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The key challenge for controlling low concentration volatile organic compounds (VOCs) is to develop technology capable of operating under mild conditions in a cost-effective manner. Meanwhile, ozone (O3) is another dangerous air pollutant and byproducts of many emerging air quality control technologies, such as plasma and electrostatic precipitators. To address these multiple challenges, we report here a design strategy capable of achieving the following trifunctions (i.e., efficiently VOCs adsorption enrichment, ozone destruction, and stable VOCs degradation) from the synergistic effect of adsorption center encapsulation and catalytic active sites optimization using 2D manganese­(II) monoxide nanosheets decorated carbon spheres with hierarchical core–shell structure. Carbonous residues in the as-synthesized MnO x matrices played a key role for in situ generating homogeneous dispersed unsaturated MnO during the annealing of the as-synthesized C@MnO x in the flow of argon under a proper calcination temperature (550 °C). The formation of the intimacy interface between MnO and carbon not only facilitates the adsorption and subsequent catalytic reaction but also results in a gatekeeper effect on the protection of the carbon sphere against the etching of O3. Such a composite architecture achieved the highest stable removal efficiency (100% for 60 ppm of formaldehyde and 180 ppm of O3 simultaneously) and 100% CO2 selectivity under a GHSV of 60000 mL h–1 g–1. These findings thus open up a way to address current multiple challenges in air quality control using a single hierarchical core–shell structure.

Well‐defined Cu2O nanocubes with tunable dimensions and physicochemical properties have been prepared using a simple one‐pot reaction. Reduction of Cu(II) salts by ascorbic acid in the presence of PEG as a structure‐directing agent affords crystalline Cu2O nanocubes of between 50 to 500 nm. Optical band gap, band energies, charge‐carrier lifetimes and surface oxidation state systematically evolve with nanocube size, and correlate well with visible light photocatalytic activity for aqueous phase phenol degradation and H2 production which are both directly proportional to size (doubling between 50 and 500 nm). HPLC reveals fumaric acid as the primary organic product of phenol degradation, and selectivity increases with nanocube size at the expense of toxic catechol. Apparent quantum efficiencies reach 26 % for phenol photodegradation and 1.2 % for H2 production using 500 nm Cu2O cubes.

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