DBD plasma-assisted dry reforming of methane over Ni/SiO2
ZHENG Zhaoyu;XU Bo;ZENG Aonan;WANG Anjie;LIU Yingya;SUN Zhichao;WANG Yao
分别采用沉积沉淀法(DP)和浸渍法(IMP)制备Ni/SiO2催化剂前体,前体经H2还原得到Ni/SiO2-DP和Ni/SiO2-IMP。对所制备的催化剂进行X射线衍射、X射线光电子能谱、N2吸附-脱附、化学吸附、傅里叶变换红外、透射电镜和拉曼光谱表征,并考察其与介质阻挡放电等离子体(DBD)协同催化甲烷干重整(DRM)制合成气反应性能。研究结果表明,相较于Ni/SiO2-IMP,Ni/SiO2-DP因其较小的Ni颗粒尺寸、Ni与载体的强相互作用以及对反应物分子较强的吸附活化能力,具有更高的催化活性和稳定性。对Ni/SiO2-DP制备条件考察结果表明,H2等离子体还原(PR)的Ni/SiO2-DP-PR比程序升温还原(TPR)的Ni/SiO2-DP-TPR具有更高的催化活性。沉积沉淀时间为10 h,H2等离子体还原时间为30 min时,CH4和CO2转化率分别为72.5%和78.2%,H2和CO选择性分别为86.7%和94.2%,能量利用率为4.36 mmol/kJ。
Dry reforming of methane reaction (DRM) can convert CH4 and CO2 into syngas, which can be further utilized to produce valuable chemicals, such as hydrocarbons and liquid oxygenates. Traditionally, nickel-based catalysts have been employed for thermal catalytic DRM, which requires relatively high temperatures (>700 ℃). However, the high temperatures lead to issues such as nickel sintering, carbon deposition, and low energy efficiency, limiting the practical applications. Dielectric barrier discharge plasma (DBD) can cooperate with Ni-based catalysts, allowing the reaction to work under lower temperatures. Developing catalysts with strong synergy and high resistance to carbon coking is crucial for this technique. In this work, nickel phyllosilicate was used as a precursor to prepare highly dispersed Ni-based catalysts using H2 plasma reduction. The obtained catalysts were then used with DBD plasma to catalyze the DRM reaction. Nickel phyllosilicate was prepared using deposition-precipitation method, followed by calcination and reduction to obtain Ni/SiO2-DP. As a comparison, Ni/SiO2-IMP was prepared using the traditional impregnation method. All catalysts were characterized using XRD, XPS, N2-adsorption-desorption, H2-TPR, chemisorption, FT-IR, TEM, TG and Raman spectroscopy. The catalytic performance of DRM reaction was evaluated in a DBD reactor. Ni/SiO2-DP exhibited higher activity and stability in DRM reaction compared to Ni/SiO2-IMP. Combining with the characterization results, the better performance was attributed to the enhanced interaction between Ni and SiO2 in Ni/SiO2-DP, resulting from the NiPS precursor. Such interaction led to higher dispersion and smaller particle sizes, which effectively suppressed carbon coking and improved the stability. In contrast, the weaker interaction between Ni and SiO2 in Ni/SiO2-IMP, along with larger Ni particles, resulted in rapid carbon deposition and sintering, leading to a rapid decrease in catalytic activity. Additionally, according to the CO2-TPD results, Ni/SiO2-DP has stronger CO2 adsorption capacity than Ni/SiO2-IMP, which allows an enrichment of a large amount of CO2*, CO*, and O* active oxygen species on the catalyst surface. These species can further react with CH
CH4/CO2 reforming;Ni/SiO2;dielectric barrier discharge plasma
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会