posted on 2020-05-11, 13:07authored bySayed
M. El-Refaei, Patrícia A. Russo, Patrick Amsalem, Nobert Koch, Nicola Pinna
Coordination
polymers (CPs) and metal–organic frameworks
(MOFs) have emerged as versatile precursors for transition-metal phosphides
catalysts. However, the controlled synthesis of CPs-derived bimetallic
phosphides remains a challenge, as mixtures of various phosphide phases
are often formed. Here, it is shown that controlling the formation
of pure CoMoP and CoMoP2 nanoparticles requires a careful
choice of the ligands used to construct the precursors based on the
chemical properties of the metals. In particular, the nature and number
of the coordination moieties of the ligand play key roles. CoMoP and
CoMoP2 particles coated with N-doped carbon were derived
from phosphonate-based CPs and compared as hydrogen evolution reaction
(HER) electrocatalysts in acidic medium. CoMoP2 is more
active and shows a turnover frequency (TOF) of 0.9 s–1 compared to 0.4 s–1 for CoMoP. The higher intrinsic
activity of the CoMoP2 catalytic sites correlates with
the differences in the electronic structure of the materials, with
a larger charge transfer from the molybdenum to the phosphorus found
for CoMoP2.