Quantum optimal control, a toolbox for devising and implementing the shapes of external fields that accomplish given tasks in the operation of a quantum device in the best way possible, has evolved into one of the cornerstones for enabling quantum technologies. The last few years have seen a rapid evolution and expansion of the field. We review here recent progress in our understanding of the controllability of open quantum systems and in the development and application of quantum control techniques to quantum technologies. We also address key challenges and sketch a roadmap for future developments. 

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Quantum optimal control in quantum technologies. Strategic report on current status, visions and goals for research in Europe

Layered double-hydroxide (LDH) has been considered an important class of electrocatalysts for the oxygen evolution reaction (OER), but the adsorption-desorption behaviors of oxygen intermediates on its surface still remain unsatisfactory. Apart from transition-metal doping to solve this electrocatalytic problem of LDH, rare-earth (RE) species have sprung up as emerging dopants owing to their unique 4f valence-electronic configurations. Herein, the Er is chosen as a RE model to improve OER activity of LDH via constructing nickel foam supported Er-doped NiFe-LDH catalyst (Er-NiFe-LDH@NF). The optimal Er-NiFe-LDH@NF exhibits a low overpotential (191 mV at 10 mA cm-2 ), high turnover frequency (0.588 s-1 ), and low activation energy (36.03 kJ mol-1 ), which are superior to Er-free sample. Electrochemical in situ Raman spectra reveal the facilitated transition of Ni-OH into Ni-OOH for promoted OER kinetics through the Er doping effect. Theoretical calculations demonstrate that the introduction of Er facilitates the spin crossover of valence electrons by optimizing the d band center of NiFe-LDH, which leads to the GO -GHO closer to the optimal activity of the kinetic OER volcano by balancing the bonding strength of *O and *OH. Moreover, the Er-NiFe-LDH@NF presents high practicability in electrochemical water-splitting devices with a low driving potential of and a well-extended driving period.

Improving the Oxygen Evolution Activity of Layered Double-Hydroxide via Erbium-Induced Electronic Engineering.

Significance The combined radical and nonradical reactions induced by peroxymonosulfate (PMS) activation can promise deep mineralization and selective removal of micropollutants from complex wastewater. However, nonhomogeneous metal-based catalysts with single active sites lead to a low efficiency of electron cycling for both radical and nonradical generation. In this study, asymmetric Co–O–Bi sites were constructed to achieve rapid electron cycling while achieving site synergy, thus effectively activating PMS to generate radicals and nonradicals. The presence of asymmetric sites can tune and optimize the catalytic performance through structural modulation, which can effectively remove and mineralize micropollutants from organic and inorganic compounds under the environmental background.

Generating dual-active species by triple-atom sites through peroxymonosulfate activation for treating micropollutants in complex water

This work provides a novel rare-earth-based catalyst of N-regulated lanthanum phosphate (N-LaPO4/C) and the corresponding rational measurement of catalytic activity for the oxygen reduction reaction (ORR). Developed N-LaPO4/C displays more positive half-wave potential (0.88 V) and onset potential (1.02 V) for the ORR, surpassing commercial Pt/C (0.96 and 0.85 V) and most reported research works. The robust stability of N-LaPO4/C for the ORR is also demonstrated. Comprehensive analyses through X-ray absorption spectroscopy, surface Pourbaix diagram, microkinetic modeling, and data mining based on an advanced explainable machine learning demonstrate a self-oxidation process on LaPO4 during the alkaline ORR and identify the key role of N in LaPO4 in promoting ORR. N-doped LaPO4 in N-LaPO4/C is found to be an active center. Further findings show that N-LaPO4/C + RuO2 can be applied in rechargeable Zn-air batteries as an air cathode, showing a good power density and a long cycle life. 

N-doped LaPO4: An effective Pt-free catalyst for electrocatalytic oxygen reduction

In this work, the activation effect of vacuum thermal treatment on MIL-101(Fe) (MIL: Materials of Institute Lavoisier) was investigated for the first time. It demonstrated that vacuum thermal activation could accelerate the activation of persulfate (PS) by MIL-101(Fe), and the enhancement of the catalytic capacity of MIL-101(Fe) was mainly attributed to the change in the FeII/FeIII mixed-valence center. The results of the SEM and XRD showed that vacuum thermal activation had a negligible effect on the crystal structure and particle morphology of MIL-101(Fe). Meanwhile, the higher temperature of vacuum thermal activation caused a higher relative content ratio of FeII/FeIII. A widely used azo dye, X-3B, was chosen as the probe molecule to investigate the catalytic performance of all samples. The results showed that the activated samples could remove X-3B more effectively, and the sample activated at 150 °C without regeneration could effectively activate PS to remove X-3B for at least 5 runs and approximately 900 min. This work highlights the often-overlooked activation effect of vacuum thermal treatment and provides a simple way to improve the catalytic capacity and reusability of MIL-101(Fe) which is beneficial for the application of MIL-101(Fe)/PS systems in azo dye wastewater treatment.

https://www.mdpi.com/2073-4344/9/11/906/pdf

Acceleration of Persulfate Activation by MIL-101(Fe) with Vacuum Thermal Activation: Effect of FeII/FeIII Mixed-Valence Center

Developing non-noble catalysts with superior activity and durability for oxygen evolution reaction (OER) in acidic media is paramount for hydrogen production from water. Still, challenges remain due to the inadequate activity and stability of the OER catalyst. Here, we report a cost-effective and stable manganese oxybromide (Mn7.5O10Br3) catalyst exhibiting an excellent OER activity in acidic electrolytes, with an overpotential of as low as 295 ± 5 mV at a current density of 10 mA cm-2. Mn7.5O10Br3 maintains good stability under operating conditions for at least 500 h. In situ Raman spectroscopy, X ray absorption near edge spectroscopy, and density functional theory calculations confirm that a self-oxidized surface with enhanced electronic transmission capacity forms on Mn7.5O10Br3 and is responsible for both the high catalytic activity and long-term stability during catalysis. The development of Mn7.5O10Br3 as an OER catalyst provides crucial insights into the design of non-noble metal electrocatalysts for water oxidation. 

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Efficient and stable noble-metal-free catalyst for acidic water oxidation

Employing in situ-generated metal complexes as structural decorating agents, we, for the first time, isolated two [Co(bipy)3]3+-templated silver halobismuthate hybrids, namely [Co(bipy)3]2Ag4Bi2X16 (X = Br (1), I (2); bipy = 2,2'-bipyridine). Compounds 1 and 2 belong to the isomorphic phrases and exhibit the nonperovskite structures characteristic of the discrete [Ag4Bi2X16]6- anions. UV-vis absorption spectra analyses showed that the optical band gaps of compounds 1 and 2 are 2.40 and 1.95 eV, respectively, implying the visible light responding semiconductor properties. Moreover, under the alternate light illumination, the title compounds exhibited "on/off" photocurrent behaviors, with high photocurrent densities comparable to many metal halide hybrids. Presented in this work also involved the Hirshfeld surface analyses and X-ray photoelectron spectroscopy studies together with the theoretical band structures, density of states, and electron wave functions.

Two [Co(bipy)3]3+-Templated Silver Halobismuthate Hybrids: Syntheses, Structures, Photocurrent Responses, and Theoretical Studies.

[NH4][Fe(bipy)3]2[Ag6Br11]: Synthesis, structure, characterization and photocurrent response

Two heterometallic silver-iodoplumbates with [Fe(phen)3]2+ complexes: Syntheses, structures, photocurrent responses and theoretical studies

An organic-inorganic hybrid silver iodobismuthate characteristic of the infrequent [Ag2BiI6L2] cluster (L = I or I3) and with a unique Ag/Bi molar ratio (2/1), namely, [Zn(bipy)3]2Ag2BiI6(I)1.355(I3)1.645 (bipy = 2,2'-bipyridine; 1), was solvothermally synthesized, and structurally, optically, and theoretically studied. Intriguingly, compound 1 exhibited semiconductor behavior with an optical band gap of 2.33 eV, which endowed it with excellent photoelectric and photocatalytic properties. Electronic structure calculations further revealed that the relative separate conduction band (CB) and valence band (VB) in compound 1 may be responsible for the good optical activity. This study also includes the Hirshfeld surface analyses, thermogravimetric measurements and X-ray photoelectron spectroscopy (XPS) characterization.

Jun Jun Li

Papers

Efficient and stable noble-metal-free catalyst for acidic water oxidation

Two [Co(bipy)3]3+-Templated Silver Halobismuthate Hybrids: Syntheses, Structures, Photocurrent Responses, and Theoretical Studies.

[NH4][Fe(bipy)3]2[Ag6Br11]: Synthesis, structure, characterization and photocurrent response

Two heterometallic silver-iodoplumbates with [Fe(phen)3]2+ complexes: Syntheses, structures, photocurrent responses and theoretical studies

A new metal complex-templated silver iodobismuthate exhibiting photocurrent response and photocatalytic property.