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2025 Volume 41 Issue 12
2025, 41(12):
Abstract:
2025, 41(12): 100152
doi: 10.1016/j.actphy.2025.100152
Abstract:
Two-dimensional covalent organic frameworks (COFs) are considered among the most potential crystalline porous materials for solar-driven hydrogen production. However, it is usually necessary to introduce noble metal cocatalysts to boost the hydrogen evolution capacity of COFs. In this work, a unique S-scheme heterojunction structured TtTfp-COF/NiS composite material was effectively developed by growing metal sulfide on the typical two-dimensional covalent organic framework TtTfp-COF through a simple solvothermal synthesis method. In this structure, linear structure of rod-like NiS is more stable and convenient for further surface modification. It also provides key active sites and promotes efficient electron transfer, significantly enhancing the hydrogen evolution efficiency. The covalent organic framework enhances charge carrier transport efficiency by controlling the spatial organization of precursors and ligands. It is indicated by the experimental findings that a hydrogen evolution rate of 5978 μmol·g−1·h−1 can be achieved for the NT-20 sample, which about 11.5 times higher than that of the initial TtTfp-COF (520 μmol·g−1·h−1). In addition, the material exhibits a notable quantum efficiency of 1.96% when exposed to 420 nm illumination. Both experimental results and theoretical analyses have been confirmed to improve the hydrogen evolution rate via photocatalysis and the charge transfer mechanism within the S-scheme heterojunction has been thoroughly elucidated. The design and development of non-precious metal COF-based photocatalysts are provided with new insights in this article, and new ideas for the construction of S-scheme heterojunctions are offered by the synergistic combination of inorganic and organic materials in photocatalysis.![]()
Two-dimensional covalent organic frameworks (COFs) are considered among the most potential crystalline porous materials for solar-driven hydrogen production. However, it is usually necessary to introduce noble metal cocatalysts to boost the hydrogen evolution capacity of COFs. In this work, a unique S-scheme heterojunction structured TtTfp-COF/NiS composite material was effectively developed by growing metal sulfide on the typical two-dimensional covalent organic framework TtTfp-COF through a simple solvothermal synthesis method. In this structure, linear structure of rod-like NiS is more stable and convenient for further surface modification. It also provides key active sites and promotes efficient electron transfer, significantly enhancing the hydrogen evolution efficiency. The covalent organic framework enhances charge carrier transport efficiency by controlling the spatial organization of precursors and ligands. It is indicated by the experimental findings that a hydrogen evolution rate of 5978 μmol·g−1·h−1 can be achieved for the NT-20 sample, which about 11.5 times higher than that of the initial TtTfp-COF (520 μmol·g−1·h−1). In addition, the material exhibits a notable quantum efficiency of 1.96% when exposed to 420 nm illumination. Both experimental results and theoretical analyses have been confirmed to improve the hydrogen evolution rate via photocatalysis and the charge transfer mechanism within the S-scheme heterojunction has been thoroughly elucidated. The design and development of non-precious metal COF-based photocatalysts are provided with new insights in this article, and new ideas for the construction of S-scheme heterojunctions are offered by the synergistic combination of inorganic and organic materials in photocatalysis.
2025, 41(12): 100155
doi: 10.1016/j.actphy.2025.100155
Abstract:
Designing and establishing dual-functional S-scheme heterojunction photocatalysts with efficient separation of photoproduced carriers and intense oxidation/reduction capabilities holds immense practical value for their photocatalytic application in energy conversion and environmental purification. Herein, a novel series of x% CoWO4/CdIn2S4 (x% reflects the weight ratio of CWO to CIS; x = 10, 20, 30, 40 and 50) composites have been systematically designed and synthesized via electrospinning technique and hydrothermal methods. Their photocatalytic properties were assessed through HCHO removal and H2 generation under visible light. As anticipated, the optimized 30% CWO/CIS heterojunction presented an outstanding H2 generation performance of 865.14 μmol g−1 h−1 with AQE = 3.6% at λ = 420 nm, and achieved a 69% removal percentage for HCHO within 1 h. Meanwhile, the pathway of HCHO degradation was presented based on in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) technique. The great catalytic performance was primarily ascribed to the enhancement in the visible-light absorption, number of active sites, and the construction of S-scheme heterojunction. Furthermore, the S-scheme charge transfer mechanism for the CWO/CIS catalyst system has been confirmed by in situ X-ray photoelectron spectroscopy (in situ XPS), electron spin resonance data, radical capturing experiments, and density functional theory (DFT) calculations. This research contributes valuable understanding for the systematic design and development of bifunctional S-scheme heterojunctions for gaseous pollutants removal and H2 production.![]()
Designing and establishing dual-functional S-scheme heterojunction photocatalysts with efficient separation of photoproduced carriers and intense oxidation/reduction capabilities holds immense practical value for their photocatalytic application in energy conversion and environmental purification. Herein, a novel series of x% CoWO4/CdIn2S4 (x% reflects the weight ratio of CWO to CIS; x = 10, 20, 30, 40 and 50) composites have been systematically designed and synthesized via electrospinning technique and hydrothermal methods. Their photocatalytic properties were assessed through HCHO removal and H2 generation under visible light. As anticipated, the optimized 30% CWO/CIS heterojunction presented an outstanding H2 generation performance of 865.14 μmol g−1 h−1 with AQE = 3.6% at λ = 420 nm, and achieved a 69% removal percentage for HCHO within 1 h. Meanwhile, the pathway of HCHO degradation was presented based on in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) technique. The great catalytic performance was primarily ascribed to the enhancement in the visible-light absorption, number of active sites, and the construction of S-scheme heterojunction. Furthermore, the S-scheme charge transfer mechanism for the CWO/CIS catalyst system has been confirmed by in situ X-ray photoelectron spectroscopy (in situ XPS), electron spin resonance data, radical capturing experiments, and density functional theory (DFT) calculations. This research contributes valuable understanding for the systematic design and development of bifunctional S-scheme heterojunctions for gaseous pollutants removal and H2 production.
2025, 41(12): 100158
doi: 10.1016/j.actphy.2025.100158
Abstract:
S-scheme heterojunctions have garnered significant attention for efficient photocatalytic H2 evolution due to their superior charge separation and maximized redox potential. In this study, we developed a novel pyrene-benzothiadiazole conjugated polymer (YBTPy) through Yamamoto coupling, followed by the in situ deposition of CdS nanoparticles via a solvothermal method to construct a CdS/YBTPy S-scheme heterojunction photocatalyst. The optimized composite, designated as CP5, demonstrated a hydrogen production rate of 5.01 mmol h−1 g−1, representing a 4.2-fold enhancement compared to pristine CdS (1.20 mmol h−1 g−1). The characteristic S-scheme charge transfer pathway at the heterojunction interface was elucidated using in situ irradiated X-ray photoelectron spectroscopy in conjunction with Kelvin probe force microscopy. Additionally, femtosecond transient absorption spectroscopy was employed to investigate the dynamics of photogenerated charge carriers. This work provides a new theoretical foundation for the design of organic–inorganic hybrid S-scheme photocatalytic systems.![]()
S-scheme heterojunctions have garnered significant attention for efficient photocatalytic H2 evolution due to their superior charge separation and maximized redox potential. In this study, we developed a novel pyrene-benzothiadiazole conjugated polymer (YBTPy) through Yamamoto coupling, followed by the in situ deposition of CdS nanoparticles via a solvothermal method to construct a CdS/YBTPy S-scheme heterojunction photocatalyst. The optimized composite, designated as CP5, demonstrated a hydrogen production rate of 5.01 mmol h−1 g−1, representing a 4.2-fold enhancement compared to pristine CdS (1.20 mmol h−1 g−1). The characteristic S-scheme charge transfer pathway at the heterojunction interface was elucidated using in situ irradiated X-ray photoelectron spectroscopy in conjunction with Kelvin probe force microscopy. Additionally, femtosecond transient absorption spectroscopy was employed to investigate the dynamics of photogenerated charge carriers. This work provides a new theoretical foundation for the design of organic–inorganic hybrid S-scheme photocatalytic systems.
2025, 41(12): 100159
doi: 10.1016/j.actphy.2025.100159
Abstract:
While H2 features high energy density, environmental friendliness, and renewability, its efficient production is limited by the sluggish kinetics of the oxygen evolution reaction (OER). Here, we report a Pt@PtNi3 core@shell alloy electrocatalyst that, through Ni incorporation, modulates the occupancy of Pt 5d antibonding orbitals and simultaneously enhances both hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) activities. The optimized Pt@PtNi3-500 delivers an ultralow overpotential of 21 mV at 10 mA cm-2 for HER under acidic conditions and a low onset potential of 1.27 V for UOR under alkaline conditions, surpassing monometallic Pt and Ni counterparts. When employed in an asymmetric acid-alkaline electrolyzer (HER/UOR), Pt@PtNi3-500 achieves a 68.3% reduction in electrical energy consumption for H2 production compared to traditional alkaline water splitting (HER/OER). Mechanistic investigations reveal that appropriate Ni incorporation in Pt@PtNi3 increases the occupancy of Pt 5d–H 1s antibonding orbitals, which not only reinforces H+ adsorption but also weakens the overly strong H* binding. Simultaneously, it reduces the energy barrier for *NH2 dehydrogenation, thereby synergistically accelerating both H2 generation and urea decomposition. This work provides new insights into the design of alloy electrocatalysts for high-efficiency H2 production.![]()
While H2 features high energy density, environmental friendliness, and renewability, its efficient production is limited by the sluggish kinetics of the oxygen evolution reaction (OER). Here, we report a Pt@PtNi3 core@shell alloy electrocatalyst that, through Ni incorporation, modulates the occupancy of Pt 5d antibonding orbitals and simultaneously enhances both hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) activities. The optimized Pt@PtNi3-500 delivers an ultralow overpotential of 21 mV at 10 mA cm-2 for HER under acidic conditions and a low onset potential of 1.27 V for UOR under alkaline conditions, surpassing monometallic Pt and Ni counterparts. When employed in an asymmetric acid-alkaline electrolyzer (HER/UOR), Pt@PtNi3-500 achieves a 68.3% reduction in electrical energy consumption for H2 production compared to traditional alkaline water splitting (HER/OER). Mechanistic investigations reveal that appropriate Ni incorporation in Pt@PtNi3 increases the occupancy of Pt 5d–H 1s antibonding orbitals, which not only reinforces H+ adsorption but also weakens the overly strong H* binding. Simultaneously, it reduces the energy barrier for *NH2 dehydrogenation, thereby synergistically accelerating both H2 generation and urea decomposition. This work provides new insights into the design of alloy electrocatalysts for high-efficiency H2 production.
2025, 41(12): 100160
doi: 10.1016/j.actphy.2025.100160
Abstract:
Covalent organic frameworks (COFs), recognized for their precisely tunable microstructures and high surface area, are promising photocatalysts for H2O2 production. However, the critical influence of pH on the stability of COF during the photocatalytic H2O2 production remains poorly understood. In this work, the photocatalytic H2O2 production performance of an imine-linked COF is significantly enhanced through a simple protonation strategy. Crucially, the protonated COF exhibits excellent stability under weakly acidic conditions (pH ≥ 3), but undergoes irreversible hydrolyzed under strongly acidic conditions (pH < 3). The protonation occurs specifically at the nitrogen atoms of imine units and serves a dual function: it suppresses ultrafast charge recombination (as revealed by femtosecond transient absorption spectroscopy) and directly provides a proton source for H2O2 generation. Moreover, fluoride ions (F−) are introduced into the photocatalytic system to further improve the photocatalytic H2O2 production rate. The strong electronegativity of F− facilitates electron transfer from COF to F−, thus realizing the spatial separation of photogenerated carriers. Mechanistic studies confirm that H2O2 production follows a two-electron oxygen reduction reaction pathway. These findings elucidate the pH-dependent stability and activity of protonated COFs, provide fundamental insights into charge carrier dynamics, and establishe design principles to develop highly efficient and stable COF-based photocatalysts for solar-driven H2O2 generation.![]()
Covalent organic frameworks (COFs), recognized for their precisely tunable microstructures and high surface area, are promising photocatalysts for H2O2 production. However, the critical influence of pH on the stability of COF during the photocatalytic H2O2 production remains poorly understood. In this work, the photocatalytic H2O2 production performance of an imine-linked COF is significantly enhanced through a simple protonation strategy. Crucially, the protonated COF exhibits excellent stability under weakly acidic conditions (pH ≥ 3), but undergoes irreversible hydrolyzed under strongly acidic conditions (pH < 3). The protonation occurs specifically at the nitrogen atoms of imine units and serves a dual function: it suppresses ultrafast charge recombination (as revealed by femtosecond transient absorption spectroscopy) and directly provides a proton source for H2O2 generation. Moreover, fluoride ions (F−) are introduced into the photocatalytic system to further improve the photocatalytic H2O2 production rate. The strong electronegativity of F− facilitates electron transfer from COF to F−, thus realizing the spatial separation of photogenerated carriers. Mechanistic studies confirm that H2O2 production follows a two-electron oxygen reduction reaction pathway. These findings elucidate the pH-dependent stability and activity of protonated COFs, provide fundamental insights into charge carrier dynamics, and establishe design principles to develop highly efficient and stable COF-based photocatalysts for solar-driven H2O2 generation.
2025, 41(12): 100168
doi: 10.1016/j.actphy.2025.100168
Abstract:
Donor-π-Acceptor (D-π-A) conjugated polymers represent an emerging class of materials featuring alternating electron donor (D), π-bridge (π), and electron acceptor (A) units, which exhibit significant potential in enhancing visible-light absorption and optimizing charge separation and redistribution. To overcome the limitations of graphitic carbon nitride (g-C3N4) while capitalizing on the structural merits of D-π-A systems, a series of 4-aromatic amine derivatives modified g-C3N4 photocatalysts was designed and synthesized through precise molecular level regulation with tailored local electron delocalization. This strategy allows for a systematic investigation of the relationship between electron delocalization extent and photocatalytic H2O2 production. Furthermore, the electron-withdrawing induction effect for regulating electron delocalization results in a substantial enhancement of photoinduced electron transfer to surface reactive sites. The as-synthesized optimum photocatalyst exhibits a remarkable H2O2 production performance, which is 30.44 times higher than that of the pristine g-C3N4. The mechanism study reveals that the photocatalytic H2O2 production in D-π-A-type g-C3N4 proceeds primarily via a two-electron oxygen reduction reaction (ORR).![]()
Donor-π-Acceptor (D-π-A) conjugated polymers represent an emerging class of materials featuring alternating electron donor (D), π-bridge (π), and electron acceptor (A) units, which exhibit significant potential in enhancing visible-light absorption and optimizing charge separation and redistribution. To overcome the limitations of graphitic carbon nitride (g-C3N4) while capitalizing on the structural merits of D-π-A systems, a series of 4-aromatic amine derivatives modified g-C3N4 photocatalysts was designed and synthesized through precise molecular level regulation with tailored local electron delocalization. This strategy allows for a systematic investigation of the relationship between electron delocalization extent and photocatalytic H2O2 production. Furthermore, the electron-withdrawing induction effect for regulating electron delocalization results in a substantial enhancement of photoinduced electron transfer to surface reactive sites. The as-synthesized optimum photocatalyst exhibits a remarkable H2O2 production performance, which is 30.44 times higher than that of the pristine g-C3N4. The mechanism study reveals that the photocatalytic H2O2 production in D-π-A-type g-C3N4 proceeds primarily via a two-electron oxygen reduction reaction (ORR).
2025, 41(12): 100174
doi: 10.1016/j.actphy.2025.100174
Abstract:
In this paper, a dual-function TiO2/CdIn2S4 S-scheme heterojunction photocatalyst was fabricated through electrospinning and hydrothermal methods for hydrogen generation coupled with the selective oxidation of vanillyl alcohol (VAL) to vanillin (VN). The results indicate that the hybrid material containing 0.5 wt% CdIn2S4 possesses the best photocatalytic performance. The hydrogen generation rate reaches 403.36 μmol g−1 h−1. Meanwhile, the conversion of VAL is measured to be 90.99%. The results of experiments and density functional theory (DFT) calculations elucidate that the S-scheme heterojunction enhances the rate of charge migration and improves the efficiency of charge separation. In this system, the photoexcited holes with stronger oxidation capacity are reserved to catalyze the conversion of VAL into VN, while the photoexcited electrons with stronger reduction capacity are utilized to generate hydrogen. This study introduces a promising strategy that combines photocatalytic hydrogen generation with the selective conversion of organic compounds, offering novel insights into the development of innovative photocatalysts for effective solar energy utilization.![]()
In this paper, a dual-function TiO2/CdIn2S4 S-scheme heterojunction photocatalyst was fabricated through electrospinning and hydrothermal methods for hydrogen generation coupled with the selective oxidation of vanillyl alcohol (VAL) to vanillin (VN). The results indicate that the hybrid material containing 0.5 wt% CdIn2S4 possesses the best photocatalytic performance. The hydrogen generation rate reaches 403.36 μmol g−1 h−1. Meanwhile, the conversion of VAL is measured to be 90.99%. The results of experiments and density functional theory (DFT) calculations elucidate that the S-scheme heterojunction enhances the rate of charge migration and improves the efficiency of charge separation. In this system, the photoexcited holes with stronger oxidation capacity are reserved to catalyze the conversion of VAL into VN, while the photoexcited electrons with stronger reduction capacity are utilized to generate hydrogen. This study introduces a promising strategy that combines photocatalytic hydrogen generation with the selective conversion of organic compounds, offering novel insights into the development of innovative photocatalysts for effective solar energy utilization.
2025, 41(12): 100190
doi: 10.1016/j.actphy.2025.100190
Abstract:
The construction of S-scheme heterojunction photocatalysts has emerged as a promising strategy to address the urgent need for efficient antibiotic wastewater remediation. However, persistent challenges in achieving interfacial intimacy and precise charge transfer regulation between semiconductors have hindered their practical implementation. In this work, we engineered a hierarchical Cd0.5Zn0.5S/BiOBr S-scheme heterojunction via a controlled solvothermal synthesis, where BiOBr microspheres serve as the core, and Cd0.5Zn0.5S nanoparticles form a conformal shell. This architecture ensures maximal interfacial contact and directional charge dynamics, critical for optimizing photocatalytic efficiency. The optimized heterojunction exhibits superior catalytic performance, achieving tetracycline (TC) degradation rate constants 3.3- and 1.6-fold greater than pristine BiOBr and Cd0.5Zn0.5S, respectively. This enhancement stems from the synergistic interplay of efficient charge separation and preserved redox capacities inherent to the S-scheme mechanism. Furthermore, the TC degradation process and mechanism were elucidated. This study provides a new perspective on developing defective S-scheme heterojunctions for antibiotic wastewater purification with high performance.![]()
The construction of S-scheme heterojunction photocatalysts has emerged as a promising strategy to address the urgent need for efficient antibiotic wastewater remediation. However, persistent challenges in achieving interfacial intimacy and precise charge transfer regulation between semiconductors have hindered their practical implementation. In this work, we engineered a hierarchical Cd0.5Zn0.5S/BiOBr S-scheme heterojunction via a controlled solvothermal synthesis, where BiOBr microspheres serve as the core, and Cd0.5Zn0.5S nanoparticles form a conformal shell. This architecture ensures maximal interfacial contact and directional charge dynamics, critical for optimizing photocatalytic efficiency. The optimized heterojunction exhibits superior catalytic performance, achieving tetracycline (TC) degradation rate constants 3.3- and 1.6-fold greater than pristine BiOBr and Cd0.5Zn0.5S, respectively. This enhancement stems from the synergistic interplay of efficient charge separation and preserved redox capacities inherent to the S-scheme mechanism. Furthermore, the TC degradation process and mechanism were elucidated. This study provides a new perspective on developing defective S-scheme heterojunctions for antibiotic wastewater purification with high performance.
2025, 41(12): 100176
doi: 10.1016/j.actphy.2025.100176
Abstract:
The harmful effects of the energy crisis and environmental degradation are becoming increasingly severe, which urgently demands the advancement of eco-friendly and sustainable production techniques. Direct conversion of abundant solar energy into chemical energy represents a promising green and efficient technological solution. In this process, photocatalysts play a pivotal role. Covalent organic frameworks (COFs), a class of porous materials interconnected by covalent bonds, exhibit exceptional potential for photocatalysis due to their high surface area, excellent crystallinity, and tunable structures. This review discusses the roles of compositional regulation in enhancing the photocatalytic performance of COFs, including modulating light absorption, increasing active sites, promoting exciton dissociation, and improving carrier separation. Furthermore, computational and mechanistic characterization methods are also discussed. More importantly, the key strategies in compositional regulation, such as heteroatom engineering, metal single-atom engineering, ion engineering, functional group engineering, Donor-Acceptor (D-A) molecular engineering, side chain engineering, multi-component engineering, isomerism engineering, conjugate bridge engineering, single-molecule junction engineering, and interlayer engineering, are carefully summarized. Moreover, their diversified modification strategies and applications in photocatalytic hydrogen (H2) evolution, hydrogen peroxide (H2O2) production, and carbon dioxide (CO2) reduction are also addressed. Finally, the current challenges and future opportunities for COF-based photocatalysis are outlined.![]()
The harmful effects of the energy crisis and environmental degradation are becoming increasingly severe, which urgently demands the advancement of eco-friendly and sustainable production techniques. Direct conversion of abundant solar energy into chemical energy represents a promising green and efficient technological solution. In this process, photocatalysts play a pivotal role. Covalent organic frameworks (COFs), a class of porous materials interconnected by covalent bonds, exhibit exceptional potential for photocatalysis due to their high surface area, excellent crystallinity, and tunable structures. This review discusses the roles of compositional regulation in enhancing the photocatalytic performance of COFs, including modulating light absorption, increasing active sites, promoting exciton dissociation, and improving carrier separation. Furthermore, computational and mechanistic characterization methods are also discussed. More importantly, the key strategies in compositional regulation, such as heteroatom engineering, metal single-atom engineering, ion engineering, functional group engineering, Donor-Acceptor (D-A) molecular engineering, side chain engineering, multi-component engineering, isomerism engineering, conjugate bridge engineering, single-molecule junction engineering, and interlayer engineering, are carefully summarized. Moreover, their diversified modification strategies and applications in photocatalytic hydrogen (H2) evolution, hydrogen peroxide (H2O2) production, and carbon dioxide (CO2) reduction are also addressed. Finally, the current challenges and future opportunities for COF-based photocatalysis are outlined.
2025, 41(12): 100185
doi: 10.1016/j.actphy.2025.100185
Abstract:
Recent advances in tin disulfide (SnS2)-based heterojunctions have demonstrated their great potential for photocatalysis and sensing applications, owing to their optimal bandgap (2.0–2.3 eV), remarkable stability, environmental compatibility, and outstanding surface reactivity. Despite these advantages, a comprehensive review systematically addressing this emerging field remains lacking. This review first outlines the state-of-the-art synthesis strategies for SnS2 heterostructures. It then critically evaluates their photocatalytic performance in key applications, including hydrogen evolution, environmental remediation, and hydrogen peroxide production. The gas-sensing capabilities are subsequently analyzed, with special emphasis on nitrogen dioxide and ammonia detection. Mechanistic studies reveal that the enhanced performance originates from tailored heterojunction designs: S-scheme configurations significantly boost charge separation in photocatalysis; n-n/p-n junctions optimize active site distribution and gas adsorption in sensing applications. The interfacial synergy between SnS2 and coupled semiconductors is identified as the key factor governing performance improvements. Finally, some conclusions and perspectives as well as future challenges are presented.![]()
Recent advances in tin disulfide (SnS2)-based heterojunctions have demonstrated their great potential for photocatalysis and sensing applications, owing to their optimal bandgap (2.0–2.3 eV), remarkable stability, environmental compatibility, and outstanding surface reactivity. Despite these advantages, a comprehensive review systematically addressing this emerging field remains lacking. This review first outlines the state-of-the-art synthesis strategies for SnS2 heterostructures. It then critically evaluates their photocatalytic performance in key applications, including hydrogen evolution, environmental remediation, and hydrogen peroxide production. The gas-sensing capabilities are subsequently analyzed, with special emphasis on nitrogen dioxide and ammonia detection. Mechanistic studies reveal that the enhanced performance originates from tailored heterojunction designs: S-scheme configurations significantly boost charge separation in photocatalysis; n-n/p-n junctions optimize active site distribution and gas adsorption in sensing applications. The interfacial synergy between SnS2 and coupled semiconductors is identified as the key factor governing performance improvements. Finally, some conclusions and perspectives as well as future challenges are presented.
