Synergistically interactive MnFeM (M = Cu, Ti, and Co) sites doped porous g-C3N4 fiber-like nanostructures for an enhanced green hydrogen production

Abstract

The use of a synergetic effect is an effective approach for promoting the green hydrogen evolution reaction (HER). However, ternary metal doped porous g-C₃N₄ fiber-like nanostructures have not been reported so far. Herein, we synthesized ternary MnFeM (M = Cu, Ti, and Co) active sites doped porous fiber-like g-C₃N₄ nanostructures (denoted as MnFeM/g-C₃N₄ NFs) for the efficient HER. This is driven by the sluggish protonation of the melamine monomer in an aqueous solution of ethanol containing ternary metal precursors, followed by carbonization at 550 °C under N₂. The as-obtained MnFeM/g-C₃N₄ NFs were analyzed using various tools which suggest the high-yield of porous ultra-long fiber-like g-C₃N₄ (3.5–10 μm in length and 70–95 nm in width), with a large surface area (200–250 m² g⁻¹), and doped with MnFeM atoms (1.7–2.25 wt%). MnFeCu/g-C₃N₄ NFs with remarkable synergism showed the highest HER performance with an overpotential at 10 mA cm⁻² (η₁₀) of 400 mV and a H₂ production rate of 3774.35 μmol g⁻¹ h⁻¹ that were 1.8 and 4.3 times higher than those of MnFe/g-C₃N₄ NFs and Mn/g-C₃N₄ NFs. The presented results imply that higher synergism is preferred for the enhanced HER on ternary metal-doped porous g-C₃N₄ and may allow the synthesis of other ternary metal-doped porous g-C₃N₄ NFs for the electrocatalytic HER.