![]() However, the most serious issue of Ni-based catalyst is easy to sinter and carbon deposit, leading to deactivation of the catalysts. The Ni is relatively cheap and widely used in industrial hydrogen production. However, the high price and scarce resources of noble metal limit its industrial application prospect, while non-noble metals such as Ni, Co, and Fe also show high initial activity (Nagaoka et al., 2003 Guo et al., 2004 Wang et al., 2011 Djinović et al., 2012). ( 2001b) studied the high-pressure reaction performance of Ru/TiO 2 catalyst for DRM reaction and found that the 2%Ru/TiO 2 catalyst showed excellent carbon resistance at 750☌ and 2 MPa pressure. ( 2001a) loaded Pt on ZrO 2 and Al 2O 3, respectively, to study the effect of support on DRM reaction, and results showed that ZrO 2 had better performance and could run for 500 h without loss of activity. Noble metal catalysts such as Pt, Pd, Rh, and Ru have high activity, high stability, and excellent carbon resistance in DRM reaction (Graf et al., 2007 Özkara-Aydinoglu et al., 2009). The DRM reaction catalysts can be classified into noble metal catalysts and non-noble metal catalysts according to the active metal component. In recent years, DRM reaction has made significant progress in industrial applications, but large-scale commercial distribution has yet to address the following issues: catalyst thermal stability and carbon resistance (Bian et al., 2016). In general, syngas can be converted to liquid fuel by Fischer–Tropsch process or removed from CO via pressure swing adsorption (PSA) to obtain high purity hydrogen (99.999%) which can be used in proton exchange membrane fuel cell (PEMFC) (Miura et al., 2012, 2013 Qiu et al., 2017 Rosli et al., 2017). CH 4 and CO 2 can be catalytic converted to syngas (CO and H 2) by dry reforming of CH 4 (DRM) reaction. Indirect transformation of CH 4 includes steam reforming, CO 2 dry reforming, and partial oxidation, etc. In addition, the complex product composition greatly limits the use of CH 4. ![]() However, due to the difficulty of activation of CH 4 molecule, direct conversion is usually conducted under harsh conditions of high temperature, high pressure, and high energy consumption. The simple conversion process has potential theoretical advantages. Direct transformation of CH 4 includes oxidation coupling, chlorination coupling, and direct dehydrogenation (Otsuka et al., 1987 Sun and Klabunde, 1999 Zhang et al., 2015). As the main component of natural gas, there are direct and indirect methods for effective use of methane (CH 4) (Reddy et al., 2013). With the breakthrough of shale gas exploitation technology, the application of natural gas has become a worldwide research hotspot in recent years (Wu et al., 2016 Middleton et al., 2017). The global fossil-energy revolution has begun, with abundant and cheap natural gas accounting for a growing share of the world's energy consumption. On the other hand, coal and oil are non-renewable resources, and the reserves are limited and dwindling. When fossil fuels are used, a large amount of greenhouse gas-CO 2 will be produced, accompanied by the generation of polluted flue gas, leading to increasingly serious environmental pollution (Michael et al., 1993 Gurney et al., 2009). Therefore, the efficient and thermally stable 2 core–shell catalyst has a promising application prospect in DRM reaction and can make a considerable contribution to the sustainable use of energy.Ĭoal and oil are the most important energy consumed in the world fossil fuels accounted for 85% of global energy consumption in 2018. In addition, NiPt NPs had better activity than Ni NPs and Pt NPs because Ni and Pt formed as alloy in NiPt NPs. By characterization, we learned that hollow structure had an inner surface and thus had a larger active specific surface area than NP structure. In contrast to the continuous deactivation of the supported catalyst, all the core–shell catalysts were able to maintain stability for 200 h, and the activity sequence was Hollow-NiPt > NiPt NPs > Pt NPs > Ni NPs. In addition, the activity and stability of core–shell catalysts with different nuclei were tested. Compared with hollow-NiPt/SiO 2 supported catalyst, the 2 core–shell catalyst exhibited better activity and thermal stability in dry reforming of methane (CH 4) (DRM) with CO 2 reaction, with CH 4/CO 2 conversion to 97% and service life to 200 h at 800☌, respectively. A neoteric 2 core–shell structure catalyst with 7-nm-sized hollow NiPt alloy nanoparticle (NP) packaged by SiO 2 shell was prepared by a classic Stober method.
0 Comments
Leave a Reply. |