Mesoporous, high-surface-area Cu–Sn mixed-oxide nanorods were fabricated for the first time by nanocasting with the use of mesoporous KIT-6 silica as the hard template. The Cu–Sn nanorods are significantly more active than 1 % Pd/SnO₂ for the oxidation of CO and possesses long-term durability and potent water resistance; they thus have the potential to replace noble metal catalysts for emission-control processes.

Mesoporous Ni-Al₂O₃ catalysts were prepared in one pot following an evaporation-induced self-assembly method (EISA) and used for methane dry reforming. Compared with a traditional Ni/Al₂O₃ catalyst prepared through impregnation method (IMP), the EISA catalysts display significantly improved coke resistance and activity. It is revealed by small-angle XRD (SXRD), N₂ adsorption–desorption, and TEM that an ordered mesoporous structure was formed in the EISA catalysts, which impedes the aggregation of the Ni sites and aids in the mass transfer of the reaction. In addition, the Ni species in the reduced EISA samples more dispersed, more uniformly distributed, and have smaller crystallite size, as evidenced by XRD, H₂ adsorption–desorption, and TEM results. It is speculated that these are the major reasons accounting for the significantly improved dry reforming performance of the EISA catalysts.

La₂Sn₂O₇ and La₂Zr₂O₇, two pyrochlore compounds with different B-site cations, were prepared and used as supports for Ni in methane steam reforming. Compared with Ni/γ-Al₂O₃, both Ni/La₂Zr₂O₇ and Ni/La₂Sn₂O₇ show very stable reaction performance. Whereas Ni/La₂Zr₂O₇ also displays reasonably high activity for the reaction, the activity of Ni/La₂Sn₂O₇ is extremely low. It was found that severe coking occurred with Ni/γ-Al₂O₃, but no coke formation was observed on the two pyrochlore catalysts. On the reduced and spent Ni/La₂Sn₂O₇ catalyst, the Ni₃Sn₂ and Ni₃Sn alloys were detected; these alloys suppressed coke formation but also decreased the activity of the catalyst. In comparison, a large amount of La₂O₂CO₃ was formed on the used Ni/La₂Zr₂O₇ catalyst; these species reacted with the carbon deposits formed on the Ni particles and continuously restored the Ni sites. Thus, coking was effectively suppressed and the initial high activity of the catalyst was maintained. Thus, Ni/La₂Zr₂O₇ is a superior catalyst having the potential for industrial use.

A series of supported Ni–Co/γ-Al₂O₃ bimetallic catalysts with a fixed 12 % Ni loading but different Co contents were prepared by using the coimpregnation method and investigated for methane steam reforming. The addition of Co can significantly improve the coke resistance and the reaction stability of Ni/Al₂O₃ at a mild loss of the reforming activity. XPS and TEM results prove the existence of strong interaction between Ni and Co species. XRD and high-angle annular dark-field scanning transmission electron microscopy mapping results of the reduced catalysts provide direct evidence for surface Ni–Co alloy formation upon Co addition onto Ni/Al₂O₃, which can block part of the active low coordinated Ni sites and lower the metal dispersion, thus effectively suppressing coking and improving the reaction stability in comparison with the unmodified Ni/Al₂O₃ catalyst.

SnO₂/Al₂O₃ supports with different SnO₂ loadings were prepared by using a deposition–precipitation method and characterized by using N₂ and CO adsorption–desorption, XRD, H₂ temperature-programmed reduction, and X-ray photoelectron spectroscopy techniques. SnO₂ dispersed finely on the Al₂O₃ surface with a capacity of 0.172 mmol 100 m⁻², which equals 6.4 % SnO₂ loading. Below this loading, no crystalline SnO₂ can be detected owing to the formation of the sub-monolayer- or monolayer-dispersed SnO₂ phase. Crystalline SnO₂ can be observed only if the SnO₂ loading reaches 9 %. With use of these SnO₂/Al₂O₃ supports, all prepared Pd/SnO₂/Al₂O₃ catalysts demonstrate increased activity compared to Pd/SnO₂ and Pd/Al₂O₃ owing to the presence of more active oxygen species on SnO₂/Al₂O₃ supports as well as their higher surface areas, which improve Pd dispersion. This result indicates that with SnO₂/Al₂O₃ supports, less amount of Pd can be used to obtain catalysts with competitive performance.

Sn-modified Ni/Al₂O₃ catalysts for CH₄ dry reforming were prepared by co-impregnation and two-step impregnation methods and characterized by thermogravimetric analysis with differential scanning calorimetry, SEM, TEM, high-angle annular dark-field scanning transmission electron microscopy mapping, XRD, X-ray photoelectron spectroscopy, H₂ temperature-programmed reduction, and CO₂ temperature-programmed desorption. After reduction, surface Ni-Sn alloys were formed on the Ni particles, which changed the inherent activity of Ni sites and suppressed coking effectively with a mild loss of the activity. The catalysts with different amounts of surface Ni-Sn alloys also provided strong evidence to prove that the coking rate and activity change tendency correlate well with the amount of the surface alloys. These results are of help to develop catalysts with potent resistance to coking for industrial use.

SnO₂-based catalysts modified by La, Ce, and Y with a Sn/Ln (Ln=La, Ce, Y) atomic ratio of 2:1 were prepared by using a co-precipitation method and used for CO and CH₄ oxidation. The catalysts were characterized by N₂ adsorption–desorption, XRD, energy dispersive X-ray spectroscopy (EDS)-SEM, H₂ temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis differential scanning calorimetry (TGA-DSC) techniques. All three rare earth metal oxides were found to improve the thermal stability of SnO₂, which resulted in catalysts with much higher surface areas and smaller crystallite and particle sizes. However, only the addition of Ce resulted in a catalyst with improved activity for both CO and CH₄ oxidation. In contrast, La and Y modification resulted in samples with decreased activity for both reactions. For the Ce-modified sample, Ce cations were found to dope into the lattice of rutile SnO₂ to form a solid-solution structure. As a lattice impurity, ceria, the well-known oxygen storage component (OSC), led to the formation of more defects in the matrix of SnO₂ and impeded the crystallization process, which resulted in a catalyst with a higher surface area and more active oxygen species. In contrast, XRD proved that the addition of La and Y mainly led to the formation of more stable and inert pyrochlore compounds, Sn₂La₂O₇ and Sn₂Y₂O₇, which disrupted a major part of the active sites based on SnO₂. Consequently, the oxidation activity was impaired, although these two samples also have higher surface areas than pure SnO₂. The Ce-modified sample showed not only high activity but also good reaction durability and thermal stability. Furthermore, Sn-Ce binary oxide is a better support than SnO₂, CeO₂, and traditional Al₂O₃ supports for Pd, which gives it the potential to be applied in some real after-treatment applications.

RuO₂/SnO₂ catalysts with 2, 5 and 10 % Ru loadings were prepared with calcined and uncalcined SnO₂ supports by the impregnation method. The catalysts were evaluated for CO and CH₄ oxidation and characterised by N₂-BET, XRD, hydrogen temperature programmed reduction (H₂-TPR), energy-dispersive X-ray spectroscopy scanning electron microscopy (EDS-SEM) and thermogravimetric analysis differential scanning calorimetry (TGA-DSC). Owing to the synergetic effect between RuO₂ and SnO₂, all RuO₂/SnO₂ catalysts are found to be much more active than pure SnO₂ and RuO₂/Al₂O₃ for both CO and CH₄ oxidation. For RuO₂ supported on uncalcined SnO₂, H₂-TPR and TGA-DSC analysis revealed the formation of a new, less active compound between Sn and Ru that consumed active SnO₂ and RuO₂, and could be detrimental to the synergism between RuO₂ and SnO₂, and thus the activity of RuO₂/SnO₂ catalytic system. As a consequence, it is much less active than RuO₂ supported on calcined SnO₂. RuO₂/SnO₂ catalysts are also very stable in the presence of water vapour, which gives them potential for application in after-treatment processes.