Highly active, ultra-low loading single-atom iron catalysts for catalytic transfer hydrogenation.

Highly effective and selective noble metal-free catalysts attract significant attention. Here, a single-atom iron catalyst is fabricated by saturated adsorption of trace iron onto zeolitic imidazolate framework-8 (ZIF-8) followed by pyrolysis. Its performance toward catalytic transfer hydrogenation of furfural is comparable to state-of-the-art catalysts and up to four orders higher than other Fe catalysts. Isotopic labeling experiments demonstrate an intermolecular hydride transfer mechanism. First principles simulations, spectroscopic calculations and experiments, and kinetic correlations reveal that the synthesis creates pyrrolic Fe(II)-plN3 as the active center whose flexibility manifested by being pulled out of the plane, enabled by defects, is crucial for collocating the reagents and allowing the chemistry to proceed. The catalyst catalyzes chemoselectively several substrates and possesses a unique trait whereby the chemistry is hindered for more acidic substrates than the hydrogen donors. This work paves the way toward noble-metal free single-atom catalysts for important chemical reactions.

Metallic Carbonitride MXene Based Photonic Hyperthermia for Tumor Therapy.

Photothermal therapy (PTT) as a noninvasive hyperthermia exhibits high potential for anti-cancer treatments. The explosion of efficient photothermal agents (PTAs) keeps developing rapidly. MXene stands out due to its intriguing structures, fantastic photodynamic properties, and good biocompatibility. However, the potential of MXenes has not been sufficiently explored in PTT. Its versatile chemical compositions of MXenes provide vast opportunities to discover new candidates. Considering that the metallic feature is mainly attributed to the metal element, anionic modulation may open a distinct avenue to propel efficient PTAs with metallic nature, which is expected for high light-harvesting over near-infrared (NIR)-I and NIR-II. As a paradigm, metal carbonitride is chosen to visualize the influences of anionic modulation. Taking advantage of electron injection from nitrogen, the distinct carbonitride Ti3 C1.15 N0.85 F0.88 O0.56 (OH)0.56 exhibits a strong NIR absorption (36.6 L g-1 cm-1 at 808 nm, 43.5 L g-1 cm-1 at 1064 nm), resulting in efficient photonic hyperthermia against tumors in vitro and in vivo. Looking through a large family of MXenes, this proof-of-principle demonstration offers a deep understanding between atomic composition and physicochemical properties, which further solidifies MXenes with all the potential for biomedical applications.

Pd-Modified ZnO-Au Enabling Alkoxy Intermediates Formation and Dehydrogenation for Photocatalytic Conversion of Methane to Ethylene.

Photocatalysis provides an intriguing approach for the conversion of methane to multicarbon (C2+) compounds under mild conditions; however, with methyl radicals as the sole reaction intermediate, the current C2+ products are dominated by ethane, with a negligible selectivity toward ethylene, which, as a key chemical feedstock, possesses higher added value than ethane. Herein, we report a direct photocatalytic methane-to-ethylene conversion pathway involving the formation and dehydrogenation of alkoxy (i.e., methoxy and ethoxy) intermediates over a Pd-modified ZnO-Au hybrid catalyst. On the basis of various in situ characterizations, it is revealed that the Pd-induced dehydrogenation capability of the catalyst holds the key to turning on the pathway. During the reaction, methane molecules are first dissociated into methoxy on the surface of ZnO under the assistance of Pd. Then these methoxy intermediates are further dehydrogenated and coupled with methyl radical into ethoxy, which can be subsequently converted into ethylene through dehydrogenation. As a result, the optimized ZnO-AuPd hybrid with atomically dispersed Pd sites in the Au lattice achieves a methane conversion of 536.0 µmol g-1 with a C2+ compound selectivity of 96.0% (39.7% C2H4 and 54.9% C2H6 in total produced C2+ compounds) after 8 h of light irradiation. This work provides fresh insight into the methane conversion pathway under mild conditions and highlights the significance of dehydrogenation for enhanced photocatalytic activity and unsaturated hydrocarbon product selectivity.