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...

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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.