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CO/CO 2 hydrogenation has attracted much attention as a pathway to achieve carbon neutrality and production of synthetic natural gas (SNG). In this work, two-dimensional NiAl layered double oxide (2D NiAl-LDO) has been successfully decorated by SiO 2 nanoparticles derived from SiCl 4 and used as CO/CO 2 methanation catalysts. The as-obtained H-SiO 2 -NiAl-LDO exhibited a large specific surface area of 201 m 2 /g as well as high ratio of metallic Ni 0 species and surface adsorption oxygen that were beneficial for low-temperature methanation of CO/CO 2 . The conversion of CO methanation was 99% at 400 °C, and that of CO 2 was 90% at 350 °C. At 250 °C, the CO methanation reached 85% whereas that of CO 2 reached 23% at 200 °C. We believe that this provides a simple method to improve the methanation performance of CO and CO 2 and a strategy for the modification of other similar catalysts.

At present, the research focus has been aimed at the pursuit of the design and synthesis of catalysts for effective photocatalytic degradation of organic pollutants in wastewater, and further exploration of novel materials of the photodegradation catalyst. In this paper, the Sol-gel route after thermal treatment was used to produce NiFe 2 O 4 carbon aerogel (NiFe 2 O 4 -CA) nanocomposites with cotton linter cellulose as the precursor of aerogel, by co-precipitating iron and nickel salts onto its substrate. The structure and composition of these materials were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Raman spectra, high-resolution scanning electron microscopy (HR-SEM), high-resolution scanning electron microscope mapping (SEM-mapping), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET)'s surface area. The magnetic properties of the material were analyzed by a vibrating-sample magnetometer (VSM). Moreover, diffuse reflectance spectra (DRS), electrochemical impedance spectroscopy (EIS) and photo-luminescence spectroscopy (PL) characterized the photoelectric properties of this cellulose-aerogels-based NiFe 2 O 4 -CA. Methylene blue (MB) acted as the simulated pollutant, and the photocatalytic activity of NiFe 2 O 4 -CA nanocomposites under visible light was evaluated by adjusting H 2 O 2 content and the pH value. The results showed that the optical absorption range of nickel ferrite was broadened by doping cellulose-aerogels-based carbon, which exerted more positive effects on photocatalytic reactions. This is because the doping of this aerogel carbon promoted a more uniform distribution of NiFe 2 O 4 particles. Given the Methylene blue (MB) degradation reaction conformed to the first-order kinetic equation, the NiFe 2 O 4 -CA nanocomposites conducted excellent catalytic activity by maintaining almost 99% of the removal of MB (60 mg/L) within 180 min and upheld excellent stability over four consecutive cycles. This study indicated that NiFe 2 O 4 -CA nanocomposites reserved the potential as a future effective treatment of dye wastewater.