From the substantial variation in oxygen storage capacity and lability amongst the 3 supports made use of (Table 1). ItNanomaterials 2021, 11,13 ofis apparent from Figure 6a that, though all three catalysts exhibit virtually exactly the same methane consumption rates, the CO2 consumption rates differ Inositol nicotinate Purity appreciably based around the nature from the support. In certain, iridium supported on CZ and ACZ exhibits a substantially greater intrinsic activity compared to Ir/-Al2 O3 , with Ir/CZ becoming all round probably the most active, specifically at reduce temperatures. Additionally, the CO2 consumption apparent activation energies (Ea ) are decrease for the CZ-containing catalysts with Ea decreasing from 91.3 kJ/mol on Ir/-Al2 O3 to 88.5 kJ/mol on Ir/ACZ and to 73.5 kJ/mol on Ir/CZ (Table 2). With regards to the CH4 consumption price, all catalysts exhibited related Ea values of about 92.4 kJ/mol (Figure 6a). This behavior suggests that a bifunctional reaction mechanism requires location, which can be more pronounced on supports with higher oxygen storage capacity (labile lattice oxygen). Especially, surface oxygen vacancies, which are abundant around the ACZ- and CZ-supported catalysts, could activate CO2 by IL-4 Protein References adsorption and disproportionation to CO O. Subsequently regenerated labile oxygen ions could then market the oxidation of carbon deposited on the help and simultaneously raise the oxygen ion spillover onto the Ir particles, producing an [O- , ] helpful double layer on their surface. This benefits in alteration from the electronic state, properties and surface chemistry of Ir nanoparticles by metal-support interactions. The effect of your as-created double layer on the electronic state of noble metal particles has been not too long ago revealed by state-of-the-art XPS measurements on Rh nanoparticle catalysts dispersed on -Al2 O3 – and CZ-containing supports equivalent to those utilised within the present work [6]. It was shown that, beneath DRM conditions, the Rh species existed mostly inside the metallic state (Rh0 ) and also the relative Rh0 content material decreased with decreasing the OSC of the help, following the order Rh/CZ (Rh0 = 100 ) Rh/ACZ (Rh0 = 72 ) Rh/-Al2 O3 (Rh0 = 55 ). It’s affordable to suggest that a qualitatively equivalent effect in the support’s OSC around the electronic state of your dispersed metal is also operable within the case of Ir nanoparticles, thereby favoring their DRM activity when dispersed on CZ-containing supports in comparison to -Al2 O3 . Furthermore, the spillover oxygen species can also act as promoters of your DRM reaction prior to they react with CH4 -derived adsorbed carbonaceous species on Ir internet sites [83]. The CO-enriched syngas produced by Ir/ACZ and Ir/CZ catalysts (Figure 6b) is constant with this interpretation too as with temperature programmed oxidation (TPO) benefits performed over employed catalysts described beneath. The enhanced basicity of ceria-containing supports, which has been proposed to promote the reverse water gas shift reaction [1,2,six,7], may also explain the larger CO content material plus the reduce H2 /CO molar ratio in the reformate, observed for the CZ-containing catalysts.Table 2. Support-induced effects on apparent activation energies and pre-exponential elements of CO2 consumption price during DRM more than Ir/-Al2 O3 , Ir/ACZ and Ir/CZ catalysts. Catalyst Ir/-Al2 O3 Ir/ACZ Ir/CZ Assistance t-OSC ( ol O2 /g) 0 110 557 rCO2 Apparent Activation Energy (Ea ) (kJ/mol) 91.3 0.four 88.5 0.3 73.five 0.two Pre-Exponential Factor ( ro ) CO2 (mol CO2 / gIr ) 4146.4 1.7 3827.six 1.three 645.5 1.Nanomaterials 2021, 11, x FOR.