塑料废弃物的电催化升级回收技术

废弃塑料已导致严重的生态环境问题,开发高效、环保和可持续的塑料升级回收技术是近年来备受关注的热点。与传统化学回收方法相比,电催化重整具有低能耗、无污染和高选择性等特点,能够在温和条件下将塑料氧化为小分子单体或高附加值化学品,在废弃物资源化利用等领域有着巨大的应用潜力。文中聚焦塑料电催化氧化技术的最新研究进展,系统总结了电催化重整技术在塑料升级回收方面的应用,着重探讨了各类电催化材料的性能与用途,并展望了塑料废弃物电催化回收技术的未来发展方向。

Ni-CeO_2/SBA-15电催化甲苯水蒸气重整的实验研究

以甲苯为生物质气化焦油的模型化合物,以Ni-Ce O2/SBA-15为催化剂,在自行搭建的固定床电化学催化(电催化)水蒸气重整实验台上进行了甲苯的电催化水蒸气重整实验,考察了电流强度、反应温度和水/碳摩尔比(S/C)对甲苯转化率、产气组成的影响,并对该催化剂进行了长时间活性测试。结果表明,电流的引入可以显著提高催化剂对甲苯的转化效率;在电流为4 A、反应温度为800℃、S/C为3时,甲苯转化率可以达到94.7%。

Effects of Current upon Electrochemical Catalytic Reforming of Anisole

The reforming of anisole （as model compound of bio-oil） was performed over the NiCuZn-Al2O3 catalyst, using a recently-developed electrochemical catalytic reforming （ECR）. The influence of-the current on the anisole reforming in the ECR process has been investigated. It was observed that anisole reforming was significantly enhanced by the current approached over the catalyst in the electrochemical catalytic process, which was due to the non-uniform temperature distribution in the catalytic bed and the role of the thermal electrons originating from the electrified wire. The maximum hydrogen yield of 88.7% with a carbon conversion of 98.3% was obtained through the ECR reforming of anisole at 700℃ and 4 A. X-ray diffraction was employed to characterize catalyst features and their alterations in the anisole reforming. The apparent activation energy for the anisole reforming is calculated as 99.54 kJ/mol, which is higher than ethanol, acetic acid, and light fraction of bio-oil. It should owe to different physical and chemical properties and reforming mechanism for different hydrocarbons.

Hydrogen Production From Crude Bio-oil and Biomass Char by Electrochemical Catalytic Reforming

We reports an efficient approach for production of hydrogen from crude bio-oil and biomass char in the dual fixed-bed system by using the electrochemical catalytic reforming method. The maximal absolute hydrogen yield reached 110.9 g H2/kg dry biomass. The product gas was a mixed gas containing 72%H2, 26%CO2, 1.9%CO, and a trace amount of CH4. It was observed that adding biomass char （a by-product of pyrolysis of biomass） could remarkably increase the absolute H2 yield （about 20%-50%）. The higher reforming temperature could enhance the steam reforming reaction of organic compounds in crude bio-oil and the reaction of CO and H20. In addition, the CuZn-Al2O3 catalyst in the water-gas shift bed could also increase the absolute H2 yield via shifting CO to CO2.

Hydrogen generation from methanol reforming for fuel cell applications: A review

Methanol is regarded as an important liquid fuel for hydrogen storage, transportation, and in-situ generation due to its convenient conveyance, high energy density, and low conversion temperature. In this work, an overview of state-of-the-art investigations on methanol reforming is critically summarized, including the detailed introduction of methanol conversion pathways from the perspective of fuel cell applications, various advanced materials design for catalytic methanol conversion, as well as the development of steam methanol reformers. For the section of utilization pathways, reactions such as steam reforming of methanol, partial oxidation of methanol, oxidative steam reforming of methanol, and sorption-enhanced steam methanol reforming were elaborated;For the catalyst section, the strategies to enhance the catalytic activity and other comprehensive performances were summarized;For the reactor section, the newly designed steam methanol reformers were thoroughly described. This review will benefit researchers from both fundamental research and fuel cell applications in the field of catalyzing methanol to hydrogen.

Effects of Current on Microcosmic Properties of Catalyst and Reforming of Bio-oil

Highly effective production of hydrogen from bio-oil was achieved by using a low-temperature electrochemical catalytic reforming approach over the conventional Ni-based reforming catalyst （NiO-Al2O3）, where an AC electronic current passed through the catalyst bed. The promoting effects of current on the bio-oil reforming were studied. It was found that the performance of the bio-oil reforming was remarkably enhanced by the current which passed through the catalyst. The effects of currents on the microcosmic properties of the catalyst, including the Brunauer-Emmett-Teller （BET） surface area, pore diameter, pore volume, the size of the crystallites and the reduction level of NiO into Ni, were carefully characterized by BET, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscope. The desorption of the thermal electrons from the electrified catalyst was directly observed by the TOF （time of flight） measurements. The mechanism of the electrochemical catalytic reforming of bio-oil is discussed based on the above investigation.