文献类型：期刊文献

英文题名：CO/(CO+CO2) ratio-controlled iron carbide in NaFeZn/CLD-modified HZSM-5 catalysts for selective aromatics synthesis via bifunctional catalysis

作者：Wu, Fangyi[1];Wang, Tinghu[1];Zhu, Minghui[1];Yang, Zixu[1,3];Xu, Jing[1,2,3]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, State Key Lab Green Chem Engn & Ind Catalysis, Shanghai 200237, Peoples R China;[2]Guangxi Univ, Univ Engn Res Ctr Green Chem New Mat, Sch Chem & Chem Engn, Nanning 530004, Guangxi, Peoples R China;[3]East China Univ Sci & Technol, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2027

卷号：427

外文期刊名：FUEL

收录：;WOS:【SCI-EXPANDED(收录号:WOS:001761778700001)】；

基金：The authors gratefully acknowledge financial support from the Coal-Major Project (No. 2025ZD1701300) , the Guangxi Science and Technology Program (LT2504240025) , the National Natural Science Foundation of China (NSFC, Nos. 22378118 and 22278405) .

语种：英文

外文关键词：Reactant-driven structural reconstruction; Carbon chemical potential; Chain growth ability; Olefin intermediates; Aromatic; CO/CO2 mixtures

摘要：Controlling iron carbide speciation in COx hydrogenation-via feed CO/(CO+CO2) ratio-modulates chain-growth probability and thereby tunes the selectivity of olefin intermediates that feed downstream aromatization over zeolite acid sites. Systematic variation of CO/(CO+CO2) ratio from 0 to 1.0 spans surface carbon chemical potential from -6.95 to -6.41 eV (DFT + JANAF thermochemistry), shifting the carburization-oxidation equilibrium from 73% Fe5C2 (pure CO2) to a maximum 95% (ratio 0.5, 57Fe Mo & uml;ssbauer spectroscopy). Maximum Fe5C2 content correlates with peak chain-growth probability (alpha = 0.75, Anderson-Schulz-Flory), yielding 46.6% C5+= olefin selectivity-23% higher than pure CO2 feed-which preferentially undergoes oligomerization-cyclization on CLD-modified HZSM-5 (external acid sites removed), achieving 51.8% aromatics selectivity. Under pure CO (mu C = -6.41 eV), although carburization is thermodynamically favorable, the enhanced thermodynamic driving force for carbon deposition and the accelerated kinetics of the Boudouard reaction cause a graphitic overlayer (8.3 nm thick by TEM) to form more rapidly than bulk carburization. This reduces the accessibility of Fe5C2 sites and lowers alpha to 0.68. Integrating optimal-ratio NaFeZn with modified zeolite yields STY = 21.1 molAro.& sdot;kgcat-1 & sdot;h-1, ranking in the top quartile of Fe-based systems. The results suggest that mu C-mediated phase evolution provides a useful framework for understanding catalyst behavior under varying CO/CO2 feed compositions and may offer guidance for catalyst regulation under industrially relevant fluctuating syngas conditions.