This review will explore the influences of the active metal, support, promoter, preparation methods, calcination temperature, reducing environment, particle size and reactor choice on catalytic activity and carbon deposition for the dry reforming of methane Bimetallic (Ni−Pt, Ni−Rh, Ni−Ce, Ni−Mo, Ni−Co) and monometallic (Ni) catalysts are preferred for dry reforming compared to noble metals (Rh, Ru and Pt) due to their low-cost Investigation of support materials indicated that ceria−zirconia mixtures, ZrO2 with alkali metals (Mg2+, Ca2+, Y2+) addition, MgO, SBA-15, ZSM-5, CeO2, BaTiO3 and Ca08Sr02TiO3 showed improved catalytic activities and decreased carbon deposition The modifying effects of cerium (Ce), magnesium (Mg) and yttrium (Y) were significant for dry reforming of methane MgO, CeO2 and La2O3 promoters for metal catalysts supported on mesoporous materials had the highest catalyst stability among all the other promoters Preparation methods played an important role in the synthesis of smaller particle size and higher dispersion of active metals Calcination temperature and treatment duration imparted significant changes to the morphology of catalysts as evident by XRD, TPR and XPS Catalyst reduction in different environments (H2, He, H2/He, O2/He, H2−N2 and CH4/O2) indicated that probably the mixture of reducing agents will lead to enhanced catalytic activities Smaller particle size (

Dry reforming of methane: Influence of process parameters—A review

A short review of catalysis for CO2 conversion

The performance of catalysts used for the dry reforming of methane can strongly depend on the selection of active metals, supports and promoters. This work studies their effects on the activity and stability of selected catalysts. Designing an economically viable catalyst that maintains high catalytic activity and stability can be achieved by exploiting the synergic effects of combining noble and/or non-noble metals to form highly active and stable bi- and tri-metallic catalysts. Perovskite type catalysts can also constitute a potent and cost effective substituent. Metal oxide supports with surface Lewis base sites are able to reduce carbon formation and yield a greater stability to the catalyst, while noble metal promoters have proven to increase both catalyst activity and stability. Moreover, a successful metal-support-promoter combination should lead to higher metal-support interacrtion, lower reduction temperature and enhancement of the anti-coking and anti-amalgamation properties of the catalyst. However, the effect of each parameter on the overall performance of the catalyst is usually complex, and the catalyst designer is often faced with a tradeoff between activity, stability and ease of activation. Based on the review carried out on various studies, it is concluded that a catalyst design must take into consideration not only the separate effects of the active metal, support and promoter, but should also include the combined and mutual interactions of these components.

Catalyst design for dry reforming of methane: Analysis review

Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid–base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.

Carbon nanotube catalysts: recent advances in synthesis, characterization and applications.

CO2 reforming of CH4 was carried out over Ni–alumina aerogel catalysts prepared with various Ni loadings. The preparation of alumina supported Ni catalysts via sol–gel synthesis and subsequent supercritical drying led to the formation of very small metal particles, which are evenly distributed over the alumina support. The activity of the aerogel catalysts increased along with increasing metal loading, and eventually, the SAA25 (0.25 in Ni/Al mole ratio) catalyst exhibited the high activity comparable to that of a 5 wt.% Ru/alumina catalyst (ESCAT44, Engelhard). Compared to the alumina-supported Ni catalyst prepared by conventional impregnation method, Ni–alumina aerogel catalysts showed a remarkably low coking rate due to highly dispersed metal particles. From TEM micrograph studies, it was observed that the formation of filamentous carbon was significantly influenced by the metal particle size and proceeded mostly over the metal particles larger than 7 nm. The loss of catalytic activity at 973 K was mainly caused by coke deposition and sintering.

Effect of metal particle size on coking during CO2 reforming of CH4 over Ni–alumina aerogel catalysts

Development of a new photocurable composite resin with reduced curing shrinkage.

A fast sol−gel synthetic route for obtaining alumina aerogels has been developed by modifying the tranditional method under appropriately controlled conditions. The highly mesoporous alumina aerogel prepared by our new sol−gel synthesis method and CO2 supercritical drying had a surface area in excess of 700 m2/g and high thermal stability.

Fast sol-gel synthetic route to high-surface-area alumina aerogels

Characterization of the electrode and electrolyte interfaces of LSGM-based SOFCs

The influences of calcination temperatures and additives for 10 wt.% Cu/γ-Al 2 O 3 catalysts on the surface properties and reactivity for NO reduction by C 3 H 6 in the presence of excess oxygen were investigated. The results of XRD and XPS show that the 10 wt.% Cu/γ-Al 2 O 3 catalysts calcined below 973 K possess highly dispersed surface and bulk CuO phases. The 10 wt.% Cu/γ-Al 2 O 3 and 10 wt.% Mn–10 wt.% Cu/γ-Al 2 O 3 catalysts calcined at 1073 K possess a CuAl 2 O 4 phase with a spinel-type structure. In addition, the 10 wt.% La–10 wt.% Cu/γ-Al 2 O 3 catalyst calcined at 1073 K possesses a bulk CuO phase. The result of NO reduction by C 3 H 6 shows that the CuAl 2 O 4 is a more active phase than the highly dispersed and bulk CuO phase. However, the 10 wt.% Mn–10 wt.% Cu/γ-Al 2 O 3 catalyst calcined at 1073 K possesses significantly lower reactivity for NO reduction than the 10 wt.% Cu/γ-Al 2 O 3 catalyst calcined at 1073 K, although these catalysts possess the same CuAl 2 O 4 phase. The low reactivity for NO reduction for 10 wt.% Mn–10 wt.% Cu/γ-Al 2 O 3 catalyst calcined at 1073 K is attributed to the formation of less active CuAl 2 O 4 phase with high aggregation and preferential promotion of C 3 H 6 combustion to CO x by MnO 2 . The engine dynamometer test for NO reduction shows that the C 3 H 6 is a more effective reducing agent for NO reduction than the C 2 H 5 OH. The maximum reactivity for NO reduction by C 3 H 6 is reached when the NO/C 3 H 6 ratio is one.

Kyung-Lim Kim

Papers

Effect of metal particle size on coking during CO2 reforming of CH4 over Ni–alumina aerogel catalysts

Development of a new photocurable composite resin with reduced curing shrinkage.

Fast sol-gel synthetic route to high-surface-area alumina aerogels

Characterization of the electrode and electrolyte interfaces of LSGM-based SOFCs

Surface properties and reactivity of Cu/γ-Al2O3 catalysts for NO reduction by C3H6: Influences of calcination temperatures and additives