CO2 hydrogenation to dimethyl ether over In2O3 catalysts supported on aluminosilicate halloysite nanotubes

Alexey Pechenkin,Kirill Cherednichenko,Aleksandr Glotov,Dmitry Potemkin,Ekaterina Smirnova,Vladimir Vinokurov,Sukhe Badmaev

doi:10.1515/gps-2021-0058

Abstract

Abstract This work presents results on CO2 hydrogenation to dimethyl ether (DME) over bifunctional catalysts consisting of In2O3, supported on natural clay halloysite nanotubes (HNT), and HNT modified with Al-MCM-41 silica arrays. The catalysts were characterized by TEM, STEM, EDX-mapping, NH3-TPD, XRD, low-temperature nitrogen adsorption, TPO, and H2-TPR techniques. Catalytic properties of In2O3/HNT and In2O3/Al-MCM-41/HNT in the CO2 hydrogenation to DME were investigated in a fixed-bed continuous flow stainless steel reactor at 10–40 atm, in the temperature range of 200–300°C, at GHSV = 12,000 h−1 and molar ratio of H2:CO2 = 3:1. The best catalyst for CO2 hydrogenation was In2O3/Al-MCM-41/HNT that provided DME production rate 0.15 gDME·(gcat·h)−1 with DME selectivity 53% and at 40 bar, GHSV = 12,000 h−1, and T = 250°C. It was shown that In2O3/Al-MCM-41/HNT exhibited stable operation for at least 40 h on stream.

Highlights

This work presents results on CO2 hydrogenation to dimethyl ether (DME) over bifunctional catalysts consisting of In2O3, supported on natural clay halloysite nanotubes (HNT), and HNT modified with Al-MCM-41 silica arrays
We present novel bifunctional In2O3 catalysts supported on natural clay nanotubes (10 wt% In2O3/HNT) and composite with structured mesoporous silica (10 wt% In2O3/MCM-41/HNT) for CO2 hydrogenation to DME
Catalytic experiments on CO2 hydrogenation were studied in a fixed-bed continuous-flow stainless steel reactor

Summary

Introduction

Abstract: This work presents results on CO2 hydrogenation to dimethyl ether (DME) over bifunctional catalysts consisting of In2O3, supported on natural clay halloysite nanotubes (HNT), and HNT modified with Al-MCM-41 silica arrays. It was shown that methanol with ∼100% selectivity is achieved on bulk In2O3 at low CO2 conversions [19] These works gave an impetus to further extensive studying of catalysts on indium oxide in the hydrogenation of CO2 – the effect of various supports, preparation methods, the structure of indium oxide, and various additives on the catalytic activity [20,21,22,23,24]. Core-shell structure catalysts, such as Cu–ZnO–Al2O3@HZSM-5 [51] or CuO–ZnO–Al2O3@SiO2–Al2O3 [52], are intensively studying in direct DME synthesis from CO2 These systems prevent metal particles from sintering [53] and deactivation due coke formation by side reactions [54]. We present novel bifunctional In2O3 catalysts supported on natural clay nanotubes (10 wt% In2O3/HNT) and composite with structured mesoporous silica (10 wt% In2O3/MCM-41/HNT) for CO2 hydrogenation to DME

Synthesis and characterization of catalysts

Catalyst testing

Catalytic results

Conclusion