Support Induced Effects on the Ir Nanoparticles Activity, Selectivity and Stability Performance under CO2 Reforming of Methane

Abstract

The production of syngas (H2 and CO)—a key building block for the manufacture of liquid energy carriers, ammonia and hydrogen—through the dry (CO2−) reforming of methane (DRM) continues to gain attention in heterogeneous catalysis, renewable energy technologies and sustainable economy. Here we report on the effects of the metal oxide support (γ-Al2O3, alumina-ceria-zirconia (ACZ) and ceria-zirconia (CZ)) on the low-temperature (ca. 500–750 ∘C) DRM activity, selectivity, resistance against carbon deposition and iridium nanoparticles sintering under oxidative thermal aging. A variety of characterization techniques were implemented to provide insight into the factors that determine iridium intrinsic DRM kinetics and stability, including metal-support interactions and physicochemical properties of materials. All Ir/γ-Al2O3, Ir/ACZ and Ir/CZ catalysts have stable DRM performance with time-on-stream, although supports with high oxygen storage capacity (ACZ and CZ) promoted CO2 conversion, yielding CO-enriched syngas. CZ-based supports endow Ir exceptional anti-sintering characteristics. The amount of carbon deposition was small in all catalysts, however decreasing as Ir/γ-Al2O3 > Ir/ACZ > Ir/CZ. The experimental findings are consistent with a bifunctional reaction mechanism involving participation of oxygen vacancies on the support’s surface in CO2 activation and carbon removal, and overall suggest that CZ-supported Ir nanoparticles are promising catalysts for low-temperature dry reforming of methane (LT-DRM).

Selective Catalytic Reduction of NOx over Perovskite-Based Catalysts Using CxHy(Oz), H2 and CO as Reducing Agents—A Review of the Latest Developments

“…The specialized properties of perovskites, such as multiple types of active centers including surface oxygen vacancies, as well as labile lattice oxygen and mobile O 2− ions are particularly useful in catalysis. According to recent discoveries, these properties can play multiple roles as reaction promoters and as stabilizers of dispersed catalyst nanoparticles providing catalysts with high anti-sintering characteristics [ 26 , 27 , 28 , 29 , 30 ].…”

“…However, despite intensive research efforts, such noble metal catalyst formulations, although very efficient in controlling emissions of stoichiometric gasoline engines (TWC conditions), have not been yet as effective as required for the control of non-stoichiometric engines emissions in order to be applicable in the case of lean-burn gasoline and diesel engines or in stationary fossil fuel combustion processes [ 1 , 7 , 13 ]. Bearing in mind that the use of precious metals is also associated with high costs and relatively poor stability, i.e., a propensity to particle agglomeration in the case of hot spots that often occur under real driving conditions (although means and methodologies for stabilizing dispersed catalyst nanoparticles against sintering have recently been discovered [ 26 , 27 , 28 , 29 , 30 ]), significant efforts have been put to the development and use of alternatives such as perovskite derived catalysts, due to their unique physicochemical properties, low cost, and favorable heat stability [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ].…”

The 10th Anniversary of Nanomaterials—Recent Advances in Environmental Nanoscience and Nanotechnology

“…Also known as “nano-catalysts” [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ], they now play a leading role in environmental and energy science and engineering by providing innovative, cost-effective, and durable nanostructured materials with highly promising performance in the control of environmental pollutants, production of clean fuels and added-value chemicals, and circular-economy technologies [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ].…”

“…Indeed, the rational design of materials, particularly at the nano-to-atom level, offers advantages and enables tailoring and fine-tuning of their critical points in catalysis textural, structural, physicochemical, and local surface chemistry properties, as well as the optimization of metal–metal and metal–support interactions, thus resulting in catalytic systems with outstanding activity and stability performance in numerous eco-friendly applications. These include, for example, emission-control catalysis, waste treatment, photocatalysis, bio-refinery, CO 2 utilization and fuel cell applications, as well as hydrocarbon processing for H 2 , added-value chemicals and liquid fuels production [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”

Synthesis and Mathematical Modelling of the Preparation Process of Nickel-Alumina Catalysts with Egg-Shell Structures for Syngas Production via Reforming of Clean Model Biogas

“…Biogas typically consists of CH 4 (50-75%), CO 2 (25-50%) and 2-8% other gases i.e., water vapors (H 2 O), nitrogen (N 2 ), oxygen (O 2 ), and hydrogen sulfide (H 2 S) [6,7]. However, the average composition of CH 4 and CO 2 in a molar ratio equal to 1.5 is favorable for the methane reforming reaction, and furthermore, representative of the biogas produced from many facilities [8,9]. The product of this reaction, synthesis gas or syngas, consisting of hydrogen (H 2 ) and carbon monoxide (CO), is an important industrial raw material, as it can be used for the production of synthetic liquid biofuels and chemicals through the well-known Fischer-Tropsch (FT) process [10][11][12][13][14].…”