NiMn-LDH@Ti3C2(OH)2 as a new MXene-LDH nanocomposite for effective hydrogen evolution reaction in alkaline media

Abstract

The development of efficient, earth-abundant Pt-free electrocatalysts for alkaline hydrogen evolution reaction (HER) represents a significant leap forward in sustainable green energy production. In this study, the NiMn-LDH@Ti₃C₂(OH)₂ nanocomposite was synthesized for the first time through a straightforward co-precipitation method, avoiding the need for high temperatures or prolonged reaction times and employing cost-effective salts. The vertical alignment of LDH sheets on MXene layers imparts various advantageous textural properties, such as optimized electronic configuration, efficient gas diffusion, and transport on the electrocatalyst surface, prevention of aggregation and redeposition of NiMn-LDH and MXene nanosheets, significant porosity, and a multitude of exposed active sites. Considering the synergistic effects, the NiMn-LDH@MXene (5:1) structure exhibited a significant reduction of approximately 1.3 and 1.8-fold in overvoltage at a current density of 10 mA. cm⁻² compared to NiMn-LDH and MXene alone. Additionally, the obtained NiMn-LDH@MXene (5:1) structure demonstrated superior HER performance, characterized by a lower onset potential at a current density of 10 mA. cm⁻² (Ƞ₁₀ = −0.460 V/RHE), diminutive Tafel slope (220 mV. dec⁻¹), and reduced charge transfer resistance (6 Ω cm²), relative to other mass ratios of NiMn-LDH@MXene (1:1, 2:1, 3:1, 4:1). The favorable HER activity positions the NiMn-LDH@Ti₃C₂(OH)₂ synthetic strategy as a potential approach for developing electrocatalysts based on other LDH and MXene compounds, including oxygen-terminated MXenes, to enhance catalytic performance.