Spontaneous Formation of Low Valence Copper on Red Phosphorus to Effectively Activate Molecular Oxygen for Advanced Oxidation Process.

Efficient spontaneous molecular oxygen (O2) activation is an important technology in advanced oxidation processes. Its activation under ambient conditions without using solar energy or electricity is a very interesting topic. Low valence copper (LVC) exhibits theoretical ultrahigh activity toward O2. However, LVC is difficult to prepare and suffers from poor stability. Here, we first report a novel method for the fabrication of LVC material (P-Cu) via the spontaneous reaction of red phosphorus (P) and Cu2+. Red P, a material with excellent electron donating ability and can directly reduce Cu2+ in solution to LVC via forming Cu-P bonds. With the aid of the Cu-P bond, LVC maintains an electron-rich state and can rapidly activate O2 to produce ·OH. By using air, the ·OH yield reaches a high value of 423 µmol g-1 h-1, which is higher than traditional photocatalytic and Fenton-like systems. Moreover, the property of P-Cu is superior to that of classical nano-zero-valent copper. This work first reports the concept of spontaneous formation of LVC and develops a novel avenue for efficient O2 activation under ambient conditions.

Construction of a Novel Cascade Electrolysis-Heterocatalysis System by Using Zeolite-Encaged Ultrasmall Palladium Catalysts for H2 O2 Generation.

In situ generation of hydrogen peroxide (H2 O2 ) has attracted extensive attention, especially in water treatment. However, traditional anthraquinones can only produce high-concentration H2 O2 and its transportation and storage are not convenient and dangerous. Herein, an in situ and on-demand strategy to produce H2 O2 by using a cascade water electrolysis together with a heterocatalysis system is provided. Beginning with water, H2, and O2 can be generated via electrolysis and then react with each other to produce H2 O2 immediately on efficient zeolite-encaged ultrasmall Pd catalysts. Significantly, the H2 O2 generation rate in the optimized cascade system reaches up to 0.85 mol L-1 h-1 gPd -1 , overcoming most of the state-of-the-art catalysts in previous literature. The confinement effect of zeolites is not only beneficial to the formation of highly dispersed metal species, promoting the H2 O2 generation, but also inhibits the H2 O2 decomposition, enhancing the production yield of H2 O2 . In addition, the effect of electrolytes, sizes of Pd species, as well as zeolite acidity are also systematically studied. This work provides a new avenue for H2 O2 generation via a highly efficient cascade electrolysis-heterocatalysis system by using zeolite-supported metal catalysts. The high catalytic efficiency and green process for H2 O2 generation make it very promising for further practical applications.