Preparation of Integrated CuO/ZnO/OS Nanocatalysts by Using Acid-Etched Oyster Shells as a Support for CO₂ Hydrogenation

Abstract

The oyster shell (OS) is a typical biomineralized material from nature containing a large quantity of CaCO3 (approximately 96.23 wt %), which has been extensively used as a template/precursor for fabricating various functional nanomaterials. However, the matrix proteins in the uncalcified layer of the OS structure (approximately 3.75 wt %) are largely ignored during the utilization. In this regard, herein, we focused on the chemical pretreatment of the OS by hydrolysis of matrix proteins with different saturated fatty acids. The obtained acid-etched OS (a-OS) with rich coordination sites (−COOH and −NH2) was then used as a support to load Cu­(Zn)-BTC nanoparticles. In particular, a rationally designed Cu­(Zn)-BTC/a-OS was synthesized by mixing the a-OS with the precursor solutions under the complexation between the exposed functional groups and the transition-metal ions (Cu2+ and Zn2+). We also prepared CuO/ZnO/a-OS catalysts by calcining Cu­(Zn)-BTC/a-OS in air, and their workability was examined in the catalytic CO2 hydrogenation reaction. Interestingly, the CO2 conversion over CuO/ZnO/a-OS increased from 1.9 to 6.6% as compared with CuO/ZnO/OS, and the methanol yield increased from 1.3 to 4.2%. We demonstrated that the acidity and chemical structure of the saturated fatty acids played a comprehensive role in determining the hydrolysis of matrix proteins of the OS (viz., etching degree), which significantly affected the catalytic activity. It was found that the activity of a-OS-supported catalysts increased in the following sequence: benzoic acid < dodecanoic acid < acetic acid < palmitic acid < stearic acid. Accordingly, we have developed an efficient and green route to prepare supported CuO/ZnO nanocatalysts by using the cheap and ecofriendly OS powder as a support.

Pd Supported on MIL-68(In)-Derived In2O3 Nanotubes as Superior Catalysts to Boost CO2 Hydrogenation to Methanol

“…Undoubtedly, the current energy sources (coal, fossil fuels, and natural gas) are nonrenewable and how to utilize alternative carbon sources to maintain a sustainable economy has become an urgent issue . Converting CO 2 into value-added chemicals or fuels has attracted extensive research efforts in recent years. − Methanol (CH 3 OH) is an important chemical feedstock and can be used as a key intermediate to produce many other high-value chemicals, including light olefins, aromatics, dimethyl ether, and so forth . Currently, almost all synthetic methanol in the industry (50 Mt year –1 ) are produced from syngas (H 2 /CO, e.g., from coal by gasification technology) in the presence of CO 2 in which the equilibrium yield of methanol is highly dependent on the concentration of CO. , Hence, if CO 2 can be used as a sole carbon source to produce methanol, it will have significant economic and social implications.…”

In Situ Catalytic Pyrolysis of Municipal Sewage Sludge under Calcined Copper Slag: Thermokinetic Analysis and Real-Time Monitoring of Evolved Gases

“…12 As the content of Fe in CS is considerable, 16 air calcination of CS can produce Fe 2 O 3 as an Fe-based OC for CLG of SS. 17 NiO, 16 CaO, 18 and CuO 19 in CS also have catalytic and synergistic effects on the thermochemical conversion of SS. Therefore, CS as an OC source for the CLG of SS has a great potential for recycling of both SS and CS.…”

Hydrogenation of CO2 to Dimethyl Ether over Tandem Catalysts Based on Biotemplated Hierarchical ZSM-5 and Pd/ZnO

“…Global warming caused by the increased anthropogenic CO 2 emissions has become a worldwide concern. , As a matter of fact, CO 2 has been utilized as an alternative abundant feedstock for the synthesis of valuable chemicals and fuels which not only bring great economic benefits but also alleviate environmental concern. − For instance, the direct hydrogenation of CO 2 to diverse C 1 chemicals, including methanol, CO, and CH 4 , is one of the most promising routes for CO 2 utilization . Among them, CO 2 hydrogenation to methanol has received much more attention as methanol can be further transformed to other high value-added chemicals such as dimethyl ether (DME), olefins, aromatics, and so forth …”