Capsule‐Structured Copper–Zinc Catalyst for Highly Efficient Hydrogenation of Carbon Dioxide to Methanol

Abstract

To develop a new and efficient CO2‐to‐methanol catalyst is of extreme significance but still remains a challenge. Herein, an innovative indirect two‐step strategy is reported to synthesize a highly efficient capsule‐structured copper‐based CO2‐to‐methanol catalyst (CZA‐r@CZM). It consists of a structurally reconstructed millimeter‐sized Cu/ZnO/Al2O3 core (CZA‐r) with intensified Cu–ZnO interactions, which is made by a facile hydrothermal treatment in an alkaline aqueous solution, and a Cu/ZnO/MgO (CZM) shell prepared by an ethylene glycol‐assisted physical coating method. The CZA‐r core displays 2.7 times higher CO2 hydrogenation activity with 2.0 times higher CO selectivity than the previously reported Cu/ZnO/Al2O3 (CZA‐p), whereas the CZM shell can efficiently catalyze hydrogenation of the as‐formed CO from the CZA‐r core to methanol as it passes through the shell. As a result, the developed capsule‐structured CZA‐r@CZM catalyst exhibits 2.4 times higher CO2 conversion with 1.8 times higher turnover frequency and 2.3‐fold higher methanol space–time yield than the CZA‐p catalyst (729.8 vs. 312.6 gMeOH kgcat−1 h−1). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) experiments reveal that the CO2 hydrogenation reaction proceeds through a reverse water–gas shift reaction followed by a CO hydrogenation pathway via an *H3CO intermediate. This work not only produces an efficient CO2‐to‐methanol catalyst, but also opens a new avenue for designing superior catalysts for other consecutive transformations.

Catalytic Conversion of Carbon Oxides in Confined Spaces: Status and Prospects

“…As a result, the 11.7 % CO 2 conversion with 73.0 % methanol selectivity is achieved. [112] This work not only develops an efficient CO 2 -to-methanol catalyst, but also paves a new way for designing other superior catalysts for diverse consecutive transformations.…”

Advances in the Design of Heterogeneous Catalysts and Thermocatalytic Processes for CO2 Utilization

“…104 Based on this study, major focus has been given to Cu-based catalysts, mainly Cu-Zn combinations. [105][106][107][108][109]…”

“…In fact, more than 75% of catalysts studied in the last 10–15 years contain copper as an active metal phase. , In the 1960s, Imperial Chemical Industries developed a highly active ternary phase Cu–ZnO–Al 2 O 3 catalyst for the selective production of methanol from naphtha and natural gas under mild conditions . Based on this study, major focus has been given to Cu-based catalysts, mainly Cu–Zn combinations. − …”

Synthesis, Types, and Applications of Zeolite Capsule Catalysts

“…For example, the bifunctional catalyst (Cr 2 O 3 /HZSM-5@Silicalite-1) not only did not deactivate, but also realized the target synthesis of BTX (benzene, toluene, and xylene), especially p-xylene (PX). [136,123] Gao et al used a solvent-free method to prepare Na-FeMn/HZSM-5@Silicalite-1 not only to solve the contamination problem of organic reagents in the synthesis process, [95] but also to enhance the yield of PX by using the low acidity and selective shape of the shell, which accounted for 81.1% of all xylene products, providing a valuable way for the efficient conversion of CO 2 hydrogenation to paraxylene. It provides a reference pathway for the efficient conversion of CO 2 hydrogenation to paraxylene.…”