Single atom catalysts on MXene for carbon dioxide reduction reaction

• Main Author: Lee, Daryll Shzen
• Other Authors: Lam Yeng Ming
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; MXene; Single atom catalyst; Carbon dioxide reduction; 2D nanomaterial
• Online Access: https://hdl.handle.net/10356/181556
• Institution: Nanyang Technological University

In recent years, global temperatures have risen at an accelerating rate, largely due to the effects of climate change and global warming. Carbon dioxide (CO2) is one of the primary drivers of this warming, accounting for approximately two-thirds of the temperature increase caused by human activities. As efforts to address climate change continue, reducing atmospheric CO2 levels has become a crucial focus due to its substantial role in global warming. MXenes, a relatively new class of materials similar to graphene, are two-dimensional (2D) nanomaterials with exceptional, tunable properties. These properties can be adjusted through various methods, such as modifying surface termination groups, altering layer thickness, ion intercalation, doping, and etching. Single-atom catalysts, a category of heterogeneous catalysts, contain isolated metal atoms dispersed on a support material. MXene-based single-atom catalysts use MXenes as the support material to disperse these isolated metal atoms, offering a novel approach for CO2 reduction. By converting CO2 into valuable products like methane and carbon monoxide, MXene-based single-atom catalysts represent a promising solution for lowering carbon emissions. This project investigates the potential for enhancing catalytic activity and selectivity for CO2 reduction using Nb2C MXene-based single-atom catalysts. Beginning with hydrothermally etching Nb2AlC MAX powder with in-situ hydrofluoric acid to produce Nb2C MXene, followed by delamination using dimethyl sulfoxide (DMSO). Metal atoms were then deposited onto the Nb2C MXene, and the resulting material was sprayed onto carbon paper for characterization through energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). CO2 reduction testing was conducted using in-line sampling gas chromatography. Copper and zinc were the metals that most significantly enhanced the catalytic activity and selectivity of Nb2C MXene, with copper showing a stronger effect than zinc. The results also indicate a strong selectivity dependent on applied potential, influencing the quantity of each product produced by the doped Nb2C MXene.