Simple synthesis of nitrogen-doped porous carbon from Chinese steamed bread flour and its catalytic application for hydrogen evolution reaction

Highlights: • Green synthesis of non-metal electrocatalyst for HER using steamed bread flour. • Hydrothermal pretreatment before pyrolysis greatly enhances strength of NPCSBF. • NPCSBF exhibits HER electrocatalytic activity in acidic media. • The catalyst exhibits excellent stability and a low charge transfer resistance. • Electrocatalytic activity comparable to that of metal catalysts in acidic media. A cost-effective green synthesis method for nitrogen-doped porous carbon from Chinese steamed bread flour by successive hydrothermal treatment and pyrolysis is reported. The hydrothermal treatment remarkably enhances the strength of the resulting pyrolyzed carbon materials, enabling the facile fabrication of robust monolithic nitrogen-doped porous carbon with the yield of 44.33%. This nitrogen-doped porous carbon exhibits 3-dimensional porous structure which is mainly mesoporous and high surface area. The thin and 3-dimensional self-supported working electrode is made from the synthesized nitrogen-doped porous carbon without using any other current collector or polymeric binder. The hydrogen evolution reaction electrocatalytic activity in 0.5 M H₂SO₄ reveals the achievement of the low overpotential of ∼220 mV at 10 mA cm⁻², a Tafel slope of ∼77 mV dec⁻¹, a nearly 100% Faradaic yield, an excellent stability, and a low charge transfer resistance. The self-supported electrode exhibits higher electrocatalytic activity than the powder-state supported on graphite felt electrode. Its hydrogen evolution reaction electrocatalytic activity is better than that of the reported non-metal heteroatom-doped carbon catalysts and comparable to that of some metal catalysts in acidic media. The use of flour enables the cheap and facile fabrication of carbon electrode with tunable pore sizes and surface areas, making flour-based carbon electrodes highly promising.