A plasma–catalyst hybrid system has been developed for the direct conversion of methane to C₂₊ hydrocarbons in dielectric barrier discharge (DBD) plasma. TiO₂ presented the highest C₂₊ yield of 11.63% among different dielectric materials when integrated with DBD plasma, which made us concentrate on the TiO₂-based catalyst. It was demonstrated that MnTi catalyst showed the best methane coupling performance of 27.29% C₂₊ yield with 150 V applied voltage, without additional thermal input. The catalytic performance of MnTi catalyst under various operation parameters was further carried out, and different techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and H₂-temperature-programmed reduction were used to explore the effect of Mn loading on methane oxidative coupling (OCM) performance. The results showed that applied voltage and flow rate had a significant effect on methane activation. The dielectric particles of TiO₂ loaded with Mn not only synergistically affected the coupling reaction, but also facilitated charge deposition to generate a strong local electric field to activate methane. The synergy effects boosted the OCM performance and the C₂₊ yield became 1.25 times higher than that of the undoped TiO₂ under identical operating conditions in plasma, which was almost impossible to occur even at 850 °C on the MnTi catalyst in the absence of plasma. Moreover, the reaction activity of the catalyst was fully recovered by plasma regeneration at 300 °C and maintained its stability in for at least 30 consecutive cyclic redox tests. This work presents a new opportunity for efficient methane conversion to produce C₂₊ at low temperatures by plasma assistance.

The catalytic fast pyrolysis (CFP) of bio-derived furans offers a promising approach for sustainable aromatic production. ZSM-5 modified by different metal species (Zn, Mo, Fe, and Ga) was employed in the CFP of bio-derived furans for enhancing aromatic production. The effects of metal species, metal loadings, and the weight hourly space velocity (WHSV) on the product distributions from the CFP of 2-methylfuran (MF) were systemically investigated. It is found that the introduction of Zn, Mo, Fe, and Ga on ZSM-5 significantly increases the MF conversion and aromatic yields. The maximum MF conversions of 75.49 and 69.03% are obtained, respectively, by Fe-ZSM-5 and Ga-ZSM-5, which boost the aromatic yield by 34.5 and 42.7% compared to ZSM-5. The optimal loading of Fe on ZSM-5 is 2%. Additionally, the highest aromatic yield of 40.03% is achieved by 2%Fe-ZSM-5 at a WHSV of 2 h⁻¹. The catalyst characterization demonstrates that the synergistic effect of Brønsted and Lewis acid sites in Fe-ZSM-5 is responsible for achieving the efficient aromatization of MF. The key to designing improved zeolite catalysts for MF aromatization is the introduction of large numbers of new Lewis acid sites without a significant loss of Brønsted acid sites in ZSM-5. These findings can provide guidelines for the rational design of better zeolite catalysts used in the CFP of biomass and its derived furans.

The formation of slagging and fouling during municipal solid waste (MSW) incineration not only significantly affects heat transfer, but also results in shortened operating cycles. In order to solve the issues, the effect of different additives on the migration and transformation patterns of alkali/alkaline earth metals (AAEM) and chlorine during MSW incineration is screened based on the Gibbs energy minimization method. The effect of potential additives on the ash fusion temperature and combustion reactivity of MSW char is subsequently verified and evaluated by experimental methods. The thermodynamic equilibrium analysis shows that Al(NO₃)₃, Ca(NO₃)₂, and Mg(NO₃)₂ have great potential to increase the ash fusion temperature. The experimental investigation confirms that the addition of Al(NO₃)₃, Ca(NO₃)₂, and Mg(NO₃)₂ significantly increases the ash fusion temperature. The order of increasing the ash fusion temperature by different additives is Mg(NO₃)₂ > Ca(NO₃)₂ > Al(NO₃)₃. The addition of Mg(NO₃)₂ significantly increased the initial deformation temperature, softening temperature, hemispheric temperature, and flow temperature of ash from 1180, 1190, 1200, and 1240 °C to 1220, 1230, 1240, and 1260 °C, respectively. The addition of Cu(NO3)2, Fe(NO3)3, and KMnO4 significantly decreases the temperature at the maximum weight loss rate of MSW char, while increasing the maximum weight loss rate. Additionally, Cu(NO₃)₂ shows the best performance in improving the combustion reactivity of MSW char. The addition of Cu(NO₃)₂ evidently increases the maximum weight loss rate from 0.49 to 0.54% °C⁻¹. Therefore, it is concluded that Mg(NO₃)₂ and Cu(NO₃)₂ are supposed to be the most potential candidates for efficient additives. This study presents an efficient and economical method to screen potential additives for alleviating slagging and fouling during MSW incineration.