Porphyrinic Metal-Organic Frameworks Derived Carbon-Based Nanomaterials for Hydrogen Evolution Reaction

Hydrogen is a renewable, secure and environmentally friendly source of energy, and thus it is important to find an effective way to prepare hydrogen evolution reaction (HER) catalysts. Herein, we report a strategy to prepare noble metal-decorated porous carbon-based nanomaterials by direct carbonization of porphyrinic metal-organic frameworks of M-PCN-222(Hf) that are also denoted as M-PMOF-2(Hf) (M=Rh, Ir or Pt) at an elevated temperature under an Ar atmosphere. The M-PCN-222(Hf) samples with the nanorod shape are synthesized by the self-assembly of M-TCPP (TCPP=tetrakis(4-carboxyphenyl)porphyrin) and HfCl4, and the noble metals within the frameworks are uniformly dispersed at the atomic level. Through pyrolysis at 600, 700 or 800 degrees C and followed by acid etching with HF, noble metal-decorated porous carbon-based nanomaterials that are termed as M-PCN-222(Hf)-T (T is the pyrolysis temperature) are obtained, in which the noble metal nanoparticles are dispersed uniformly within the porphyrin ligand-derived nitrogen-doped carbon matrix. Inheriting the structural characteristics of the MOF template, M-PCN-222(Hf)-T display relatively high BET surfaces up to 310 m(2).g(-1)and large mesopores with an average pore diameter around 6 nm. Catalytic results show that the prepared M-PCN-222(Hf)-T samples display high HER catalytic activities in a 0.5 M H(2)SO(4)solution (pH=0.36).