Carbon coated In2O3 hollow tubes embedded with ultra-low content ZnO quantum dots as catalysts for CO2 hydrogenation to methanol

Yuchen Shi; Weiguang Su; Xinyu Wei; Yonghui Bai; Xudong Song; Peng Lv; Jiaofei Wang; Guangsuo Yu

doi:10.1016/j.jcis.2023.01.008

Carbon coated In₂O₃ hollow tubes embedded with ultra-low content ZnO quantum dots as catalysts for CO₂ hydrogenation to methanol

J Colloid Interface Sci. 2023 Apr 15:636:141-152. doi: 10.1016/j.jcis.2023.01.008. Epub 2023 Jan 5.

Authors

Yuchen Shi¹, Weiguang Su², Xinyu Wei¹, Yonghui Bai¹, Xudong Song¹, Peng Lv¹, Jiaofei Wang¹, Guangsuo Yu³

Affiliations

¹ State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, China; College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China.
² State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, China; College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China. Electronic address: weiguangsu@nxu.edu.cn.
³ State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, China; Institute of Clean Coal Technology, East China University of Science and Technology, Shanghai 200237, China. Electronic address: gsyu@ecust.edu.cn.

PMID: 36623367
DOI: 10.1016/j.jcis.2023.01.008

Abstract

CO₂ hydrogenation coupled with renewable energy to produce methanol is of great interest. Carbon coated In₂O₃ hollow tube catalysts embedded with ultra-low content ZnO quantum dots (QDs) were synthesized for CO₂ hydrogenation to methanol. ZnO-In₂O₃-II catalyst had the highest CO₂ and H₂ adsorption capacity, which demonstrated the highest methanol formation rate. When CO₂ conversion was 8.9%, methanol selectivity still exceeded 86% at 3.0 MPa and 320 °C, and STY of methanol reached 0.98 g_MeOHh^-1g_cat^-1 at 350 °C. The ZnO/In₂O₃ QDs heterojunctions were formed at the interface between ZnO and In₂O₃(222). The ZnO/In₂O₃ heterojunctions, as a key structure to promote the CO₂ hydrogenation to methanol, not only enhanced the interaction between ZnO and In₂O₃ as well as CO₂ adsorption capacity, but also accelerated the electron transfer from In³⁺ to Zn²⁺. ZnO QDs boosted the dissociation and activation of H₂. The carbon layer coated on In₂O₃ surface played a role of hydrogen spillover medium, and the dissociated H atoms were transferred to the CO₂ adsorption sites on the In₂O₃ surface through the carbon layer, promoting the reaction of H atoms with CO₂ more effectively. In addition, the conductivity of carbon enhanced the electron transfer from In³⁺ to Zn²⁺. The combination of the ZnO/In₂O₃ QDs heterojunctions and carbon layer greatly improved the methanol generation activity.

Keywords: CO(2) hydrogenation to methanol; Carbon; In(2)O(3) hollow tube; ZnO QDs; ZnO/In(2)O(3) QDs heterojunctions.