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Pt Nanoparticles Supported on Mesoporous Graphitic Carbon Nitride as Catalysts for Hydrolytic Dehydrogenation of Ammonia Borane
journal contribution
posted on 2020-07-02, 15:00 authored by Merve Aksoy, Önder MetinPlatinum (Pt) nanoparticles
(NPs) supported on mesoporous graphitic
carbon nitride (mpg-CN/Pt) were synthesized in situ via the reduction
of as-prepared mpg-CN/Pt(IV) composites during the catalytic hydrolysis
of ammonia-borane (AB) under the white-light irradiation. The yielded
mpg-CN/Pt nanocatalysts were characterized by using many advanced
analytical techniques including TEM, XRD, ICP-MS, XPS, FTIR, PL, and
time-resolved emission spectroscopy (TRES) techniques. Besides the
privilege advantageous of the presented in situ synthesis protocol
for the synthesis of mpg-CN/Pt nanocatalysts, formation of the heterojunction
between in situ generated Pt NPs and visible-light active semiconductor
mpg-CN enables an improved charge separation and prolonged lifetime,
resulting in 2.25-fold enhanced photocatalytic activity within the
hydrolysis of AB under white-light irradiation. The effect of Pt loading
on the catalytic activity of mpg-CN/Pt nanocatalysts was examined
in the hydrolysis of AB and the highest turnover frequency (TOF) of
274.2 min–1 was obtained with 5.94 wt % Pt-loaded
mpg-CN/Pt nanocatalysts, which is the one of the best TOFs among monometallic
Pt-based nanocatalysts and comparable to the ones reported using bimetallic
Pt nanocatalysts. Moreover, mpg-CN/Pt nanocatalysts were found to
be highly durable in the hydrolysis of AB such that it preserves 78%
of its initial catalytic activity after the 10th consecutive runs,
which is one of the highest reusability performances among all Pt-based
catalysts that have been tested in the hydrolysis of AB so far. Upon
the results of the kinetic studies, the rate law and activation parameters
for the mpg-CN/Pt-catalyzed AB hydrolysis were also reported. This
work demonstrates for the first time that mpg-CN is a proper support
material for the in situ synthesis of catalytically active yet stable
Pt NPs promoting the photocatalytic hydrogen evolution from the hydrolysis
of AB.