Chen Sai, Pei Chunlei, Chang Xin, Zhao Zhi-Jian, Mu Rentao, Xu Yiyi, Gong Jinlong
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University; Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China.
Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China.
Angew Chem Int Ed Engl. 2020 Dec 1;59(49):22072-22079. doi: 10.1002/anie.202005968. Epub 2020 Sep 29.
Chemical looping provides an energy- and cost-effective route for alkane utilization. However, there is considerable CO co-production caused by kinetically mismatched O bulk diffusion and surface reaction in current chemical looping oxidative dehydrogenation systems, rendering a decreased olefin productivity. Sub-monolayer or monolayer vanadia nanostructures are successfully constructed to suppress CO production in oxidative dehydrogenation of propane by evading the interference of O bulk diffusion (monolayer versus multi-layers). The highly dispersed vanadia nanostructures on titanium dioxide support showed over 90 % propylene selectivity at 500 °C, exhibiting turnover frequency of 1.9×10 s , which is over 20 times greater than that of conventional crystalline V O . Combining in situ spectroscopic characterizations and DFT calculations, we reveal the loading-reaction barrier relationship through the vanadia/titanium interfacial interaction.
化学链化为烷烃利用提供了一条能源和成本效益高的途径。然而，在当前的化学链氧化脱氢系统中，由于氧体相扩散和表面反应在动力学上不匹配，会产生大量的一氧化碳副产物，导致烯烃生产率降低。通过避免体相氧扩散的干扰（单层与多层），成功构建了亚单层或单层钒氧化物纳米结构，以抑制丙烷氧化脱氢过程中的一氧化碳生成。负载在二氧化钛载体上的高度分散的钒氧化物纳米结构在500°C时显示出超过90%的丙烯选择性，周转频率为1.9×10 s，比传统的结晶V₂O₅高20倍以上。结合原位光谱表征和密度泛函理论计算，我们通过钒氧化物/钛界面相互作用揭示了负载-反应势垒关系。
