2 isotherm at 273 K, it is possible to obtain the micropore volume (*V*micro), while the supermicropore volume (*V*sm) is attained by the subtraction of *V*micro to the volume calculated by the same equation but applied to the N2 adsorption isotherm at 77 K. By mercury porosimetry using a Carlo Erba 2000 equipment, macropore volume (*V*macro) and part of the mesopore volume (*V*meso) were determined. The rest of *V*meso was obtained from N2 adsorption isotherm and Hg porosimetry as described previously [17].

Using ICP Perkin Elmer equipment, metal loadings of the catalysts were measured.

Micromeritics AutoChem II 2920 was used to determine the H2 chemisorption of Pd at 303 K using 0.2 g of catalyst. *In situ* sample reduction was performed using a H2/Ar stream (5% v/v), ensuring the absence of beta-phase palladium hydride on the catalyst surface. The samples were degassed *in situ* for 2 h in an argon flow (AGA purity of 99.99%) and cooled up to 303 K. Then, the hydrogen uptake was measured by sending calibrated pulses. The metal dispersion was calculated assuming a H:Pd = 1 stoichiometry [18].

Temperature programmed reduction, TPR, of the samples was performed using a Micromeritics AutoChem II 2920. Gamma-alumina-supported catalysts were pretreated for 30 min at 673 K under an O2 stream, and cooled with an Ar stream (AGA purity of 99.99%). The palladium anchored on GF-45 was pretreated with an argon flow at the same operational conditions used for alumina-based catalysts. The TPR profiles were obtained increasing the temperature up to 1223 K at 10 K min−1 in a 5% (v/v) hydrogen/argon stream.

Electronic states of Pd, Cl or N were measured using a VG Microtech Multilab equipment following a procedure elsewhere published [19]. The reference-binding energies (BEs) were Al 2p at 74.4 eV and C 1s peak at 284.5 eV for alumina and carbonaceous catalysts, respectively.
