An ultra-low loading (0.08 wt.%) cobalt single-atom catalyst, synthesized by the adsorption of trace amounts of cobalt salt onto a zeolitic imidazolate framework-8 (ZIF-8) precursor, followed by pyrolysis under Ar at 800 °C, exhibits exceptional performance in the catalytic transfer hydrogenation of furfural to furfuryl alcohol. Under optimized conditions (120 °C, 6 h), the catalyst achieved complete furfural conversion and a selectivity of 96.5% toward furfuryl alcohol. Remarkably, its turnover frequency (TOF) reached 1290.6 h⁻¹, which is three to four orders of magnitude higher than that of previously reported single Co catalysts. The superior catalytic activity is attributed to the uniformly dispersed Co-N₄ matrix and abundant weak and moderate acid sites. Furthermore, Co-ZIF-8-800 exhibited broad substrate scope via the Meerwein–Ponndorf–Verley (MPV) mechanism. This work provides a promising strategy for designing low-cost and highly efficient non-noble metal catalysts for the conversion of biomass-derived platform molecules.

Hydrodeoxygenation (HDO) is vital important for the valorization of oxygen-rich biomass derivatives into high-energy-density fuels and valuable chemicals by selective removal of oxygen-containing functional groups. Low-cost NiFe-based bimetallic catalysts, which integrated the excellent hydrogen activation ability of Ni with the selective adsorption and cleavage of oxygen-containing functional groups of Fe, were attractive in HDO of biomass. However, the limited insights into the coordination structures of active sites and the effects of heteroatom-doping hindered the in-depth understanding of structure−activity relationship in HDO. Herein, a highly selective Ni-280/Fe-N-C-800 catalyst was fabricated via two-step pyrolysis, which afforded 96.3% 2,5-dimethylfuran (DMF) selectivity and complete 5-hydroxymethylfurfural (HMF) conversion at 240 °C and 4 MPa H₂, comparable to state-of-the-art catalysts. More importantly, comprehensive characterizations and fruitful experimental results combined with DFT calculations confirmed that the Fe-N₄-assisted NiFe alloy nanoparticles (NPs) served as the core active sites, then promoting by metal (M)-N_x coordination structures. This work not only elucidated the structure−activity relationship between NiFe alloy catalysts and reactants, but also provided theoretical guidance for selectivity control in HDO process.

The photocatalytic co-reduction of CO₂ and NO₃⁻ is a sustainable method for urea synthesis under mild condition. However, the low photocatalytic yield of urea is a challenge, due to the sluggish kinetics of the C–N coupling reaction. Herein, we successfully designed a TiO₂ nanoparticle modified Cu nanorod photocatalyst (TiO₂@Cu) for simultaneously promoting the NO₃⁻ reduction and CO₂ reduction reaction in the photocatalytic synthesis of urea. The TiO₂ nanoparticles were uniformly covered onto the surface of the Cu nanorod via a simple one-pot strategy, and the as-prepared well-integrated core–shell TiO₂@Cu showed excellent activity in photocatalytic urea synthesis, reaching up to 72.8 μmol·g⁻¹·h⁻¹ of urea yield. The turnover frequency of TiO₂@Cu is 30.1 times higher than that of pure TiO₂. Furthermore, the photocatalytic performance of TiO₂@Cu remains stable after 10 cycles, with no significant decline in urea yield. The remarkable photoactivity is attributed to the unique Ti–O–Cu bond in heterojunction interface of TiO₂@Cu, and Ti–O–Cu bond provides a favorable electron transfer pathway from TiO₂ to Cu, which accelerates the transfer of photogenerated charge and reduces the recombination of hole and electron. Meanwhile, the introduction of Cu alters the energy band structure of TiO₂, resulting in a smaller band gap and further improving the utilization of light. The energy barrier of the C–N coupling reaction in Ti–O–Cu site (−3.22 eV) is much lower than that of individual Cu site (1.21 eV). This work provides important inspiration and guiding significance towards highly efficient photocatalytic synthesis of urea.

Ammonia plays an irreplaceable role in agricultural production and also is an important chemical raw material and energy carrier. Developing a catalyst for the electrochemical NO₃⁻ reduction reaction (NO₃RR) to synthesize ammonia is crucial for energy, food security and pollution control. Herein, by adjusting the Cu/Ni ratio, we report a simple impregnation and calcination method to synthesize a N-doped bamboo-like carbon nanotube (CNT)-encapsulated CuNi alloy catalyst (Cu₇Ni₃-CNT). Cu₇Ni₃-CNT reveals an excellent ammonia synthesis performance, which has the highest Faraday efficiency (FE, 99.18%) at −0.8 V vs. reversible hydrogen electrode (RHE), along with an ammonia production rate of 20.90 mg·cm⁻²·h⁻¹. In addition, the highest ammonia production rate of Cu₇Ni₃-CNT can reach 23.21 mg·cm⁻²·h⁻¹, with a high FE (90.80%) at −1.0 V vs. RHE. At the same time, the electrocatalyst displays exceptional stability, which can operate steadily for 400 h at 300 mA·cm⁻². The high catalytic activity and excellent stability derive from catalyst structure and the synergistic effect between Cu₇Ni₃ alloy and encapsulating bamboo-like CNT. The incorporation of Ni enhances the intrinsic activity of Cu for NO₃RR. CNT endows the catalyst with a larger specific surface area, more exposed active sites to further improve the apparent activity, and higher stability. The internal cavity of CNT also contributes to the enrichment of nitrate. Furthermore, in-situ Raman spectroscopy and density functional theory (DFT) calculations reveal that Cu in the alloy can effectively adjust the adsorption energy of *NO₃ by Ni element and increase the activity of *H as the reduction driving force, thereby improving the intrinsic activity of NO₃RR.

In response to alleviate the escalating environmental pollution and energy scarcity, the development of a cost-effective, efficient and stable bifunctional oxygen reduction reaction/oxygen evolution reaction (ORR/OER) electrochemical catalyst for new energy conversion devices holds significant value. In this context, we present a two-step hydrothermal/annealing synthesis approach of CoFe alloy nanoparticles on nitrogen-doped ultra-thin carbon nanosheets as an excellent ORR/OER bifunctional catalyst. The hydrothermal process facilitates the intercalation of CoFe layered double hydroxide (CoFe LDH) onto the nitrogen-doped ultra-thin carbon layer, followed by an in-situ transformation into carbon-coated nano-alloy particles (Co₃Fe₇@NCNS) during high-temperature annealing. Co₃Fe₇@NCNS exhibits exceptional ORR activity (onset potential (E_onset) = 0.962 V, half-wave potential (E_1/2) = 0.869 V) and bifunctional electrocatalytic performance, accompanied by a low reversible overvoltage of 0.82 V. Combining X-ray absorption fine structure (XAFS) spectroscopy and density functional theory (DFT) calculations, we elucidate that the strong interactions between the synthesized Co₃Fe₇@NCNS alloy particles optimize the adsorption energy of oxygen intermediates, thereby playing a crucial role in enhancing catalytic activity. Furthermore, the Co₃Fe₇@NCNS-equipped Zn-air battery demonstrates a higher open-circuit voltage of 1.46 V and remarkable power density of 202.8 mW·cm⁻². It also exhibits excellent cycling stability, with a high specific capacity of 779.2 mA·h·g⁻¹, outperforming that of the Pt/C-RuO₂ counterpart.

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.