Fe‐Doped Porous g‐C3N4 for Electrocatalytic Hydrogen Evolution Reaction under Alkaline Conditions

What is it about?

Herein, Fe-C3N4-TU was prepared by one-step pyrolysis of melamine (MA, carbon and nitrogen sources of g-C3N4) and Fe(NO3)3∙9H2O using thiourea (TU) as a pore-forming agent. Fe-C3N4-TU exhibits a low Tafel slope of 82 mV∙dec−1 and a low overpotential of 206 mV at the current density of 10 mA∙cm−2. The good HER (Electrocatalytic hydrogen evolution reaction) catalytic performance of Fe-C3N4-TU is attributed to the high intrinsic activity of Fe‒N(ǀǀǀ) coordination structure and porous structure with the intersecting channels. The Fe‒N(ǀǀǀ) coordination structure is proved by the characterized results of the XRD, XPS, and FTIR, which originates from the strong affinity of rich pyridine N in the g-C3N4 to Fe ions. Simultaneously, the addition of TU as a pore-forming agent induces the formation of large specific surface area and mesoporous structures with large pore diameters, which facilitate the exposure of Fe-N bonds and promotes H adsorption in the HER process.

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Photo by Yoann Boyer on Unsplash

Photo by Yoann Boyer on Unsplash

Why is it important?

We present a simple method to create an extraordinary Fe‒N(ǀǀǀ) structure on g-C3N4 and expose by way of TU expansion of the specific surface area, which allows electrochemical hydrogen production with high output. The Fe-C3N4-TU displays superior HER performance with a low Tafel slope and overpotential, which were 82 mV∙dec‒1 and 206 mv (current density of 10 mA∙cm‒2), respectively. Moreover, it also exhibits low charge transfer resistance (44 Ω) and excellent stability. The results indicated Fe‒N(ǀǀǀ) coordination moiety is the main active site, which induces the catalyst to produce excellent hydrogen evolution performance. The discovery will become an important part of guiding scientific research on metal-N and C3N4-based electrocatalysts in the future to achieve high-efficiency electrocatalysis for HER.