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.

Co‐catalysts play a critical role in enhancing the efficiency of inorganic semiconductor photocatalysts; however, synthetic approaches to tailoring co‐catalyst properties are rarely the focus of research efforts. A photomediated route to control the dispersion and oxidation state of a platinum (Pt) co‐catalyst through defect generation in the P25 titania photocatalyst substrate is reported. Titania photoirradiation in the presence of methanol induces long‐lived surface defects which subsequently promote the photodeposition of highly dispersed (2.2 ± 0.8 nm) and heavily reduced Pt nanoparticles on exposure to H2PtCl6. The optimal methanol concentration of 20 vol% produces the highest density of metallic Pt nanoparticles. Photocatalytic activity for water splitting and associated hydrogen (H2) production under UV irradiation mirrors the methanol concentration employed during the P25 photoirradiation pretreatment, and resulting Pt loading, resulting in a common mass‐normalized H2 productivity of 3800 ± 130 mmol gPt−1 h−1. Photomediated surface defects (arising in the presence of a methanol hole scavenger) provide electron traps that regulate subsequent photodeposition of a Pt co‐catalyst over P25, offering a facile route to tune photocatalytic efficiency.

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