Low-Pressure Hydrogenation of CO₂ to CH₃OH Using Ni-In-Al/SiO₂ Catalyst Synthesized via a Phyllosilicate Precursor

Abstract

The overall objective of this research is to convert the increasingly concerning CO 2 and renewable H 2 to highly demanded methanol (CH 3 OH), which creates a win− win scenario for simultaneous climate change prevention and sustainable economic development. The key to the success of this targeted CO 2 utilization technology is the development of low-pressure methanol synthesis catalysts (Ni a In b Al/SiO 2 ; a = 0−8.3, b = 0−9.1) by means of a phyllosilicate precursor, allowing for formation of well-dispersed metallic particles with an average diameter of 2.5−3.5 nm. The catalysts were characterized with various methods including ICP-OES, N 2 physisorption, XRD, SEM, TEM, TGA, H 2 TPR, DRIFTS, and XPS. The performances of the Ni a In b Al/SiO 2 catalysts and conventional catalyst were compared under various evaluation temperatures at ambient pressure. It was found that catalysts with Ni/In ratios of 0.4−0.7 showed the highest activity. Ni 3.5 In 5.3 Al/SiO 2 (NIA-0.7) with 15% metal loading was the best among the tested Ni a In b Al/SiO 2 catalysts with an activity of 0.33 mol h −1 (mol catalyst metal) −1 in comparison to the benchmark Cu/ZnO/ Al 2 O 3 (CZA) catalyst at 0.17. Several Ni a In b Al/SiO 2 catalysts also showed similar CO 2 conversions in comparison to the CZA catalyst. Infrared studies using DRIFTS determined that CO 2 hydrogenation on Ni a In b Al/SiO 2 catalysts proceeds through monodentate carbonate before further conversion to monodentate and bidentate formate. With a feed of CO/H 2 instead of CO 2 /H 2 the primary hydrocarbon product changes from methanol to propane, accompanied by a lack of formate and monodentate carbonate IR signals.

CO2 hydrogenation to high-value products via heterogeneous catalysis

“…Subsequently, a series of noble metal based catalysts, such as Ga–Pd 45 , Au–CeO X /TiO 2 46 , and Pt–MoO X /Co-TiO 2 47 , were developed to convert CO 2 to CH 3 OH at low pressure or low temperature. Similarly, Fan’s group achieved low-pressure CH 3 OH synthesis via another series of multiple-metal catalysts that included In 2 O 3 , like Ni–In–Al/SiO 2 and La–Ni–In–Al/SiO 2 , starting with a phyllosilicate precursor 3,48 , and achieving CH 3 OH STYs of above 0.011 g MeOH g cat −1 h −1 at 255 °C and 0.1 MPa.…”

Novel Heterogeneous Catalysts for CO2 Hydrogenation to Liquid Fuels

“… 63 The Ni 3.5 In 5.3 Al/SiO 2 catalyst with 15% metal loading via a phyllosilicate precursor also shows a higher conversion and a better stability, while yielding lower CH 3 OH selectivity than the conventional Cu-ZnO-Al 2 O 3 catalyst at ambient pressure. 72 The optimized metal composition and well-dispersed metal particles can be achieved by partial decomposition of the phyllosilicate, which enhances the activity for CO 2 hydrogenation. For the GaPd 2 /SiO 2 system, a much higher intrinsic activity and CH 3 OH selectivity than Cu-ZnO-Al 2 O 3 have been observed at above 200 °C and atmospheric pressure.…”

In-depth characterisation of metal-support compounds in spent Co/SiO2 Fischer-Tropsch model catalysts

“…However, no MSC compound could be detected by means of XRD analysis [19]. In-terestingly, the identified MSC was partially reducible at 420 °C and further strongly resembles phyllo-silicates, which have been synthesised as a precursor in various catalyst preparation routes [28][29][30][31][32].…”