Core–shell Si-doped NiFe LDH/C electrocatalyst for the methanol oxidation reaction

Abstract

Designing non-precious metal-based catalysts with high current density, high stability, and high CO tolerance is crucial for direct methanol fuel cells. NiFe-layered double hydroxides (NiFe-LDH), as a type of layered hydroxide, possess the benefits of a large specific surface area and high potential electrocatalytic performance. However, its poor conductivity, low intrinsic activity and ease of agglomeration seriously limit its application in the methanol oxidation reaction. In this paper, we report a Si-doped NiFe-LDH/C catalyst in which carbon spheres are used as the core to increase the electrical conductivity and disperse NiFe-LDH, and doping with Si further improves the intrinsic performance for the MOR by regulating the electronic structure of NiFe-LDH. The core–shell Si₂₅₀-NiFe-LDH/C has a specific activity of 154.77 mA cm⁻² and a mass activity of 911.67 mA mg⁻¹ for the methanol oxidation reaction, which is much higher than that of NiFe-LDH/C. Meanwhile, Si doping improves the tolerance to CO, and thus, Si₂₅₀-NiFe-LDH/C exhibits excellent stability for 10 hours. This work may supply new thoughts for the design of highly effective noble-metal-free catalysts for the methanol oxidation reaction.