MoO 3 with Pt-like d-band center electronic structure is an ideal catalyst carrier, but its low conductivity, wide-bandgap and poor photoresponse limits the application of photoelectrocatalysis. Designing doping and oxygen vacancies simultaneously in MoO 3 is a candidate strategy to address some challenges. Herein, a 2D oxygen-vacancies Ce-MoO 3 /Pt (OVs-Ce-MoO 3 /Pt) nanosheet is developed using a two-step method of hydrothermal and chemical reduction. The band gap, optical properties, and methanol adsorption capacity of MoO 3 are well regulated after Ce doping and oxygen vacancy introduction. Profiting by the synergistic promotion of sufficient oxygen vacancies and Ce element, the OVs-Ce-MoO 3 /Pt catalyst exhibits super-efficient photoelectrocatalytic activity (2858 mA mg −1 ) and poisoning-tolerance ability towards methanol oxidation, which is superior to the Ovs-MoO 3 /Pt catalyst (1542 mA mg −1 ) and commercial JM Pt/C catalyst (377 mA mg −1 ). These results indicate that the OVs-Ce-MoO 3 /Pt catalyst can serve as a highly promising catalyst in the field of photoelectrocatalysis.
Wang Shulong,Huang Wenfang,Lin Qingyan,Feng Yinyin,Wei Qingmin,Xu Jiayao,Wang Rong,Luo Zhihui
Nanocatalytic medicine, which aims to accurately target and effectively treat tumors through intratumoral in situ catalytic reactions triggered by tumor-specific environments or markers, is an emerging technology. However, the relative lack of catalytic activity of nanoenzymes in the tumor microenvironment (TME) has hampered their use in biomedical applications. Therefore, it is crucial to develop a highly sensitive probe that specifically responds to the TME or disease markers in the TME for precision diagnosis and treatment of diseases. In this work, a chiral photoacoustic (PA) nanoprobe (D/L-Ce@MoO 3 ) based on the H 2 O 2 -catalyzed TME activation reaction was constructed in a one-step method using d -cysteine (D-Cys) or l -cysteine (L-Cys), polymolybdate, and cerium nitrate as raw materials. The designed and synthesized D/L-Ce@MoO 3 chiral nanoprobe can perform in situ, non-invasive, and precise imaging of pharmacological acute liver injury. In vivo and in vitro experiments have shown that the D/L-Ce@MoO 3 probe had chiral properties, the CD signal decreased upon reaction with H 2 O 2 , and the absorption and PA signals increased with increasing H 2 O 2 concentration. This is because of the catalytic reaction between Ce ions doped in the nanoenzyme and the high expression of H 2 O 2 caused by drug-induced liver injury to produce ·OH, which has a strong oxidizing property to kill tumor cells and destroy the Mo-S bond in the probe, thus converting the chiral probe into an achiral polyoxometalate (POM) with PA signal.
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