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The excessive growth of CO2 brings about the global warming and subsequent climate change, which is an increased public concern issue. Currently, the chemical fixation of CO2 is identified as one of the most effective approaches to reduce and utilize CO2. Thus, it is a great challenge to rationally design and construct high‐efficient catalysts for CO2 conversion and utilization. Here, a unique metal‐free bifunctional COF heterogeneous catalyst was successfully achieved via the post‐modified strategy, which simultaneously bears −COOH as Brønsted acidic center and Br− ion as nucleophilic active site. By virtue of abundant porosity, excellent stability, favorable CO2 adsorption, and dual catalytic sites, this material can efficiently facilitate the coupling reaction of CO2 with epoxide to form cyclic carbonate without co‐catalyst under mild conditions. Moreover, it has excellent reusability, without significant reduction of the catalytic activity after at least five cycles. [ABSTRACT FROM AUTHOR]

The electrochemical nitrogen reduction reaction (NRR) offers an energy‐saving and environmentally friendly approach to produce ammonia under ambient conditions. However, traditional catalysts have extremely poor NRR performances because of their low activity and the competitive hydrogen evolution reaction. The high catalytic activity of nanoporous gold (NPG) and the hydrophobicity and molecular concentrating effect of the zeolitic imidazolate framework‐8 (ZIF‐8) were incorporated in the NPG@ZIF‐8 nanocomposite so that the ZIF‐8 shell could weaken hydrogen evolution and retard reactant diffusion. A highest Faradaic efficiency of 44 % and an excellent rate of ammonia production of (28.7±0.9) μg h−1 cm−2 were achieved, which are superior to traditional gold nanoparticles and NPG. Moreover, the composite catalyst shows high electrochemical stability and selectivity (98 %). The superior NRR performance makes NPG@ZIF‐8 one of the most promising water‐based NRR electrocatalysts for ammonia production. [ABSTRACT FROM AUTHOR]

Reactions in the solid state, especially single-crystal-to-single-crystal (SC–SC) transformations, provide an appealing pathway to obtain target crystalline materials with modified properties via a solvent-free green chemistry approach. This feature article focuses on the progress to date in the context of coordination supramolecular systems (CSSs), especially coordination polymers (CPs) or metal–organic frameworks (MOFs), which show interesting dynamic natures upon exposure to various exogenous stimuli, including concentration, temperature, light and mechanical force, as well as their synergic effect. In essence, dynamic CSSs normally possess crucial crystalline-reactive characteristics: (i) metal ions or clusters with unstable or metastable electronic configurations and coordination geometries; (ii) organic ligands bearing physicochemically active functional groups for subsequent reactions; (iii) polymeric networks of high flexibility for structural bending, rotation, swelling, or shrinking; (iv) guest moieties to be freely exchanged or eliminated by varying the environmental conditions. The significant changes in catalytic, sorption, magnetic, or luminescent properties accompanied by the structural transformations will also be discussed, which reveal the proof-of-concept thereof in designing new functional crystalline materials. [ABSTRACT FROM AUTHOR]

The lack of highly efficient and stable electrocatalysts for anodic hydrogen oxidation reaction (HOR) has limited the large-scale industrial application of alkaline exchange membrane fuel cell. In this work, a Pt-free Ru/CeO 2 heterostructure electrocatalyst with outstanding catalytic activity and stability for alkaline HOR is developed. The synthesized Ru/CeO 2 with synergistic heterogeneous interface exhibits a high kinetic current density reaching 21.7 mA cm−2 at an overportentail of 50 mV, which is nearly 11-fold higher than that of the contrastive Ru/C catalyst and almost the same as that of commercial Pt/C catalyst. Importantly, this electrocatalyst also shows high CO resistance that Pt/C catalyst lacks. Electrochemical results and spectral studies show that CeO 2 not only efficiently adjusts the electronic microenvironment of Ru site to promote H ad adsorption, but also provides the adsorption sites for OH ad at a low potential. As a result, the introduced CeO 2 synergistically promotes hydrogen oxidation, H 2 O formation and CO removing, thereby enhancing the HOR performance of Ru nanoclusters. • A new-style CeO 2 nanorods supported Ru nanoclusters heterostructure catalyst was synthesized. • The strong metal-support interaction in Ru/CeO 2 effectively promotes H ad adsorption. • The CeO 2 nanorod supports with oxygen vacancies provides abundant active sites for OH ad adsorption. • The Ru/CeO 2 exhibits high activity and CO tolerance for alkaline hydrogen oxidation. [ABSTRACT FROM AUTHOR]

This work presents a unique electrocatalyst of nanoporous AuPd alloy electrocatalyst. By utilizing the abundant active sites from porous structure and the synergia between Au and Pd, we achieve superior ENRR enhancement with high ammonia yield of 43.6 μg·h−1·cm−2 and Faradaic efficiency of 43.8%. [Display omitted] • Unique porous AuPd alloy nanostructures (pAuPdNs) have been prepared with Pd homogeneously distributed throughout the entire nanostructure and Au concentrated in the core. • The designed pAuPdNs structure achieves high ammonia production of 43.6 μg·h−1·cm−2 and superior catalytic efficiency of 43.8 %. • PAuPdNs structure shows excellent selectivity (95%), as well as long-time and multi-cyclic stability, which prove the suitably promising application for ammonia production. In industry, production of ammonia mainly relies on the intensive Haber-Bosch process, but it consumes high energy with low efficiency and generates a large number of green-house gases. Electrocatalytic nitrogen reduction reaction (ENRR), as an alternative method for fixing N 2 under ambient conditions, provides a feasible strategy for sustainable development of N 2 cycle storage and utilization of renewable energy. However, traditional nanocatalysts exhibit extremely poor ENRR performance due to low activity of the solid structure and intense hydrogen evolution reactions of single component. Herein, we design and prepare porous gold–palladium nanoalloys (pAuPdNs), which effectively enhance ENRR by the excellent catalytic activity of Au and the significant N 2 fixation ability of Pd, as well as the nanoporous structure and synergistic effect between alloy components. The electrochemical results show the NH 3 yield of the catalyst is as high as 43.6 μg·h−1·cm−2, and Faradaic efficiency reaches 43.8%, which are superior to the performances of most reported water-based ENRR electrocatalysts. Besides, the selectivity of 95% and stability also exhibit enhancement than numerous reported researches. As compared with solid alloy and porous Au or Pd structures, the superiority of pAuPdNs states the influence of alloying and porous structure. Hence pAuPdNs are proved to be the efficient, stable, and promising electrocatalysts for N 2 reduction reaction at ambient temperature and atmospheric pressure. [ABSTRACT FROM AUTHOR]

A new-style superhydrophilic self-supported Y-doping Ni 2 P electrode with excellent electrocatalytic activity for alkaline HER is developed. The doped Y atoms promote the water dissociation kinetics (Volmer step), thereby enhancing its catalytic activity for alkaline HER. Its superhydrophilic self-supported electrode further improves the catalytic efficiency and stability at high current density. [Display omitted] • A new-style superhydrophilic self-supported Y-Ni 2 P@GP electrode is prepared. • The doped Y atoms observably promote the water dissociation kinetics of Y-Ni 2 P@GP for alkaline hydrogen evolution. • The superhydrophilic self-supported electrode further improves the catalytic activity and stability at high current density. • The Y-Ni 2 P@GP electrode exhibits excellent activity and stability for alkaline hydrogen evolution. The development of efficient and stable alkaline hydrogen evolution catalyst under high current density is essential for the large-scale application of alkaline water electrolysis technology. Here, we prepare a superhydrophilic self-supported Y-doping Ni 2 P electrode (Y-Ni 2 P@GP) by an electrodeposition method following high-temperature phosphorization, which exhibits an excellent alkaline hydrogen evolution reaction (HER) activity at high current density. At 500 mA cm−2, the Y-Ni 2 P@GP electrode requires a much lower overpotential (160 mV) than the Pt/C(20 %)@GP and pure Ni 2 P@GP electrodes, and stably operates for 300 h with negligible degradation. The enhanced catalytic performance of the Y-Ni 2 P@GP electrode is attributed to that the doped oxyphilic Y atom as robust water-dissociation site prominently accelerates the sluggish Volmer step of alkaline HER, which collaborates with highly efficient Ni hydrogen adsorption site to boost the overall HER kinetics. Furthermore, its superhydrophilic electrode surface facilitates H 2 bubble detachment with small and uniform sizes, and its self-supported electrode structure with strong catalyst adhesion ensures the rapid transfer of electrons and prevents the fall off of catalyst. This further improves the catalytic efficiency and stability under high current density. [ABSTRACT FROM AUTHOR]