Supported Ag nanocomposites and bimetallic Ag-based nanocomposites with various morphologies and compositions engineered for representative catalytic applications are reviewed.

Ag-based nanoparticles (NPs) catalysts have recently attracted increasing attention in NaBH₄-assisted nitrophenol reduction, especially in 4-nitrophenol (4-NP) reduction. Moreover, Ag-based NPs catalysts are considered to be very promising for practical applications because of their fascinating advantages, e.g., easy preparation, relatively low cost and less toxicity, high activity and good stability. Basically, the size and shape of Ag NPs are well known as the key factors for achieving highly efficient catalytic reduction of 4-NP. In this review, three highly efficient Ag-based NPs catalysts (supported Ag NPs, anisotropic Ag NPs and bimetallic Ag NPs) are highlighted for the 4-NP reduction, including the catalytic mechanism and reaction rate caused by their adjustments in size and shape. Although high catalytic activity has been demonstrated by several Ag-based NPs catalysts, further improvement in the catalytic performance is still desired. In terms of the most recent progress in Ag-based NPs catalysts for 4-NP reduction, this review provides a comprehensive assessment on the material selection, synthesis and catalytic characterizations of these catalysts. Moreover, this review aims to correlate the catalytic performance of Ag-based NPs catalysts with their size and shape, guiding the development of novel cost-effective and high-performance catalysts.

Due to the urgent demand for more anti-cancer methods, the new applications of metal ions in cancer have attracted increasing attention. Especially the three kinds of the new mode of cell death, including ferroptosis, calcicoptosis, and cuproptosis, are of great concern. Meanwhile, many metal ions have been found to induce cell death through different approaches, such as interfering with osmotic pressure, triggering biocatalysis, activating immune pathways, and generating the prooxidant effect. Therefore, varieties of new strategies based on the above approaches have been studied and applied for anti-cancer applications. Moreover, many contrast agents based on metal ions have gradually become the core components of the bioimaging technologies, such as MRI, CT, and fluorescence imaging, which exhibit guiding significance for cancer diagnosis. Besides, the new nano-theranostic platforms based on metal ions have experimentally shown efficient response to endogenous and exogenous stimuli, which realizes simultaneous cancer therapy and diagnosis through a more controlled nano-system. However, most metal-based agents have still been in the early stages, and controlled clinical trials are necessary to confirm or not the current expectations. This article will focus on these new explorations based on metal ions, hoping to provide some theoretical support for more anti-cancer ideas.