文献类型：期刊文献

英文题名：Role of hydroxyl groups in biomass char CO2 gasification: insights into CO2/H2O co-gasification

作者：Liu, Xuesong[1,2];Yuan, Wenhao[1,2];Tang, Longfei[1];Sun, Zhuang[3];Gao, Yuan[4,5];Wang, Fuchen[1];Mosquedac, Alexander O.[6];Lam, Su Shiung[7,9];Ding, Lu[1,2,8];Yu, Guangsuo[1]

机构：[1]East China Univ Sci & Technol, Inst Clean Coal Technol, Shanghai 200237, Peoples R China;[2]Engn Res Ctr Resource Utilizat Carbon Containing W, Shanghai 200237, Peoples R China;[3]Inst Sci Tokyo, Sch Environm & Soc, Dept Transdisciplinary Sci & Engn, 2-12-1 Ookayama, Meguro Ku, Tokyo 1528550, Japan;[4]Kyushu Univ, Int Inst Carbon Neutral Energy Res WPI I2CNER, Ctr Energy Syst Design, Fukuoka 8190395, Japan;[5]Kyushu Univ, Inst Adv Study, Fukuoka 8190395, Japan;[6]Mindanao State Univ, Iligan Inst Technol, Ctr Energy Res & Technol, Waste Valorizat & Energy Lab, Iligan 9200, Philippines;[7]Univ Malaysia Terengganu, Higher Inst Ctr Excellence HICoE, Inst Trop Aquaculture & Fisheries AKUATROP, Kuala Nerus 21030, Terengganu, Malaysia;[8]State Key Lab Chem Engn & Low Carbon Technol, Shanghai 200237, Peoples R China;[9]Chandigarh Univ, Univ Ctr Res & Dev, Dept Chem, Mohali, Punjab, India

年份：2027

卷号：337

外文期刊名：CHEMICAL ENGINEERING SCIENCE

收录：;WOS:【SCI-EXPANDED(收录号:WOS:001831135000001)】；

基金：This study is supported by the project of National Key Research and Development Program of China (2023YFB4203803) .

语种：英文

外文关键词：Biomass char; Hydroxyl group; Density functional theory; Reaction mechanism; Synergistic gasification; CO2 gasification

摘要：Hydroxyl species (OH) generated from H2O are widely recognized as important reactive intermediates influencing biomass char conversion under CO2/H2O atmospheres. However, the microscopic role of OH in regulating CO2 gasification and the origin of the synergistic effect observed during CO2/H2O co-gasification remain unclear. In this study, density functional theory (DFT) calculations combined with wavefunction analysis were employed to investigate the interactions among OH, CO2, and char model. Three representative reaction pathways, including direct CO2 gasification, OH co-adsorption-assisted gasification, and OH-induced surface-modification gasification, were systematically compared. The results show that OH exhibits stronger adsorption affinity than CO2 and preferentially occupies active sites on the char surface. In the co-adsorption pathway, OH promotes the initial activation of CO2 but inhibits the rate-determining CO exposure step. More importantly, OH-induced surface reconstruction generates new active sites and fundamentally alters the gasification pathway, significantly reducing the rate-determining energy barrier and enhancing reaction kinetics. The kinetic behavior of the proposed pathways was evaluated within the typical gasification temperature range (800-1600 degrees C). Kinetic analysis indicates that the gasification reactivity follows the order of OH-modified char >OH-free char >OH co-adsorption char. A key finding of this work is the identification of a dual-role mechanism of OH during biomass char gasification. OH, simultaneously acts as a reaction intermediate and a surface-reconstruction agent, resulting in two fundamentally different gasification pathways and kinetic behaviors. The proposed mechanism provides new atomic-scale insights into the synergistic behavior observed during CO2/H2O co-gasification.