FeCo Alloy Nanoparticles Supported on N-doped Mesoporous Carbon Spheres for Hydrogen Evolution and Reduction of Organic Dyes

Abstract

The catalytic activity of FeCo alloy nanoparticles (NPs) supported on nitrogen-doped mesoporous carbon spheres (FeCo/NMCS) was evaluated for hydrogen evolution and reduction of various organic dyes. The NMCS was spherical, with an average diameter of 488.1 nm, while the FeCo alloy NPs were evenly distributed across the NMCS, with an average diameter of 8.2 nm. The nitrogen content in FeCo/NMCS was found to be 3.91 wt%. The FeCo/NMCS displayed remarkable efficiency in hydrogen evolution through the hydrolysis of ammonia borane (AB), characterized by an activation energy of 23.49 kJ/mol. The FeCo/NMCS also demonstrated superior catalytic activity in reducing 4-nitrophenol (4-NP), with a reduction rate constant of 0.468 min⁻¹ using 5 mg of FeCo/NMCS and 20 mg of AB. This rate places the FeCo/NMCS among the highest-performing catalysts for 4-NP reduction. Further, the catalyst efficiently reduced crystal violet, methylene blue, and rhodamine B under the same conditions. Azo dyes, including tartrazine, methyl orange, Red 195, and Yellow 145, underwent faster reduction than other tested dyes. The FeCo/NMCS maintained its integrity and activity even after four hydrogen generation cycles. These results highlight FeCo/NMCS’s potential as a multifunctional, magnetically separable, and reusable catalyst for efficient hydrogen production and environmental remediation applications.