The La(Mn, Fe)O3+λ catalyst，a novel rare earth perovskite composite oxide catalyst for catalytic combustion, was prepared by sol-gel method, which was at natural gas automobile exhaust catalytic purification, smoke gas catalytically desulfurization and other fields had broad application prospects[1-2]. The newly developed catalysts were characterized by several complementary techniques. The effects of different reaction conditions such as calcination temperature, citric acid (CA) content and ethylene glycol (EG) content on the catalytic performance of the catalyst were investigated by using low concentration methane catalytic combustion as the probe reaction. The results showed that a stable single-phase rare earth perovskite La(Mn, Fe)O3+λ catalyst could be formed after calcination at 600℃ for 3h in air atmosphere. When EG/M=1/2, CA/M=1/2, the catalyst exhibited good methane catalytic combustion activity in the middle and low temperature regions. The light-off temperature (T10) and complete conversion temperature (T90) were 363℃ and 493℃, respectively, the surface activation energy was 60~80 kJ/mol, and the catalytic activity was significantly improved. The O2-TPD and XPS characterization results showed that La(Mn, Fe)O3+λ had higher surface Mn4+, Fe3+ and more active oxygen species, which significantly improved the catalytic activity.reaction. The results showed that a stable single-phase rare earth perovskite La(Mn, Fe)O3+λ catalyst could be formed after calcination at 600℃ for 3h in air atmosphere. When EG/M=1/2, CA/M=1/2, the catalyst exhibited good methane catalytic combustion activity in the middle and low temperature regions. The light-off temperature (T10) and complete conversion temperature (T90) were 363℃ and 493℃, respectively, the surface activation energy was 60~80 kJ/mol, and the catalytic activity was significantly improved. The O2-TPD and XPS characterization results showed that La(Mn, Fe)O3+λ had higher surface Mn4+, Fe3+ and more active oxygen species, which significantly improved the catalytic activity. Keywords : perovskite ; sol-gel ; methane ; catalytic combustion ; La(Mn, Fe)O3+λ

A novel and efficient 1,2-oxidative trifluoromethylation of olefins employing Ag(O₂CCF₂SO₂F) as a trifluoromethyl source is described with O₂ as the oxidant, which provides access to a variety of valuable α-trifluoromethyl-substituted ketones. The broad substrate scope, feasibility of large-scale operation, and derivatization reactions of α-trifluoromethyl ketones demonstrate the promising utility of this protocol.

The widespread application of detonation nanodiamonds (DNDs) is limited by surface-coated non-diamond sp² carbon impurities. In this work, an efficient salt-assisted catalytic purification strategy is developed to achieve selective oxidation removal of sp² carbon. DND black powder was mixed with various chloride, carbonate, and bicarbonate salts and thermally treated in air to systematically investigate the effects of anions and cations on purification efficiency. Thermogravimetric analysis reveals that all tested salts significantly reduce the oxidation onset temperature of sp² carbon and exhibit distinct catalytic trends: for anions, bicarbonates > carbonates > chlorides; for cations, Cs⁺ ≈ K⁺ > Na⁺. Among them, KHCO₃ introduced via a wet-wrapping method shows the optimal performance, lowering the oxidation temperature by approximately 160 °C. Moreover, the wet-wrapping process effectively suppresses particle sintering and agglomeration during purification, resulting in purified DNDs with reduced average particle size and markedly improved dispersibility. Mechanistic investigations demonstrate that free alkali metal cations act as active sites, preferentially catalyzing sp² carbon oxidation through a synergistic oxygen spillover–electron transfer mechanism. This study provides an effective and highly selective approach for DND purification. The proposed salt-assisted strategy, integrating catalytic oxidation and dispersion control, also offers valuable insights for the preparation of high-performance nanomaterials.

Nano-agriculture is a fast-growing interdisciplinary field advancing from lab research to practical field application to tackle global food security and ag