The construction of biomimetic cluster catalysts with metalloenzyme-like active sites may open an avenue for the challenging transformation of greenhouse gases (e.g., CO 2 ) to high-value chemicals. Cu-enzymes occur in all three biological kingdoms, with Cu Z clusters serving as representative reaction sites that catalyze challenging transformations. However, artificial Cu clusters with analogous Cu Z structures and high stability are still rare. In this work, we have successfully adopted a Ti 9 -oxo nanoring as an inorganic templating scaffold to isolate a small Cu 4 cluster, which can be regarded as a atomically precise bioinspired cluster with metalloenzyme-like catalytic sites (Cu Z ). Importantly, Cu 4 @Ti 9 displays high selectivity for the electrocatalytic reduction of CO 2 to C 2 H 4 (FE: 47.6 ± 3.4%) at 400 mA cm −2 and good catalytic durability (8 h). The bioinspired Cu 4 @Ti 9 not only represents the first example of Cu cluster directly encapsulated by a metal-oxo shell but also opens the CO 2 electroreduction to ethylene applications of atomically precise metallic clusters.
Nanosizedceria (n-CeO2) was synthesized by a facile method in 2-methylimidazolesolution. The characterization results of XRD, N2 adsorption-desorption, Raman and TEM indicate that n-CeO2 shows a regular size of 10 ± 1 nm, a high surface area of 130 m2·g−1 and oxygen vacancies on the surface. A series of CuO/n-CeO2 catalysts (CuCeOX) with different copper loading were prepared for the preferential oxidation of CO in H2-rich gases (CO-PROX). All CuCeOX catalysts exhibit a high catalytic activity due to the excellent structural properties of n-CeO2, over which the 100% conversion of CO is obtained at 120 °C. The catalytic activity of CuCeOX catalysts increases in the order of CuCeO12 < CuCeO3 < CuCeO6 < CuCeO9. It is in good agreement with the order of the amount of active Cu+ species, Ce3+ species and oxygen vacancies on these catalysts, suggesting that the strength of interaction between highly dispersed CuO species and n-CeO2 is the decisive factor for the activity. The stronger interaction results in the formation of more readily reducible copper species on CuCeO9, which shows the highest activity with high stability and the broadest temperature “window” for complete CO conversion (120–180 °C).
ZnO is an important sensitive semiconductor gas material, it belongs to surface-controlled gas sensors, which has been developed as early as in the 60s. Compare to another two series of metal oxide gas sensing materials SnO2 and Fe2O3, ZnO is more stable. But its sensitivity is lower and its working temperature is higher, moreover, its selectivity isn’t good[1]. Therefore, the improvement of ZnO gas sensitive materials mainly focuses on raising sensitivity, improving selectivity, lowering temperature and other aspects of the work.ZnO films have a certain potential market and good industrical prospect. With the rapid deep development of the research, the application of ZnO thin film technology will continue to permeate into many kinds of areas.Including production and life. At present,these methods that have been reported such as precious metals, rare earth doped oxide composite doped, surface modification have achieved good progress[2~5].
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