Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202508101
The emission of sulfur dioxide (SO2) and nitrogen oxides (NOx) from fossil fuel combustion and metal smelting industries poses severe risks to environmental and human health. This study utilized depleted lead-zinc molten slag as a desulfurizer for wet flue gas desulfurization, and the resulting desulfurization slurry was further employed for NOx removal, achieving resource utilization. The desulfurization efficiency of the slag was determined, and NaClO2 was identified as the most effective oxidant when combined with the slag slurry for NOx removal. The effects of NaClO2 concentration, reaction temperature, flue gas flow rate, oxygen concentration, NOx concentration, and pH on removal efficiency were investigated. Optimal conditions were found at NaClO2 concentration of 2.5 mmol·L−1, temperature 45 °C, flue gas flow 200 mL·min−1, O2 volume fraction 10%, NOx volume fraction 0.03%, and pH 6, achieving a NOx removal efficiency of 97.24%. Metal ion experiments revealed that Fe3+, Zn2+, Mn2+, and K+ exhibited synergistic effects with NaClO2, with Fe3+ showing the most significant enhancement. Fe3+ promoted the decomposition of NaClO2 to generate stronger oxidants such as ClO2, thereby enhancing NOx oxidation and absorption. This approach offers a cost-effective and environmentally friendly alternative to traditional selective catalytic reduction, avoiding ammonia slip and secondary pollution.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202607001
Co-combustion of municipal solid waste (MSW) and sewage sludge (SS) offers a promising route for synergistic waste management, yet pollutant release dynamics and environmental trade-offs remain inadequately characterized. This study systematically investigated the combustion behavior, pollutant emissions, and environmental impacts of MSW-SS blends at 850, 950, and 1050 °C with varying SS mass fractions (0–100%). Machine learning models, particularly artificial neural networks (ANN), were optimized to predict pollutant generation, and SHAP analysis identified key influencing factors. Results demonstrated that combustion temperature and blending ratio significantly affected burnout efficiency, with temperature exerting a more pronounced effect. An SS proportion of 20% yielded favorable combustion performance. Among pollutants, N2O and C2H4 emissions were significantly influenced by temperature, blending ratio, and their interaction, indicating high sensitivity to operating conditions. CO and C6H6 were primarily affected by blending ratio, while C7H8 responded to both temperature and blending ratio. N2O and CH4 were predominantly released during the initial combustion stage; elevated temperatures markedly suppressed N2O formation, and co-combustion generally reduced CH4 emissions. A 20% SS blend effectively reduced SO2 emissions, and NO synergistic reduction was optimal at 950 °C. Emissions of CO, C2H4, C6H6, and C7H8 exhibited antagonistic behavior under co-combustion. The ANN model accurately predicted pollutant concentrations, with combustion temperature, volatile matter, and fixed carbon content identified as critical factors. Environmental impact assessment revealed that higher temperatures reduced global warming potential (GWP) and photochemical ozone creation potential (POCP), while lower MSW proportions decreased POCP but increased GWP and acidification potential (AP). Integrating combustion performance, pollutant release, and environmental impacts, an SS proportion of 20% is recommended for optimized co-combustion.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.1016/S1872-5813(26)60721-9
Methane (CH4), the primary component of natural gas, is an ideal feedstock for producing high-value chemicals and clean fuels due to its high hydrogen-to-carbon ratio. However, its chemical inertness poses significant challenges, and traditional thermal catalytic reforming processes suffer from long reaction pathways and high energy consumption. Photocatalytic technology enables highly selective CH4 conversion under mild conditions, even at room temperature, offering environmental and economic benefits. This review systematically summarizes recent advances in room-temperature photocatalytic systems for direct CH4 conversion. It begins by elucidating the mechanisms, product distributions, and inherent challenges of four key reaction pathways: partial oxidation, non-oxidative coupling, oxidative coupling, and oxidative carbonylation. The discussion then addresses the critical role of catalyst architecture, focusing on semiconductor supports, metal site modulation, and advanced porous frameworks. Furthermore, reactor design and process intensification strategies are examined, including batch and continuous-flow reactors, novel structured reactors, and photo-electro and photo-thermo synergistic approaches. Finally, reaction mechanisms are summarized. Despite progress, challenges remain in fundamental understanding, performance evaluation, and technological integration. Future efforts should focus on mechanistic studies, standardization of evaluation protocols, development of non-noble metal catalysts, system optimization, and comprehensive sustainability assessments.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4099-2
Lithium (Li)-metal batteries (LMBs) are promising next-generation energy storage systems due to their high theoretical capacity (3860 mAh g−1) and low electrochemical potential (−3.04 V vs. standard hydrogen electrode). However, uncontrollable Li dendrite growth and volume fluctuations during cycling cause low Coulombic efficiency, safety hazards, and rapid capacity decay. Conventional 3D current collectors mitigate these issues by increasing surface area and providing void space, but they suffer from top-heavy deposition and underutilization of internal space. Emerging Janus/gradient anode structures, featuring asymmetric or gradient properties in lithiophilicity, conductivity, or porosity, enable bottom-up Li plating and efficient space utilization. This review systematically summarizes design principles, operational mechanisms, and recent progress in lithiophilic-lithiophobic Janus designs, conductivity-gradient frameworks, and dual-gradient configurations. These structures collectively improve Coulombic efficiency, cyclic longevity, and safety. The review concludes with future research directions, underscoring the potential of Janus/gradient anodes for high-energy-density and durable LMBs.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3387-6
Defect engineering is pivotal in comprehending physical mechanisms that govern carrier transport and device performance. The defect evolution and carrier manipulation in Sn-doped Ga2O3 bulk crystals subjected to different thermal treatments were investigated, utilizing depth-profiled deep-level transient spectroscopy (DLTS) and frequency-dependent capacitance-voltage (C-V-f) techniques. In untreated Sn-doped Ga2O3 with an electron concentration of 6.37×10^17 cm^-3, two dominant electron traps, ET1 (EC−0.68 eV) and ET2 (EC−0.76 eV), were identified, corresponding to gallium vacancy (VGa) and the neutral complex of VGa-VO, respectively, and characterized as bulk traps. FeGa-related defects, ET3 (EC−0.84 eV), were concentrated near surface. Nitrogen annealing significantly reduced ET1, increased ET2 density from 6.13×10^15 to 1.1×10^16 cm^-3, and raised the interfacial state density (Dit) to 3.36×10^15 eV^-1 cm^-2, accompanied by an elevated electron concentration of 7.48×10^18 cm^-3. In contrast, air annealing enhanced ET1, with a density of 1.42×10^16 cm^-3, suppressed of ET2/ET3 traps, resulting in a lower Dit of 1.74×10^14 eV^-1 cm^-2, and a reduced electron concentration to 3.01×10^16 cm^-3. The findings reveal that a reducing environment induces VO formation and converts discrete VGa acceptors into neutral VGa-VO complexes, leading to downward surface band bending and electron accumulation. Conversely, VGa-VO complexes are dissociated into VGa acceptors in oxidizing conditions, leading to an upward surface band bending and electron compensation. This work underscores the carrier concentration manipulation by defect engineering in Ga2O3, offering insights essential for developing high-performance gallium oxide electronics.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3497-6
Graphdiyne (GDY) possesses a tunable intrinsic bandgap, high charge carrier mobility, and broad-spectrum absorption, making it a candidate for photocatalytic hydrogen evolution. However, GDY/wide-band semiconductor photocatalysts are constrained by low doping concentrations and insufficient absorption in the visible-to-near-infrared (Vis-NIR) region, which limits full-spectrum energy utilization. To address these limitations, functional graphdiyne quantum dots (PG-QDs) incorporating perylene diimide (PDI) units were designed and synthesized. The PG-QDs exhibit tailored spectral absorption, reducing competition with wide-band semiconductors for UV light while enhancing Vis-NIR absorption and photothermal conversion. The PG-QDs overcome the doping concentration limitations of conventional GDY-based photocatalysts, achieving an optimal doping ratio of 15% without suppressing hydrogen evolution activity. The pronounced photothermal effect effectively suppresses the recombination of photogenerated carriers and enhances charge carrier separation efficiency. The hydrogen evolution rate reached 12.69 mmol g−1 h−1, over thirty times higher than that of P25. This study presents a strategy for improving the full-spectrum energy utilization of GDY-based photocatalysts.