Zn‐Doped CeO₂ Nanorods: a Highly Efficient Heterogeneous Catalyst for the Direct Synthesis of Dimethyl Carbonate from CO₂ and Methanol

Abstract

The direct synthesis of dimethyl carbonate from methanol and CO 2 is a green and sustainable processes. In this paper, a new type of Zn-doped CeO 2 nanorods catalyst was successfully prepared by a facile hydrothermal process, and characterized by a combination of techniques including XRD, Raman, HRTEM, SEM, N 2 -sorption, CO 2 -TPD, NH 3 -TPD, XPS. The catalyst was employed as a catalyst for the synthesis of dimethyl carbonate from methanol and CO 2 . Catalytic results revealed that the Ce 1 Zn 0.1 O δ nanorods catalyst demonstrated superior catalytic activity, affording a high DMC yield of 24.2 mmol DMC /g cat , which compared favorably to other previously reported catalysts. According to the XPS and CO 2 -TPD measurements, in comparison with the pure CeO 2 nanorods, the surface oxygen vacancies and weak basic sites can be systemically enriched by introducing optimal amount of Zn dopants into CeO 2 to improve the catalytic activity for the reaction. This work establishes an efficient catalyst for the direct synthesis of dimethyl carbonate from CO 2 and methanol.[a] N.

Efficient Visible‐Light‐Assisted Synthesis of Dimethyl Carbonate from CO2 and Methanol by Ce–Metal Organic Framework‐Derived CeO2 Nanoparticles

“…Besides, the CeO 2 –M–5 possesses less moderate (at 200–400 °C) and strong (at 400–600 °C) acid–base sites than CeO 2 –C, which helps to decrease the incidence of side reactions. [ 33 ] The by‐product water not only restricts the chemical equilibrium, but also tends to adsorb on the active sites causing deactivation of catalyst. [ 34 ] As displayed in Figure 3d, the contact angle of CeO 2 –M–5 (52.5°) is higher than that of CeO 2 –C (33.4°), indicating that the water molecules are detached from the surface of CeO 2 –M–5, thus increasing the activity and stability of catalyst.…”

Recent advancements in CeO2-enabled liquid acid/base catalysis

“…On the other hand, other metals could be doped in CeO 2 to effectively modulate the geometrical and electronic structure of CeO 2 , resulting in tailored acid/base properties. 64,65 For example, the introduction of Zn atoms leads to an increase of surface oxygen vacancies, resulting in the enhancement of both acidic and basic sites with weak strength. 64 Pretreatments including chemical reduction and calcination could tune the oxygen vacancies of CeO 2 , leading to the alteration of acid/base sites as a consequence.…”

“…64,65 For example, the introduction of Zn atoms leads to an increase of surface oxygen vacancies, resulting in the enhancement of both acidic and basic sites with weak strength. 64 Pretreatments including chemical reduction and calcination could tune the oxygen vacancies of CeO 2 , leading to the alteration of acid/base sites as a consequence. 66,67 With the dedicated modulations of surface structure, the acid/base properties of CeO 2 -based materials could be precisely controlled, resulting in enhanced catalytic activity and selectivity in acid/base reactions.…”

Enabling the Methanol Economy: Opportunities and Challenges for Heterogeneous Catalysis in the Production of Liquid Fuels via Methanol

“…Doping cerium oxide with Zn also leads to the formation of oxygen vacancies, 20 which, subsequently, facilitates CO 2 activation. 21 Supporting Pd on Zn/CeO 2 provides outstanding activity for methanol synthesis from CO 2 ; 22 however, the activity of the catalyst is highly dependent on the Pd/Zn ratio. 23 A correlation was established between activity and surface basicity along with the relative content of Pd 0 (Figure 1).…”