No abstract

Methane dry reforming (MDR) is a very important reaction, which can efficiently use two kinds of greenhouse gases (CO2 and CH4) to prepare synthesis gas or produce green hydrogen energy. What inhibits the industrialization of MDR is the sintering of active Ni nanoparticles and severe carbon deposition for Ni‐based catalysts. To resolve these problems, a novel structured catalyst with multiple ultra‐small Ni nanoparticles (4.3 nm) as the core and microporous silica as the shell was rationally fabricated by a facial one‐pot reverse micelle method and applied for MDR. The multiple‐cores@shell (M‐Ni@SiO2) catalyst displays superior carbon resistance and long‐term durability with the methane and carbon dioxide conversion close to thermodynamic equilibrium and a H2 to CO molar ratio near 1, whereas the commercial catalyst, Ni/Al2O3, and Ni directly supported on silica spheres (Ni/SiO2) show low stability and notable carbon deposition. The ultra‐small Ni particle size and confinement effect of the porous silica shell are believed to be the determining factors for the outstanding performance of the multiple‐cores@shell catalyst. The novel multiple‐cores@shell structure catalyst could be potentially used for industrial applications of MDR.

No abstract

1.1 nm Pd nanoparticles embedded in silica nanospheres were prepared by an improved one-step reverse micelle method, which show superior activity and thermal stability. Pd active surface area is the determining factors for the activity.

A novel MOF-derived MnCoOx nanoparticles embedded in porous N-doped carbon catalyst exhibits excellent catalytic activity for the low-temperature oxidation of formaldehyde.

Catalytic oxidation of formaldehyde (HCHO) is the most efficient way to purify indoor air of HCHO pollutant. This work investigated rare earth La-doped Pt/TiO2 for low concentration HCHO oxidation at room temperature. La-doped Pt/TiO2 had a dramatically promoted catalytic performance for HCHO oxidation. The reasons for the La promotion effect were investigated by N2 adsorption, X-ray diffraction, CO chemisorption, X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and high-angle annular dark field scanning TEM. The Pt nanoparticle size was reduced to 1.7 nm from 2.2 nm after modification by La, which led to higher Pt dispersion, more exposed active sites and enhanced metal-support interaction. Thus a superior activity for indoor low concentration HCHO oxidation was obtained. Moreover, the La-doped TiO2 can be wash-coated on a cordierite monolith so that very low amounts of Pt (0.01 wt%) can be used. The catalyst was evaluated in a simulated indoor HCHO elimination environment and displayed high purifying efficiency and stability. It can be potentially used as a commercial catalyst for indoor HCHO elimination.

A high-surface area (572 m2 g–1) dendritic mesoporous silica (KCC-1) was synthesized successfully and used as a support to confine Pt–Ni bimetallic nanoparticles (NPs). It is revealed that the Pt–Ni NPs are highly dispersed with an ultra-small size of 1.0 nm, and the large specific surface area as well as the abundant mesoporous structure of dendritic KCC-1 can effectively promote the dispersion and the thermal stability of Pt–Ni nanoparticles, thus significantly improving the CO oxidation activity. Compared with monometallic 1% Pt/KCC-1 and 1% Ni/KCC-1 catalysts, the combination of Pt and Ni together with a suitable ratio can further enhance the activity of the catalyst due to the synergetic effect between Pt and Ni. Over the 1% Pt7Ni3/KCC-1, the optimal catalyst in this study, 100% CO conversion was achieved at 100 °C. The incorporation of Ni into Pt leads to a reduction in the amount of noble metal required while simultaneously enhancing catalytic activity. This study offers a pathway for designing CO oxidation catalysts with low precious metal loading, yet exhibiting superior catalytic activity.