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We report a noble-metal-free photocatalyst, ultrathin TiO2 with atomic layer thickness, which is a potential catalyst for CO2 photoreduction. An excellent liquid-product yield of 463.9 μmol gcat−1 in 8 h with 98% selectivity to alcohols was achieved, owing to sufficient surface defects favoring CO2 adsorption/activation. [ABSTRACT FROM AUTHOR]

Single‐atom alloys (SAAs) have ignited a surge of unprecedented interest as the advanced nanomaterials and opened many opportunities for wide applications. Herein, 3D porous aerogels comprising ionic liquid (IL) functionalized PdBi SAA building blocks with atomically dispersed Bi on Pd nanowires (IL/Pd50Bi1) are synthesized with accelerated gelation kinetics, which could serve as high‐efficiency electrocatalysts for ethanol oxidation reaction (EOR). Benefiting from the unique structures of aerogels including synergistic effects of PdBi SAA nanowire networks and interface engineering, the optimized IL/Pd50Bi1 aerogels display a nearly fourfold enhancement in mass activity and boosted stability for EOR compared to commercial Pd/C. Density functional theory calculations further demonstrate that isolated Bi atoms on Pd nanowire networks decrease the energy barrier of the rate‐determining step, resulting in excellent electrocatalytic activity for EOR. This work provides a promising method for developing efficient SAA catalysts for fuel electrooxidation. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting is a promising method to produce clean and renewable energy, which provides an alternative solution to solve environmental and resource problems. New catalysts based on semiconductor nanoparticles have received increasing attention since they facilitate all the reactions needed for "artificial photosynthesis". In recent decades, hollow microspheres have provided an ideal platform for efficient utilization. Scientists are working to understand the basic principles, band structures, and modification strategies of hollow microspheres to enhance photocatalytic performance. In this paper, the research progress of hollow microsphere photocatalysts in the field of water splitting is reviewed. In particular, the photocatalytic principles of hollow microspheres and the methods to improve the performance of semiconductor photocatalysts are discussed in depth. The structural advantages and defects of hollow microspheres and modification methods of semiconductor band structure are introduced. Finally, the remaining challenges are summarized, and some insights into new trends and improvement directions for hollow materials are provided. This review will provide new insights for understanding hollow microspheres and help researchers in related fields to have a deeper and more comprehensive understanding of hollow microspheres in photocatalytic water splitting. [Display omitted] • Hydrogen is one of the most promising renewable and clean energy sources. • Recombination of electrons and holes reduces photocatalytic efficiency. • The advantage of hollow structure for photocatalytic water splitting was reviewed. • Strategy to improve the catalytic efficiency of hollow microspheres was proposed. [ABSTRACT FROM AUTHOR]

Highlights: Secondary-atom-doped strategy was proposed to synthesize single-atom electrocatalyst. The increase in both the density of active sites and their intrinsic activity was achieved simultaneously. The resultant single-atom catalyst shows outstanding ORR activity in acidic media. Single-atom catalysts (SACs) with nitrogen-coordinated nonprecious metal sites have exhibited inimitable advantages in electrocatalysis. However, a large room for improving their activity and durability remains. Herein, we construct atomically dispersed Fe sites in N-doped carbon supports by secondary-atom-doped strategy. Upon the secondary doping, the density and coordination environment of active sites can be efficiently tuned, enabling the simultaneous improvement in the number and reactivity of the active site. Besides, structure optimizations in terms of the enlarged surface area and improved hydrophilicity can be achieved simultaneously. Due to the beneficial microstructure and abundant highly active FeN5 moieties resulting from the secondary doping, the resultant catalyst exhibits an admirable half-wave potential of 0.81 V versus 0.83 V for Pt/C and much better stability than Pt/C in acidic media. This work would offer a general strategy for the design and preparation of highly active SACs for electrochemical energy devices. [ABSTRACT FROM AUTHOR]

A novel CeO 2 /TiO 2 -MoO 3 (Ce/TM) catalyst was synthesized by using of Mo as a bulk dopant to boost the NH 3 -SCR performance of CeO 2 /TiO 2 catalyst. It displayed 100% NO conversion at 200–350 °C under 60,000 mlg −1  h −1 and high tolerance to H 2 O and SO 2 at 250 °C. Characterization results manifested that the doping of Mo not only resulted in more Brønsted acid and Lewis acid sites formed on the Ce/TM surface, but also increased the specific surface area and redox ability of the catalyst, all of which account for the enhanced NH 3 -SCR activity. [ABSTRACT FROM AUTHOR]

• Unique surface structures of Pd/TiO 2 catalysts for indoor toluene reduction. • Synergistic Pd0 and surface defects boost toluene photocatalytic oxidation. • Enhanced Ti3+/oxygen defects and Pd-TiO 2 interaction promote ROS generation. • Unique Pd/TiO 2 -N affects toluene partial oxidation and ring-opening process. Indoor volatile organic compounds (VOCs), represented by toluene, can pose a serious threat to human health. In this work, a series of Pd/TiO 2 catalysts with different surface structures (i.e. , dispersion/valence of Pd species, surface Ti3+/oxygen defect concentration and Pd-TiO 2 interactions, etc.) was constructed by various methods. It was found that the Pd/TiO 2 catalyst prepared by one-step reduction of NaBH 4 method (Pd/TiO 2 -N) with metallic Pd particles possessed more surface Ti3+/oxygen defects and stronger Pd-TiO 2 interaction than Pd/TiO 2 catalysts prepared by ethylene glycol reduction loading method (Pd/TiO 2 -E) and incipient wetness impregnation method (Pd/TiO 2 -I). Further photochemical characterizations and reaction mechanism study revealed that the relatively higher concentration of Pd0 species on Pd particles, stronger Pd-TiO 2 interaction, and more surface Ti3+/oxygen defects on Pd/TiO 2 -N could facilitate the generation of more reactive oxygen species (ROS) under light irradiation. The partial oxidation of toluene to benzyl alcohol/benzaldehyde/benzoic acid and the subsequent ring-opening process were found to be highly determined by the valence states of Pd particles and the concentration of surface Ti3+/oxygen defects. This work provides instructive insights into the construction of highly efficient Pd/TiO 2 catalysts for the removal of indoor VOCs. [ABSTRACT FROM AUTHOR]

Rational design and construction of electrochemical sensing platforms with high sensitivity and selectivity is one of the challenges in practical application. Although single-atom catalysts (SACs) have attracted extensive attention, atomically dispersed metal catalysts (ADCs) with multi-atom sites can further compensate for the deficiencies of SACs, which have gradually been a research hotspot in recent years. Herein, atomically dispersed Ru 3 site catalyst (Ru 3 /NC) is employed to catalyze small biomolecule oxidation, which exhibits much superior electrocatalytic ability of uric acid (UA) to Ru single-atom catalyst (Ru 1 /NC). What's more, theoretical calculations reveal that the enhanced performance is mainly derived from the dominant electronic structure of ADCs with multi-atom sites compared to SACs, leading to the more favorable adsorption of hydroxy anion groups, which can serve as one part of the active moiety and "promoter" to achieve the fast oxidation of small biomolecules. Our findings provide a new paradigm for designing promising catalysts to realize highly sensitive and selective small biomolecule detection and explore the catalytic mechanisms of small biomolecules at the atomic scale. [Display omitted] [ABSTRACT FROM AUTHOR]