Increasing the activity of the Cu/CuAl₂O₄/Al₂O₃ catalyst for the RWGS through preserving the Cu²⁺ ions

Abstract

Isolated Cu2+ ions actively participate in CO2 hydrogenation. The reduced Cu2+ ions form dispersed Cu sites which adsorb H2 where CuAl2O4 sites actively adsorb CO2.

Experimental and Computational Synergistic Design of Cu and Fe Catalysts for the Reverse Water–Gas Shift: A Review

“…96 Furthermore, the SiO 2 layer protected the conversion from γ-Al 2 O 3 to lower-surface α-Al 2 O 3 when the catalyst was calcined above 900 °C. 96 Hare et al tested the CO yield from CO 2 by combining a perovskite (La 0.75 Sr 0.25 FeO 3 , LSF) and SiO 2 . 146 The O 2− vacancies in the active phase promoted the CO 2 conversion, and LSF/SiO 2 yielded 200% more CO than LSF alone.…”

“…Depositing a layer of SiO 2 on the surface of the catalyst before calcination favors the exposure of the Cu sites by avoiding agglomeration, increasing the CO 2 conversion by 2–3% . The spinel structure presents O 2– vacancies on the surface due to its disordered nature, favoring CO 2 adsorption and dissociation on the surface .…”

“…The deposition of a SiO 2 layer protected Cu nanoparticle active sites on Al 2 O 3 and enhanced the activity by 10% . Furthermore, the SiO 2 layer protected the conversion from γ-Al 2 O 3 to lower-surface α-Al 2 O 3 when the catalyst was calcined above 900 °C . Hare et al tested the CO yield from CO 2 by combining a perovskite (La 0.75 Sr 0.25 FeO 3 , LSF) and SiO 2 .…”

“…29 Depositing a layer of SiO 2 on the surface of the catalyst before calcination favors the exposure of the Cu sites by avoiding agglomeration, increasing the CO 2 conversion by 2− 3%. 96 The spinel structure presents O 2− vacancies on the surface due to its disordered nature, favoring CO 2 adsorption and dissociation on the surface. 77 Furthermore, Cu−Al is a disordered structure when compared to Co−Al, which improves the conversion (∼2% for Co−Al and ∼9% for Cu−Al at 400 °C) between 250 and 400 °C despite Cu−Al having a lower surface area and a larger crystallite domain size.…”

Electroplating Sludge-Derived Multiple-Metal-Doped Spinel with Superior CO Selectivity in Reverse Water–Gas-Shift Reaction

“…If nothing is done, energy-related CO 2 emissions will reach 40 billion tons by 2040, such as CO 2 capture, sequestration, or recycling. Especially, CO 2 capture and afterward conversion to valuable products, such as fuels, provide an excellent opinion. , Among various methods, CO 2 conversion to CO via reverse water–gas-shift (RWGS) reaction attracts worldwide attention. − CO is the main component of syngas (CO and H 2 ), which is used as the raw feedstock to produce fuels and other value-added petrochemicals. However, direct thermal reduction of CO 2 is extremely energy-consuming and characterized by low CO yield. , Thus, the catalyst is designed to enhance CO selectivity and minimize CH 4 selectivity. , …”