Rapid Joule Heating Synthesis of Oxide-Socketed High-Entropy Alloy Nanoparticles as CO₂ Conversion Catalysts

Abstract

The unorthodox surface chemistry of highentropy alloy nanoparticles (HEA-NPs), with numerous interelemental synergies, helps catalyze a variety of essential chemical processes, such as the conversion of CO 2 to CO, as a sustainable path to environmental remediation. However, the risk of agglomeration and phase separation in HEA-NPs during high-temperature operations are lasting issues that impede their practical viability. Herein, we present HEA-NP catalysts that are tightly sunk in an oxide overlayer for promoting the catalytic conversion of CO 2 with exceptional stability and performance. We demonstrated the controlled formation of conformal oxide overlayers on carbon nanofiber surfaces via a simple sol−gel method, which facilitated a large uptake of metal precursor ions and helped to decrease the reaction temperature required for nanoparticle formation. During the rapid thermal shock synthesis process, the oxide overlayer would also impede nanoparticle growth, resulting in uniformly distributed small HEA-NPs (2.37 ± 0.78 nm). Moreover, these HEA-NPs were firmly socketed in the reducible oxide overlayer, enabling an ultrastable catalytic performance involving >50% CO 2 conversion with >97% selectivity to CO for >300 h without extensive agglomeration. Altogether, we establish the rational design principles for the thermal shock synthesis of high-entropy alloy nanoparticles and offer a helpful mechanistic perspective on how the oxide overlayer impacts the nanoparticle synthesis behavior, providing a general platform for the designed synthesis of ultrastable and high-performance catalysts that could be utilized for various industrially and environmentally relevant chemical processes.

Synthesis of metallic high-entropy alloy nanoparticles

“…Ahn and co-workers tackled this issue by adding a thin titanium (TiO 2 ) layer that conformally coats the carbon fiber surfaces, preventing direct contact between metals and carbon. 78 Because of the thin thickness, the TiO 2 coating does not turn off the carbothermal shock function of the carbon fibers for high-temperature synthesis of HEA nanoparticles. Fig.…”

Cu-based catalyst designs in CO2 electroreduction: precise modulation of reaction intermediates for high-value chemical generation

“…valuable chemical products. [18][19][20][21][22][23][24][25][26][27][28] With the utilization of renewable energy sources, ECR has emerged as a promising avenue for converting CO 2 into value-added multi-carbon products, facilitating the attainment of carbon neutrality (Fig. 1).…”

“…8–17 Over the past few decades, scientists have diligently pursued the development of advanced technologies that enable the environmentally friendly conversion of CO 2 into valuable chemical products. 18–28 With the utilization of renewable energy sources, ECR has emerged as a promising avenue for converting CO 2 into value-added multi-carbon products, facilitating the attainment of carbon neutrality (Fig. 1).…”

Highly Stable Single-Phase FeCoNiMnX (X = Cr, Mo, W) High-Entropy Alloy Catalysts with Submicrometer Size for Efficient Oxygen Evolution

“…), 20,21 which will result in significant phase separation and segregation in the alloy. 22,23 Second, reducing the particle size of HEAs is difficult because the long preparation time and high temperature (higher than mp) result in the growth of the particles. 24 Moreover, an extreme cooling rate is required, and the multistep preparation process increases the synthesis complexity and costs.…”

“…First, the preparation of uniform HEAs consisting of elements with great disparity in physicochemical properties (i.e., density (ρ), melting point ( mp ), atomic radius ( r ), electronegativity (χ), and mixing enthalpy (Δ H ), etc. ), , which will result in significant phase separation and segregation in the alloy. , Second, reducing the particle size of HEAs is difficult because the long preparation time and high temperature (higher than mp ) result in the growth of the particles . Moreover, an extreme cooling rate is required, and the multistep preparation process increases the synthesis complexity and costs .…”