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

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. © 2023 The Royal Society of Chemistry.