Preparation of Pt/γ-Bi2MoO6 Photocatalysts and Their Performance in α-Alkylation Reaction under Visible Light Irradiation

Boosting Photocatalytic Nitrogen Fixation via Nanoarchitectonics Using Oxygen Vacancy Regulation in W-Doped Bi2MoO6 Nanosheets

Ammonia and nitrates are key raw materials for various chemical and pharmaceutical industries. The conventional methods like Haber-Bosch and Ostwald methods used in the synthesis of ammonia and nitrates, respectively, result in harmful emission of gases. In recent years, the photocatalytic fixation of N2 into NH3 and nitrates has become a hot topic since it is a green and cost-effective approach. However, the simultaneous production of ammonia and nitrates has not been studied much. In this regard, we have synthesized W-doped Bi2MoO6 nanosheets in various molar ratios and demonstrated their potential as efficient photocatalysts for the simultaneous production of NH3 and NO3- ions under visible light irradiation. It was found that one of the catalysts (BMWO0.4) having an optimal molar ratio of doped tungsten showed the best photocatalytic NH3 production (56 μmol h-1) without using any sacrificial agents along with the simultaneous production of NO3- ions at a rate of 7 μmol h-1. The enhanced photocatalytic activity of the synthesized photocatalysts could be ascribed to oxygen vacancy defects caused by Mo substitution by a more electronegative W atom. Furthermore, density functional theory calculations verified the alteration in the band gap after doping of W atoms and also showed a strong chemisorption of N2 over the photocatalyst surface leading to its activation and thereby enhancing the photocatalytic activity. Thus, the present work provides insights into the effect of structural distortions on tailoring the efficiency of materials used in photocatalytic N2 fixation.

Enhancement of sonodynamic treatment of ovarian cancer based on Pt-B-P ternary nanoparticles

Sonodynamic therapy (SDT) can noninvasively focus sound energy to deep tumor tissues and activate sonosensitizer (such as chlorin e6(Ce6)) to produce antitumor effects. However, due to the hypoxic microenvironment of the tumor, the effect of sonodynamic therapy is limited. In this work, we successfully synthesized Platinum-Boron-Phosphorus ternary nanoparticles (Pt-B-P NPs) for the first time to efficiently catalyze the decomposition of hydrogen peroxide (H₂O₂) in tumor tissues to produce sufficient oxygen (O₂) and improve the effect of sonodynamic treatment of ovarian cancer. In vitro studies, we found that compared with Platinum nanoparticles (Pt NPs), Pt-B-P NPs have the significantly increased ability to catalyze the decomposition of H₂O₂ to produce oxygen and thus the hypoxic environment of tumor cells could be improved efficiently. Meanwhile, the bio-distribution, therapeutic effect and bio-safety of Pt-B-P NPs in vivo were evaluated using BALB/c-nu mouse model of ovarian cancer and the desired result had been achieved.

Catalytic performance and mechanism of bismuth molybdate nanosheets decorated with platinum nanoparticles for formaldehyde decomposition at room temperature

Catalytic oxidation at room temperature is considered as a promising strategy for removal of formaldehyde (HCHO), a widely occurring indoor air pollutant. A series of Bi₂MoO₆ nanosheets were prepared via one-step hydrothermal synthesis in this study, followed by decoration with Pt nanoparticles (NPs). The catalyst with Bi₂MoO₆ support prepared at 180 °C exhibited high and stable activity in catalytic oxidation of HCHO at room temperature. The excellent catalytic performance was attributed to its large specific area and pore volume, high level of surface active oxygen species, high content of metallic Pt NPs, and abundant oxygen vacancies. The good synergy and interaction between Pt and Bi₂MoO₆ promoted electron transfer, and facilitated the adsorption and oxidation of HCHO. The electronic interaction between Pt NPs and Bi₂MoO₆ accelerated the activation of oxygen species due to weakening of the surface BiO or MoO bonds adjacent to Pt NPs. Infrared spectra indicated that dioxymethylene and formate species were the main intermediates of HCHO oxidation. Density functional theory calculations showed that the dehydrogenation of HCO₂, with an energy barrier of 282.1 kJ/mol, was the rate-determining step in catalytic oxidation process. This study provides new insights on the construction of high-efficiency catalysts for indoor formaldehyde removal.