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Verified CAS / Academic Author2 Decoded Studies

Prof. LI Ruikang

School of Energy and Environmental Engineering, Hebei University of Engineering, Handan, 056038, China

Research Publications & English Decoded Briefs

Showing 2 publications
Environmental Chemistry2026DOI: 10.7524/j.issn.0254-6108.2024112102

Emission Inventory and Scenario Prediction of Non-Road Mobile Sources in Hebei Province

Based on the 2022 activity data of non-road mobile sources in Hebei Province, this study employed the emission factor method recommended by the Guidelines to estimate emissions of CO, HC, NOx, PM2.5, PM10, and SO2. A comprehensive emission inventory was established, followed by spatial and uncertainty analyses. Scenario analysis, aligned with the 14th Five-Year Plan policies, was used to project emissions for 2030. The results indicate that non-road mobile sources in Hebei emitted 76.1×10^3 t of CO, 20.6×10^3 t of HC, 164.0×10^3 t of NOx, 8.5×10^3 t of PM2.5, 9.0×10^3 t of PM10, and 2.4×10^3 t of SO2. Agricultural machinery was the dominant contributor to CO, HC, PM2.5, and PM10, accounting for over 60.0% of CO emissions. Railway locomotives were the primary source of NOx, contributing 50.9%. For SO2, agricultural machinery and railway locomotives contributed 39.0% and 44.4%, respectively. The highest emitting cities were Tangshan (21.3%), Shijiazhuang (15.7%), Cangzhou (11.6%), and Handan (11.6%). Ship emissions were concentrated in Tangshan Port; civil aviation emissions were mainly in Shijiazhuang, Tangshan, Qinhuangdao, and Handan; railway emissions were distributed in Shijiazhuang, Baoding, and Handan. Under the updated emission standard scenario, NOx and PM10 emissions in 2030 could be reduced by approximately 35.0%. The phase-out of old machinery yielded the largest reduction in CO (36.0%), while both electrification and phase-out scenarios significantly impacted HC emissions.

Journal of Fuel Chemistry and Technology2026DOI: 10.3724/2097-213X.2025.JFCT.0035

Structural Evolution of χ-Fe5C2 and θ-Fe3C in the Reverse Water-Gas Shift Reaction

Iron-based catalysts in CO2/H2 atmospheres undergo dynamic carburization and oxidation phase transitions, complicating active-phase identification and stability control. This study prepared high-purity single-phase χ-Fe5C2 (Hägg carbide) and θ-Fe3C (cementite) via gas-solid carburization, with purity confirmed by XRD and Mössbauer spectroscopy. Fixed-bed reactor tests (H2/CO2 = 1, 0.1 MPa, 270–420 °C), pulse experiments (270 °C), and in situ XRD (10% CO2/He, 340 °C) were employed to investigate catalytic performance and structural evolution in the reverse water-gas shift (RWGS) reaction. Results show that χ-Fe5C2 exhibits higher RWGS activity but is more susceptible to oxidation, whereas θ-Fe3C demonstrates superior oxidation resistance but lower activity. Under RWGS conditions with H2, θ-Fe3C partially transforms into χ-Fe5C2; however, in 10% CO2 atmosphere, both carbides directly oxidize to Fe3O4 without inter-carbide transformation. In situ XRD at 340 °C and 0.1 MPa revealed that χ-Fe5C2 fully oxidizes within 11 h, while θ-Fe3C retains residual phase after 18.3 h, confirming its higher oxidation stability. These findings elucidate the atmosphere-dependent evolution mechanisms of χ-Fe5C2 and θ-Fe3C, providing experimental basis for phase-structure regulation and operational stability optimization in iron-based Fischer-Tropsch and RWGS catalysts.