Ji Yaxiong,Lin Shuang,Xu Guihong,Chen Tianen,Gong Jianchao,Meng Fanbin,Wang Yuanhao
Abstract Catalytic conversion of CO 2 to methanol with H 2 from renewable energy has attracted increasing interest as a promising strategy for reducing excessive CO 2 emissions. However, the performance of reported various catalysts still suffers from low methanol yield with a passable CO 2 conversion. In this work, Cu–ZnO–La 2 O 3 interfaces are constructed with various La 2 O 3 mole ratio. Compared to Cu/ZnO, the optimized catalyst (i.e., Cu 0.6 Zn 0.2 La 0.4 ) exhibits a much higher mass-specific methanol formation rate (159.3 g MeOH /kg cat /h) at 240 °C and 3 MPa. A series of ex-situ and in-situ characterizations, such as X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), N 2 O titration measurements, and in-situ diffuse reflectance Fourier transform infrared spectroscopy ( in-situ DRIFTS) study, are used to investigate its structure and mechanism study. The dispersion of Cu over Cu/ZnO/La 2 O 3 catalyst is significantly enhanced, forming more Cu–ZnO–La 2 O 3 interfaces. LaO x species favor CO 2 activation and generate more carbon intermediates species for CO 2 hydrogenation. Furthermore, more Cu + is bonded, which stabilizes the key intermediate, inhibits its desorption, and facilitates its further hydrogenation to methanol. This work is expected to offer an effective strategy to develop new catalysts with high performance for CO 2 hydrogenation to methanol. Graphical Abstract
Jun Ma,Shiyan Li,Bing Xu,Wei Chu,Qian Jiang,Yuefeng Liu
Converting CO 2 from the coal chemical industry into natural gas via methanation reaction, coupled with green hydrogen, is a promising strategy for reducing carbon emissions. While Ni-based catalysts are cost-effective and widely used for CO 2 methanation, their performance is often hindered by low temperatures activity. We confined LaO x species within the mesoporous silica (mSiO 2 ) channels to serve as a support for Ni-based CO 2 methanation catalysts. The results demonstrate that LaO x introduction (3.9 wt%) significantly improves CO 2 conversion from 38.2 % to 74.4 %, while enhancing CH 4 selectivity from 94.8 % to 99.7 % at 300 °C. Interestingly, excessive La loading does not noticeably reduce the promotion efficiency. Detailed characterization revealed that ultrafine LaO x species anchored within silica framework improved the dispersion and reduction of Ni nanoparticles and served as strong basic sites to promote CO 2 dissociation. In-situ DRIFT and isotope studies demonstrated that LaO x facilitated the hydrogenation of formate intermediates, enhancing both CO 2 conversion and CH 4 selectivity. In addition, LaO x endowed the support with hydrogen spillover capability, enabling active H from Ni nanoparticles to migrate to LaO x sites and accelerate the conversion of formate intermediates into CH 4 . These results underscore the potential of LaO x -modified mesoporous silica to optimize Ni-based catalysts, offering valuable guidance for the design of high-performance CO 2 hydrogenation catalyst supports.
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