Holes (
h
+
) on heterogeneous
photocatalysts could act as important oxidative species or precursors
for reactive oxygen species (ROS). However, due to the ultrafast recombination
of photoinduced electrons and holes, a majority of carriers are consumed
prior to surface reactions. Herein, we report an unprecedented nonphotomediated
hole oxidation system constructed from carbon nanotubes (CNTs) and
superoxides. This system exhibited high catalytic activity for the
degradation of organic pollutants, which outperforms the classical
oxidation processes in the remediation of actual wastewater and is
comparable to that of the best single cobalt atom catalyst. Theoretical
and experimental results reveal that the intrinsic defects with unpaired
spins on CNTs served as adsorptive sites to activate superoxides.
This is the first report on exploring the oxidation properties of
nonphotomediated hole carriers on heterogeneous catalysts, which will
be of broad interest for researchers in environmental remediation,
chemical synthesis, and biological fields.
The Fenton-like process catalyzed by metal-free materials presents one of the most promising strategies to deal with the ever-growing environmental pollution. However, to develop improved catalysts with adequate activity, complicated preparation/modification processes and harsh conditions are always needed. Herein, we proposed an ultrafast and facile strategy to convert various inefficient commercial nanocarbons into highly active catalysts by noncovalent functionalization with polyethylenimine (PEI). The modified catalysts could be in situ fabricated by direct addition of PEI aqueous solution into the nanocarbon suspensions within 30 s and without any tedious treatment. The unexpectedly high catalytic activity is even superior to that of the single-atom catalyst and could reach as high as 400 times higher than the pristine carbon material. Theoretical and experimental results reveal that PEI creates net negative charge via intermolecular charge transfer, rendering the catalyst higher persulfate activation efficiency.
Carbon-driven persulfate-based advanced oxidation processes have attracted extensive attentions for organic pollutant degradation in recent years. Nevertheless, the catalytic activities of carbocatalysts are still unsatisfied for practical application and the...
Highly resistant organic pollutants
and heavy metals (such as hexavalent
chromium (Cr(VI)) usually coexist in industrial wastewater. However,
efficient synergistic removal of them is still challenging in practical
applications, due to low efficiency and high energy input required
for this process. In this study, the metal-free multiwalled carbon
nanotubes (MWCNTs) are demonstrated to simultaneously remove bisphenol
A (BPA) and Cr(VI) without any external energy or chemical input.
In this novel synergistic removal system, the catalytic performance
is even higher than those of most of the reported metal-based catalysts
in photo/electrocatalytic systems. The catalytic performances are
negligibly affected by ions and humid acid, indicating applicability
of the catalyst in actual wastewater. In addition, the MWCNT catalyst
exhibits good recyclability after thermal treatment under inert atmosphere.
Furthermore, the catalytic mechanism of this system has also been
comprehensively investigated. This MWCNT-activated synergistic organic
pollutants–Cr(VI) elimination system provides a novel and cost-effective
strategy of “waste control by waste” for removing multiple
industrial contaminants.
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