To overcome the disadvantages of Cu-based catalysts, such as the low dispersion of active components and insufficient active species, several 15% Cu-L x /AC catalysts for acetylene hydrochlorination were synthesized based on strong interactions between a ligand and CuCl2 precursors. The introduction of the methyldiphenyloxophosphine (MDPO) ligand effectively modulated the electronic properties of the metal centers, which contributed to the construction of a highly dispersed Cu–P/Cl local structure with Cu1+/Cu2+ as a plausible active center. The sintering of active components in the catalyst may be one of the main reasons for the decrease in catalytic performance. Meanwhile, the enhanced adsorption and activation of the catalyst for C2H2 and HCl molecules resulted in improved coking resistance. The most active catalyst (15% Cu8MDPO1/AC) could achieve a stable acetylene conversion of 97% at 180 °C, a gas hourly space velocity (GHSV) (C2H2) of 180 h–1, and a feed volume ratio (V HCl/V C2H2 ) of 1.15, outperforming the benchmark catalyst. The excellent activity and stability in a 300 h laboratory test at a high GHSV and a 3414 h industrial sideline test at an industrial GHSV render the 15% Cu8MDPO1/AC catalyst as a reference for the construction of other catalysts from an environmental, economic, and application prospect perspective.

Owing to the low dispersion and deficiency of active species in Pt catalysts, Pt-complexes catalysts (Pt–L x /SAC–IPA) were synthesized using 2-propanol (IPA) solvent via ligand coordination strategy. The IPA, which exhibits a low boiling point and weak polarity, promotes the dispersion of Pt species. Further, the introduction of phthalimide ligand (L1) modulates the electronic properties of active metals, thereby constructing the single-site-dispersed Cl–Pt–N local structure bearing Pt­(II) (presumably the active center of the reaction). Concurrently, the enhanced adsorption and activation performances of the catalyst toward an HCl reactant, as well as its weakened performances toward a C2H2 reactant, improve its anticoking performance and lower the reaction energy barrier. Therefore, the most active Pt–L1/SAC–IPA catalyst achieves an outstanding performance comparable with that of the standard Au/activated carbon (AC)–aqua regia (AR) catalyst, and it is reasonable to conclude that the L1 ligand functioned as a critical “key” in the Pt-based catalytic acetylene hydrochlorination.

The development of non‐noble metal catalysts is crucial for hydrogen production. In this study, electrochemically reconfigurable Fe2O3@NiO‐x composite catalysts were synthesized within tens of seconds using a simple microwave deposition method. Interestingly, Fe2O3@NiO‐5 exhibited a high‐speed and deep surface reconstruction capability, greatly enhancing the hydrogen evolution reaction (HER) activity. DFT calculations also confirmed that the reconstruction process optimized the adsorption energy of H2O and H intermediate to promote HER kinetics. The optimized Fe2O3@NiO‐5 electrode only afforded an overpotential of 295 mV at 10 mA cm−2 and it steadily functioned for 25 h for HER in 1 M KOH. In addition, benefiting from the combination of Fe2O3 and NiO layer during the synthesis process, Fe2O3 and NiO converted into FeOOH and NiOOH, respectively, resulted in the excellent oxygen evolution reaction (OER) activity of Fe2O3@NiO‐5. The as‐prepared Fe2O3@NiO‐5 only required an overpotential of 186 mV at 10 mA cm−2 and exhibited excellent stability for up to 144 h. As a bifunctional catalyst, the Fe2O3@NiO‐5 electrode can deliver a current density of 20 mA cm−2 at a low voltage of 1.78 V with high durability for water splitting. This work can provide a new perspective for constructing advanced non‐noble metal electrode.

BackgroundCu(II) is considered to be a heavy metal ion that is quite hazardous to water.AimsZinc oxide‐montmorillonite composite (ZnO‐Mt) for the removal of Cu(II) from aqueous solutions.Materials & MethodsZnO‐Mt was prepared through ion exchange followed by heat treatment to form a highly effective adsorbent.ResultsThe structure and morphology of the composite were investigated by X‐ray diffraction, scanning electron microscope, and fourier transform infrared spectroscopy and it was found that Zinc oxide was successfully coated on montmorillonite. The composite has a superior removal effect on Cu(II) in an aqueous solution with an adsorption capacity of 192.89 mg·g−1. The adsorption kinetic model and the adsorption isotherm model are described by the pseudo‐second‐order kinetic equation and the Langmuir equation, respectively. The activation energy (Ea) was 84.18 kJ·mol−1, indicating that the adsorption was dominated by chemisorption. In addition, ZnO‐Mt can be applied in a wide pH range (3 ~ 8) and exhibits satisfactory selectivity for the adsorption of Cu(II) in the presence of coexisting cations. The removal efficiency of ZnO‐Mt for Cu(II) remains at 72% of the fresh adsorbent after five cycles.DiscussionA combination of experiment, characterization, and density functional theory analysis showed that the mechanism of Cu(II) removal was mainly surface complexation, ion exchange, and electrostatic attraction.ConclusionTherefore, the ZnO‐Mt composite is a promising and efficient adsorbent for the removal of Cu(II) from aqueous solutions.

The experimental and theoretical studies on the adsorption of Cu(II) on the surface of Na-montmorillonite (Na-Mt) were reported. Effects of batch adsorption experimental parameters were studied. Density functional theory (DFT) and molecular dynamics (MD) simulations were used to study the adsorption of Cu(II) on montmorillonite(001) surface. The adsorption reached equilibrium within 80 min and the adsorption capacity was 35.230 mg · g–1 at 25 °C. The adsorption data of Cu(II) were consistent with pseudo-second-order kinetic and Langmuir isotherm models. The activation energy (Ea) was 37.08 kJ · mol–1, which implied the nature of physical adsorption. The thermodynamic experiment illustrated that the adsorption was a spontaneous endothermic behavior. The influence of coexisting cations on the adsorption capacity of Cu(II) was Mg(II) > Co(II) > Ca(II) > Na(I). The simulation results demonstrated that there were no significant differences in the adsorption energy of Cu(II) at the four adsorption sites on the montmorillonite(001) surface. Cu(II) had more electron transfer than Na(I). The diffusion coefficient of Cu(II) in the aqueous solution system containing montmorillonite was 0.850 × 10–10 m2 · s–1. A considerable amount of Cu(II) ions were adsorbed at a distance of 0.257 and 2.25 Å from the montmorillonite(001) surface. The simulation results provided strong supporting evidence for experimental conclusions.