Graphical Divalent nickel can be decorated onto CdS/CdSe core/shell quantum dots (QDs) in a controlled fashion. Under optimized conditions these QDs catalyze light-induced H 2 evolution from water with a turnover frequency of 322 h −1 with respect to Ni and a quantum yield of 12.3 % at 520 nm. The search for a low-cost, noble-metal-free cocatalyst to replace expensive Pt for hydrogen (H 2 ) photogeneration in water has become a hot research topic, and among these, Ni-based cocatalysts are promising and highly desired. Developing new strategies and protocols to obtain Ni-based cocatalysts with high activity is therefore vitally important. Herein, we develop a new method to efficiently decorate divalent Ni onto pre-synthesized CdS/CdSe core/shell quantum dots (QDs). The concentration of Ni on the QDs can be easily tuned by varying the amount of the Ni precursor introduced during the synthesis. Further analyses reveal that Ni 2+ can be strongly decorated onto QDs. Impressively, the Ni-decorated QDs displayed a significantly enhanced H 2 photogeneration performance as compared to the two components prepared separately. Through the optimization of the Ni concentration on the QDs, the turnover frequency (TOF) with respect to Ni and quantum yield ( ) at 520 nm for H 2 evolution from water could reach 322 h −1 and 12.3 %, respectively. A possible mechanism has also been proposed and discussed in detail.
Yanbin Zhang,Shuowen Guo,Xiaolong Wang,Ying Li,Tong Xu,Yinghui Sun,Jie Bai
Non-noble metal-based catalysts used for dry reforming of methane (DRM) undergo extensive deactivation, mainly because of the carbon deposition. Herein, the conventional NiCo-CNFs catalyst was modified by minor Mo promoter for facilitating CO and H 2 produced from DRM. This not only improves the catalytic stability of the catalyst, with CH 4 conversion up to 97.7 % after 720 min at 850 ℃, but also reduces the generation of carbon deposition. The addition of an appropriate amount of Mo enhanced the metal-support interaction, and formed Mo 2 C in the reaction. The generation of Mo 2 C also provided more active sites for DRM reaction, which is also benefited to NiCoMo 0.1 -CNFs catalyst exhibited optimal activity and stability. The reaction pathway of NiCoMo 0.1 -CNFs catalyst in DRM reaction was elucidated through in-situ DRIFTS, and the activation mechanism of the catalyst for CH 4 and CO 2 was revealed. This study revealed the key role of Mo 2 C, providing a feasible solution for inhibiting carbon deposition and improving the catalytic stability of DRM reactions.
The versatility of lanthanide-doped near-infrared (NIR, 700–1,700 nm) luminescent nanoparticles makes them valuable tools in various scientific and technological fields, from bioimaging to information security. However, the luminescence intensity of typical lanthanide-doped nanoparticles is significantly influenced by the efficiency of the sensitizer. The introduction of transition metal ions (such as Cr 3+ , Mn 2+ and Ni 2+ ) can greatly enrich the library of lanthanide NIR luminescence nanoparticles. We have reported a new crystalline nanoparticle, Na 3 CrF 6 , for high-brightness NIR emission from lanthanide activators (such as Er 3+ , Tm 3+ , Yb 3+ or Nd 3+ ). As an emerging luminescent material, a straightforward and scalable synthesis approach for these nanostructures holds promise for their broader application. Here we have refined and standardized the steps for transition metal-sensitized lanthanide luminescent nanoparticles, thereby establishing a library of advanced luminescent materials for researchers engaged in luminescent materials. The Protocol enables the precise preparation of chromium-, manganese- and nickel-trifluoroacetate, the synthesis of three types of transition metal-sensitized lanthanide nanoparticle and the fabrication of chromium-sensitized lanthanide homogeneous and heterogeneous nanostructure. Moreover, we provide verification protocols for each step’s output and guidelines for adjusting synthesis conditions. To aid in the reproducible synthesis of these nanoparticles, we also include a troubleshooting guide of the various stages. The estimated duration for synthesizing transition metal trifluoroacetate, transition metal-sensitized lanthanide nanoparticles and core–shell transition metal-sensitized lanthanide nanoparticles are ~70, 30 and 30 h, respectively. These procedures can be carried out by users with expertise in chemistry or materials science.
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