Compatibility between Activity and Selectivity in Catalytic Oxidation of Benzyl Alcohol with Au-Pd Nanoparticles through Redox Switching of SnOx

Engineering of Pore Design and Oxygen Vacancy on High-Entropy Oxides by a Microenvironment Tailoring Strategy

High-entropy oxides (HEOs) exhibit abundant structural diversity due to cationic and anionic sublattices with independence, rendering them superior in catalytic applications compared to monometallic oxides. Nevertheless, the conventional high-temperature calcination approach undermines the porosity and reduces the exposure of active sites (such as oxygen vacancies, OVs) in HEOs, leading to diminished catalytic efficiency. Herein, we fabricate a series of HEOs with a large surface area utilizing a microenvironment modulation strategy (m-NiMgCuZnCo: 86 m2/g, m-MnCuCoNiFe: 67 m2/g, and m-FeCrCoNiMn: 54 m2/g). The enhanced porosity in m-NiMgCuZnCo facilitates the presentation of numerous OVs, exhibiting an exceptional catalytic performance. This tactic creates inspiration for designing HEOs with rich porosity and active species with vast potential applications.

Self-Driven Electric Field Control of Orbital Electrons in AuPd Alloy Nanoparticles for Cancer Catalytic Therapy

The free radical generation efficiency of nanozymes in cancer therapy is crucial, but current methods fall short. Alloy nanoparticles (ANs) hold promise for improving catalytic performance due to their inherent electronic effect, but there are limited ways to modulate this effect. Here, a self-driven electric field (E) system utilizing triboelectric nanogenerator (TENG) and AuPd ANs with glucose oxidase (GOx)-like, catalase (CAT)-like, and peroxidase (POD)-like activities is presented to enhance the treatment of 4T1 breast cancer in mice. The E stimulation from TENG enhances the orbital electrons of AuPd ANs, resulting in increased CAT-like, GOx-like, and POD-like activities. Meanwhile, the catalytic cascade reaction of AuPd ANs is further amplified after catalyzing the production of H2 O2 from the GOx-like activities. This leads to 89.5% tumor inhibition after treatment. The self-driven E strategy offers a new way to enhance electronic effects and improve cascade catalytic therapeutic performance of AuPd ANs in cancer therapy.

Rational Design of Highly Efficient PdIn-In2O3 Interfaces by a Capture-Alloying Strategy for Benzyl Alcohol Partial Oxidation

Well-dispersed PdIn bimetallic alloy nanoparticles (1-4 nm) were immobilized on mesostructured silica by an in situ capture-alloying strategy, and PdIn-In₂O₃ interfaces were rationally constructed by changing the In₂O₃ loading and reduction temperature. The catalytic performance for benzyl alcohol partial oxidation was evaluated, and a catalytic synergy was observed. The Pd-rich PdIn-In₂O₃ interface is prone to be formed on the catalyst with a low In₂O₃ loading after being reduced at 300 °C. It was demonstrated that the Pd-rich PdIn-In₂O₃ interface was more active for benzyl alcohol partial oxidation than In-rich Pd₂In₃ species, which was likely to be formed at a high reduction temperature (400 °C). The high catalytic activity on the Pd-rich PdIn-In₂O₃ interface was attributed to the exposure of more Pd-enriched active sites, and an optimized PdIn-In₂O₃/Pd assemble ratio enhanced the oxygen transfer during partial oxidation. The density functional theory (DFT) calculation confirmed that the Pd-rich Pd₃In₁(111)-In₂O₃ interface facilitated the activation of oxygen molecules, resulting in high catalytic activity.

Promotion of the Co3O4/TiO2 Interface on Catalytic Decomposition of Ammonium Perchlorate

Supports can widely affect or even dominate the catalytic activity and selectivity of nanoparticles because atomic geometry and electronic structures of active sites can be regulated, especially at the interface of nanoparticles and supports. However, the underlying mechanisms of most systems are still not fully understood yet. Herein, we construct the interface of Co₃O₄/TiO₂ to boost ammonium perchlorate (AP) catalytic decomposition. This catalyst shows enhanced catalytic performance. With the addition of 2 wt % Co₃O₄/TiO₂ catalysts, AP decomposition peak temperature decreases from 435.7 to 295.0 °C and activation energy decreases from 211.5 to 137.7 kJ mol^-1. By combining experimental and theoretical studies, we find that Co₃O₄ nanoparticles can be strongly anchored onto TiO₂ supports accompanied by charge transfer. Moreover, at the interfaces in the Co₃O₄/TiO₂ nanostructure, NH₃ adsorption can be enhanced through hydrogen bonds. Our research studies provide new insights into the promotion effects of the nanoparticle/support system on the AP decomposition process and inspire the design of efficient catalysts.

Boosting the catalytic behavior and stability of a gold catalyst with structure regulated by ceria

In this work, a series of colloidal gold nanoparticles with controllable sizes were anchored on carbon nanotubes (CNT) for the aerobic oxidation of benzyl alcohol. The intrinsic influence of Au particles on the catalytic behavior was unraveled based on different nanoscale-gold systems. The Au/CNT-A sample with smaller Au sizes deserved a faster reaction rate, mainly resulting from the higher dispersion degree (23.5%) of Au with the available exposed sites contributed by small gold particles. However, monometallic Au/CNT samples lacked long-term stability. CeO2 was herein decorated to regulate the chemical and surface structure of the Au/CNT. An appropriate CeO2 content tuned the sizes and chemical states of Au by electron delivery with better metal dispersion. Small CeO2 crystals that were preferentially neighboring the Au particles facilitated the generation of Au-CeO2 interfaces, and benefited the continuous supplementation of oxygen species. The collaborative functions between the size effect and surface chemistry accounted for the higher benzaldehyde yield and sustainably stepped-up reaction rates by Au-Ce5/CNT with 5 wt% CeO2.