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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.

Growing greenhouse gas CO2 is driving the research on the chemical fixation of CO2. Here, the organic reaction of CO2 with benzyl halogen for chemical CO2 fixation under ambient conditions with irr...

The electrochemical splitting of water into hydrogen and oxygen is considered one of the most promising approaches to generate clean and sustainable energy. However, the low efficiency of the oxygen evolution reaction (OER) acts as a bottleneck in the water splitting process. Herein, interface engineering heterojunctions between ZIF‐67 and layered double hydroxide (LDH) are designed to enhance the catalytic activity of the OER and the stability of Co‐LDH. The interface is built by the oxygen (O) of Co‐LDH and nitrogen (N) of the 2‐methylimidazole ligand in ZIF‐67, which modulates the local electronic structure of the catalytic active site. Density functional theory calculations demonstrate that the interfacial interaction can enhance the strength of the Co—Oout bond in Co‐LDH, which makes it easier to break the H‐Oout bond and results in a lower free energy change in the potential‐determining step at the heterointerface in the OER process. Therefore, the Co‐LDH@ZIF‐67 exhibits superior OER activity with a low overpotential of 187 mV at a current density of 10 mA cm−2 and long‐term electrochemical stability for more than 50 h. This finding provides a design direction for improving the catalytic activity of OER., The interface of Co‐LDH@ZIF‐67 is built by the oxygen of cobalt layered double hydroxide (Co‐LDH) and nitrogen of the ZIF‐67, which can modulate the electronic structure of the catalytical site. The Co‐LDH@ZIF‐67 exhibits superior catalytical activity in oxygen evolution reaction with a low overpotential of 187 mV at a current density of 10 mA cm−2.

In a water electrolysis system, the cathode and anode produce H2 and O2 with HER and OER, respectively. The energy conversion efficiency of the electrolysis systems is about 56–73% in practical application, and the low energy conversion efficiency greatly limits the large-scale application. Hence, the electrocatalytic water splitting has attracted much attention. Recently, a variety of heterogeneous catalysts have emerged, showing high catalytic water splitting performance. Among them, the heterojunction catalysts occupied a very important position in emerging catalysts. In the heterojunction catalysts, electrons can be rearranged on heterostructures interfaces to modify the properties of active sites, and synergy of different active sites is used to promote the reaction kinetics. The heterojunction catalysts often show a better activity of electrolysis water than single-component catalysts. Herein, we mainly summarize the design strategies and synthesis methods of various heterojunction catalysts and the related applications of these heterojunction catalysts in HER and OER, and further discusses the catalytical mechanisms in HER and OER processes respectively. Through the summary of present progress in electrocatalytic water splitting, this review provides a reasonable prospect on heterojunction catalysts in electrocatalytic water splitting.

Catechol (CAT) and hydroquinone (HQ) are two important diphenol isomers with a variety of industrial applications. The hydroxylation of phenol catalyzed by transition metal (TM) substituted ZSM-5 is an environmentally benign route for diphenol production, which is usually governed by intracrystalline diffusion. Therefore, the availability of highly oriented TM-ZSM-5 membranes and their utilization in an interphase membrane reactor can significantly promote the hydroxylation of phenol. The continuous and [h0h]-oriented Fe-ZSM-5 membrane on the porous α-Al 2 O 3 was prepared using a new seeded growth method. Characterization was carried out by using SEM, XRD, UV/Vis, and EPMA techniques, which demonstrated that the [h0h]-oriented membrane consists of Fe substituted ZSM-5 crystal grains with an Si/Fe ratio of approximately 75. Compared with the catalytic performance of different sized Fe-ZSM-5 grains loaded in the traditional slurry reactor, the [h0h]-oriented Fe-ZSM-5 membrane in the interphase membrane reactor showed significantly improved phenol conversion and selectivity for CAT and HQ due to the molecular path control in the zeolite membranes.