The electrochemical N₂ reduction reaction (NRR) represents a green and sustainable route for NH₃ synthesis under ambient conditions. However, the mechanism of N₂ activation in the electrocatalytic NRR remains unclear. Herein, we found that the high spin state Mn³⁺-Mn³⁺ pairs induced by oxygen vacancy in MnO₂ nanosheets greatly enhance the catalytic activities. The strong electron transfer between d orbital of Mn and orbital of N₂ forces the N₂ to be of radical nature, which activates the hydrogenation process and weakens the N≡N bond. Based on the density functional theory (DFT) calculation results, we precisely designed mesoporous MnO₂ nanosheets with rich oxygen vacancies via using methyltriphenylphosphonium bromide (MPB) to induce more Mn³⁺-Mn³⁺ pairs (Mn^3-3-MnO₂), which can achieve a fairly high ammonia yield of up to 147.2 µg·h⁻¹·mg_cat⁻¹_. at −0.75 V vs. reversible hydrogen electrode (RHE) and a high Faradaic efficiency (FE) of 11%. Furthermore, these mesoporous MnO₂ nanosheets exhibit the superior durability with negligible changes in both NH₃ yield and FE after a consecutive 6-recycle test and the current density electrolyzed over a 24-hour period. Our findings offer an approach to designing highly active transition metal catalysts for electrocatalytic nitrogen reduction.

Selective semi-hydrogenation of phenylacetylene to styrene is a crucial step in the polystyrene industry. Although Pd-based catalysts are widely used in this reaction due to their excellent hydrogenation activity, the selectivity for styrene remains a great challenge. Herein, we designed a mesoporous silica stabilized Pd-Ru@ZIF-8 (MS Pd-Ru@ZIF-8) nanoreactor with novel Pd and Ru single site synergistic catalytical system for semi-hydrogenation of phenylacetylene. The nanoreactor exhibited a superior performance, achieving 98% conversion of phenylacetylene and 96% selectivity to styrene. Turnover frequency (TOF) of nanoreactor was up to as high as 2,188 h⁻¹, which was 25 times and 5 times more than the single metal species catalysts, mesoporous silica stabilized Pd@ZIF-8 nanoreactor (MS Pd@ZIF-8), and mesoporous silica stabilized Ru@ZIF-8 nanoreactor (MS Ru@ZIF-8). This catalytic activity was attributed to the synergistic effect of Pd and Ru single site anchored strongly into the framework of ZIF-8, which reduced the desorption energy of styrene and increased the hydrogenation energy barrier of styrene. Importantly, since the ordered mesoporous silica was introduced into the nanoreactor shell to stabilize ZIF-8, MS Pd-Ru@ZIF-8 showed excellent reusability and stability. After the five cycles, the catalytical activity and selectivity still remained. This work provides insights for a synergistic catalytic system based on single-site active sites for selective hydrogenation reactions.

Carbon-carbon (C-C) coupling reactions represent one of the most powerful tools for the synthesis of complex natural products, bioactive molecules developed as drugs and agrochemicals. In this work, a multifunctional nanoreactor for C-C coupling reaction was successfully fabricated via encapsulating the core-shell Cu@Ni nanocubes into ZIF-8 (Cu@Ni@ZIF-8). In this nanoreactor, Ni shell of the core-shell Cu@Ni nanocubes was the catalytical active center, and Cu core was in situ heating source for the catalyst by absorbing the visible light. Moreover, benefiting from the plasmonic resonance effect between Cu@Ni nanocubes encapsulated in ZIF-8, the absorption range of nanoreactor was widened and the utilization rate of visible light was enhanced. Most importantly, the microporous structure of ZIF-8 provided shape-selective of reactant. This composite was used for the highly shape-selective and stable photocatalysed C-C coupling reaction of boric acid under visible light irradiation. After five cycles, the nanoreactor still remained high catalytical activity. This Cu@Ni@ZIF-8 nanoreactor opens a way for photocatalytic C-C coupling reactions with shape-selectivity.

With the increasingly prominent energy and environmental issues, the supercapacitors, as a highly efficient and clean energy conversion and storage devices, meet the requirements well. However, it is still a challenge to enhance the capacitance and energy density of supercapacitors. A novel and highly conductive dodecaborate/MXene composites have been designed for high performance supercapacitors. The surface charge property of MXene was modified by a simple ultrasonic treatment with ammonium ion, and the dodecaborate ion can be inserted into the inner surface of MXene by electrostatic adsorption. Due to the unique icosahedral cage conjugate structure formed by the B-B bond and the highly delocalized three-dimensional π bond structure of the electrons, the negative charge is delocalied on the whole dodecaborate ion, which reduces the ability to bind to cations. Therefore, the cations can move easily, and the dodecaborate can act as a "lubricant" for ion diffusion between the MXene layers, which significantly improves the ion transfer rate of supercapacitors. The dodecaborate/MXene composites can achieve an extremely high specific capacitance of 366 F·g^-1 at a scan rate of 2 mV·s^-1, which is more than eight times higher than that of MXene (43 F·s^-1) at the same scan rate. Our finding provides a novel route on the fabrication of the high performance supercapacitors.

A highly hierarchically ordered macroporous–mesoporous Ce_0.4Zr_0.6O₂ solid solution with crystalline framework walls was directly and simply prepared using polystyrene (PS) microspheres and a block copolymer as dual templates. The PS microspheres and block copolymer were assembled into colloidal crystals and mesoscopic rod-like micelles as macroporous and mesoporous templates, respectively, by a one-step process. This process offers a facile method to prepare hierarchically ordered porous materials. Compared to commercial ceria, the macroporous–mesoporous Ce_0.4Zr_0.6O₂ material significantly improved the ultraviolet resistance and mechanical performance of a polysulfide polymer. Because the ordered macroporous–mesoporous Ce_0.4Zr_0.6O₂ can disperse uniformly in the polysulfide polymer based on the open macroporous structure for diffusion and mobility and mesoporous structure for high surface areas. Furthermore, these results show that better-performing polysulfide polymers can be achieved by adding hierarchically structured materials.