The Catalyst Review March 2020 - 16

EXPERIMENTAL
Ethane conversion, BTX selectivity, and the lifetime of the
modified samples were compared to their parent zeolites.
The results show that all the desilicated ZSM-5 zeolites loaded
with zinc exhibit higher and more stable BTX yields than their
respective conventional counterparts (Figure 2). Moreover, the
highest yield of aromatics is observed at the highest conversion
for all the catalysts. D-ZSM-5-5%Zn has the highest initial yield
of approximately 22% and the BTX yields are 18% and 14% for
D-ZSM-5-1%Zn and D-ZSM-5-0.5%Zn, respectively. After 30 hours
of reaction, no BTX is produced from ethane over the conventional
ZSM-5 with different zinc loadings, while the yield was reduced
almost 50% in all Zn-containing desilicated ZSM-5 catalysts. This
finding may confirm that despite coke formation, the active sites
in the desilicated samples are still accessible for the conversion
of ethane to BTX. Source: Goodarzi F, Thumbayil RP, EnemarkRasmussen K, et al. (2020). ChemCatChem, DOI: 10.1002/
cctc.201902123

Figure 2. Conversion of ethane (left) and BTX yield (right) for zinccontaining C-ZSM-5 and D-ZSM-5 catalysts over 30 h at 550°C, 2 barg
and GHSV=0.3 h-1.

When Nanozymes Meet Single-Atom Catalysis...
Nanozymes, nanomaterials with
enzyme-like activities, have
generated considerable attention
due to their low cost, superior
activity and high stability. Singleatom catalysts (SACs), which
are characterized by atomically
dispersed active sites, provide
excellent opportunities for mimicking
metalloprotease and for bridging
the gap between natural enzymes
and nanozymes. This minireview
illustrates the unique properties
of nanozymes and discusses
recent advances in the synthesis,
characterization and applications
of SACs. The authors then outline
progress made in single-atom
nanozymes and discuss their
applications in sensing, degradation
of organic pollutants, and in
therapeutic roles.

Figure 1. a) An illustration of the oxidase-like activity
of FeN5. b) A comparison of the oxidase properties of
MnN5, CoN5, FeN4, NiN5, and CuN5 on carbon nanoframe
(CNF). c) The durability of FeN5 treated with acid or alkali
for 21 h. d) A theoretical investigation of the oxidaselike activity over MnN5, CoN5, and FeN4. e) The Fe-N-C
SAzyme with peroxidase activity for biosensing of H2O2,
glucose, and AA.

Figure 2. The antibacterial properties of Zn-N-C
SAzymes. a) in vitro and b) in vivo. c) Zn-N-C SAzymes
employed in photodynamic/photot-hermal synergetic
therapy; near-infrared (NIR) light.

Beginning with a discussion of
single-atom catalysts, the authors
explore the implications associated
with the strong metal-support
interactions derived from interfacial
bonding, which stabilize single
atoms efficiently and play a significant role in their catalytic performance. Carbon-supported SACs (for example, M@N@C) hold
great promise in the catalysis field because they offer high surface area, good stability, flexibility with dopants, and excellent
electrical conductivity. For instance, metal-ion-doped carbon nitride, carbon dots, graphene, and metal-organic frameworks reported
previously, present high enzyme-like activity. More recently, a range of SACs have been synthesized and their enzyme-like activities
investigated in biosensing (Figure 1), environmental protection, and therapeutic roles (Figure 2).

The Catalyst Review

March 2020

The Catalyst Review March 2020

Table of Contents for the Digital Edition of The Catalyst Review March 2020