Single-component ZnIn2S4 (ZIS) exhibits rapid charge recombination, resulting in low photocatalytic efficiency. To address this issue, the construction of an S-scheme heterojunction is a feasible strategy. Herein, a ZIS/dopamine (PDA) S-scheme heterojunction photocatalyst was successfully fabricated by depositing PDA onto the surface of ZIS nanoflowers. The optimized ZIS/PDA composite shows a significantly improved H2 production rate compared to pure ZIS and PDA. In situ irradiated X-ray photoelectron spectroscopy provides steady-state spectral evidence of S-scheme electron transfer from ZIS to PDA upon photoexcitation. Furthermore, transient spectral evidence for the ZIS/PDA S-scheme heterojunction is revealed via femtosecond transient absorption spectroscopy. Analysis of the charge dynamics in the ZIS component identifies an additional ultrafast lifetime component in the ZIS/PDA composites. This newly identified component is primarily attributable to the S-scheme interfacial electron transfer channel. The S-scheme electron transfer process gradually accelerates with increasing PDA concentration, ultimately reaching an optimal interfacial electron transfer lifetime of 0.9 ps. This ultrafast electron transfer dynamics facilitates the participation of photogenerated charge carriers in photocatalytic H2 evolution. Overall, this study provides new insights into the transient spectral analysis of S-scheme photocatalysts.
The practical application of aqueous zinc-ion batteries is critically hindered by the instability of the zinc metal anode, which suffers from uncontrollable dendrite growth and detrimental side reactions. Conventional electrolyte additives often focus solely on homogenizing the zinc-ion flux, while neglecting the pivotal role of crystallographic regulation. Herein, we propose a fundamental strategy to manipulate zinc deposition behavior through selective molecular adsorption. We introduce 2-aminoethylphosphonic acid (AEP) as a novel electrolyte additive that preferentially adsorbs onto the (100) and (101) crystal planes of zinc, as confirmed by experimental evidence from electric double-layer capacitance measurements, and theoretical DFT calculations, which reveal a lower adsorption energy on the (002) facet. Consequently, the AEP-modified electrolyte enables a densely packed zinc morphology and a significantly optimized interface, which collectively contribute to markedly enhanced electrode kinetics and cycling stability. The improved negative electrolyte enables the zinc-iodine flow battery (ZIFB) to operate for 600 h (1500 cycles) with a high energy efficiency (> 83%) at 80 mA/cm2. This work underscores the critical importance of crystallographic engineering via selective molecular adsorption. The mechanistic insights gained into the dual regulation of solvation structure and interfacial growth provide a new design principle for advanced electrolytes targeting highly reversible metal anodes.
A critical challenge in solar-driven water splitting is developing efficient photocatalysts for the oxygen evolution reaction without relying on metal cocatalysts. Herein, we address this challenge by employing amide linkage engineering in donor–acceptor covalent organic polymers (COPs). Two such polymers, COP-M and COP-I, were synthesized via straightforward sol–gel condensation of acyl chlorides (donor) and melamine (acceptor). The inherent donor–acceptor structure of these COPs imparts an appropriate bandgap (~ 2.9 eV), facilitating effective intramolecular charge separation. Remarkably, these metal-free COPs exhibit intrinsic visible-light-driven oxygen evolution activity without any metal cocatalysts. Their performance can be enhanced approximately fivefold by introducing Co2+, with COP-M achieving an optimal O2 evolution rate of 106 μmol/h. Both experimental and theoretical analyses suggest that the polar amide bond enhances surface hydrophilicity and modulates the thermodynamic barrier for initial water activation. Additionally, enhanced charge separation and transfer kinetics within the symmetrical donor–acceptor architecture of COP-M underscore its enhanced performance. This study emphasizes the collaborative role of amide linkages and donor–acceptor motifs in designing metal-free polymer photocatalysts, offering a strategy for artificial photosynthesis.
The high cost and scarcity of noble metal anode catalysts significantly hinder the commercialization of proton exchange membrane (PEM) water electrolyzers. These limitations have inspired the development of non-noble metal oxygen evolution reaction (OER) catalysts with high activity and stability for large-scale green hydrogen production. Herein, we report the synthesis of a Ce-modulated cobalt (II, III) oxide (CeCo3O4) OER catalyst via metal–organic framework-assisted electrodeposition and low-temperature annealing. This catalyst enables the construction of three-dimensional (3D) cubic architectures on carbon cloth (CC) via controllable defect chemistry, where Ce incorporation effectively modulates the electronic structure of Co sites by regulating the Co3+/Co2+ ratio and oxygen vacancies, thereby stabilizing the catalyst, even under acidic OER conditions. The resulting optimized 3D-CeCo3O4//CC catalyst delivers an overpotential of 202 mV at a current density of 10 mA/cm2 in 0.5 mol/L sulfuric acid and exhibits durable operation with minimal potential drift over 100 h. When implemented as the anode of a practical PEM electrolyzer featuring a Pt/C cathode (1 mg/cm2), the device delivers a current density of 100 mA/cm2 at 1.788 V, maintaining stable operation at 50 mA/cm2 for 15 h with a voltage fluctuation. This performance surpasses those of most reported non-noble metal OER catalysts, with an efficiency gap that remains relative to those of previous state-of-the-art noble metal-based systems. These results reveal that Ce-induced electronic modulation and oxygen vacancy engineering synergistically enhance the acidic OER activity and stability of Co3O4, offering a viable, scalable strategy for developing non-noble metal OER catalysts for practical PEM water electrolyzers.
Atomic force microscopy (AFM) has become an essential tool for probing electrode surfaces, nanoscale reactions, and material properties in electrochemical research. By exploiting tip–sample interactions, AFM enables ultrahigh-resolution imaging of surface topography and enables the in situ monitoring of structural and morphological evolution during electrochemical processes. This review strategically explores two pivotal domains—energy-related electrocatalysis and batteries—to elucidate the microscopic mechanisms behind phenomena, such as lithium deposition/stripping, solid–electrolyte interphase formation, and key reactions, including carbon dioxide electroreduction and hydrogen evolution reduction. Within these contexts, AFM-based force spectroscopy (e.g., force–displacement curves) provides insights into the mechanical properties of electrodes and interfacial layers, offering critical data for material design and optimization. Furthermore, electrical modes, including Kelvin probe force microscopy and conductive AFM, enable the nanoscale characterization of local conductivity and surface potential. Complementing these, piezoresponse force microscopy probes electromechanical coupling and ferroelectric domain dynamics, revealing how local polarization and strain govern ion transport and catalytic activity. Together, these techniques advance electrochemical studies from macroscopic averaging toward in situ, spatially resolved, and heterogeneous mechanistic analysis. The fundamental insights gained from this review deepen our understanding of electrochemical processes and offer a promising avenue for advancing related fields, such as supercapacitors, fuel cells, and photoelectrochemical systems. This review systematically examines various AFM operating modes to highlight recent advances in the nanoscale characterization of electrode materials for diverse energy-related electrocatalysis and battery systems. Furthermore, it critically discusses current limitations, emerging challenges, and future perspectives.
Harnessing solar energy through photocatalysis offers a promising pathway for sustainable energy conversion and environmental remediation. Central to this progress is the development of efficient photocatalysts capable of activating inert N2 molecules under mild conditions. Recently, dual-atom catalysts (DACs) have emerged as a transformative class of materials that bridge the gap between single-atom and nanoparticle catalysts by providing synergistic bimetallic active sites with maximized atomic utilization. This review concisely summarizes recent advances in the coordination microenvironment, structural design, and catalytic mechanisms of transition metal-based dual-atom catalysts (TM-DACs) for photocatalytic N2 conversion. Particular emphasis is placed on how electronic coupling, metal–metal interactions, and coordination configuration of TM-DACs govern charge transfer dynamics, adsorption behavior, and reaction kinetics during the N2 reduction process. Synthesis strategies, characterization techniques, and mechanistic pathways of TM-DACs are comprehensively discussed, highlighting their advantages over single-atom systems. Furthermore, emerging trends and challenges in developing noble metal-free, earth-abundant DACs for efficient NH3 production are outlined. This review aims to provide fundamental insights and design principles for constructing next-generation TM-DACs for highly efficient and sustainable photocatalytic applications.
Schematic of the coordination microenvironment and dual-metal synergy in transition metal-based dual-atom catalysts (TM-DACs) for photocatalytic N2 fixation. Design strategies, active site interactions, charge transfer pathways, and reaction mechanisms are highlighted to guide the development of effective and sustainable photocatalysts for NH3 production.
Chiral assembly endows perovskite materials with well-defined structural chirality and optical anisotropy, creating unique opportunities for multidimensional modulation in optoelectronic applications. Recent advances have demonstrated effective amplification of chiral signals, band structure engineering, and enhanced spin–orbit coupling through diverse strategies, including template-guided assembly, ligand-induced assembly, and several emerging approaches. This review highlights the latest progress in chiral perovskites for circularly polarized light-emitting devices, polarization-sensitive photodetectors, polarization imaging, optical communication and encryption, and spintronic and quantum information applications. Particular attention is devoted to the mechanistic correlations between assembly strategies and key performance parameters of chiral perovskites, such as dissymmetry factors, photoluminescence quantum yields, spin polarization degrees, and device stability. Representative studies are analyzed to elucidate the interplay between material architecture and device functionality. Despite remarkable progress, challenges remain, including limited stability, chirality retention, interface engineering, and scalable fabrication. Looking forward, the integration of multiple assembly strategies with multiscale theoretical modeling and machine learning-assisted design is anticipated to accelerate the translation of chiral perovskites from laboratory demonstrations to real-world applications in advanced optoelectronic devices, secure communication systems, and quantum information technologies.
Lithium–sulfur batteries (LSBs) have attracted considerable research attention owing to their exceptional theoretical energy density. However, their practical application remains impeded by the shuttle effect of lithium polysulfides (LiPSs) and sluggish redox kinetics. The rational design of catalysts capable of accelerating sulfur species conversion represents a pivotal strategy for achieving high-performance LSBs. Covalent organic frameworks (COFs) have emerged as promising catalyst candidates owing to their intrinsic structural and functional tunability. Through judicious molecular engineering of chemical composition and spatial architecture, the electronic structure of COFs can be precisely regulated, thereby enhancing interfacial charge transfer between COFs and LiPSs and facilitating sulfur redox reactions. This review systematically delineates three fundamental strategies for electronic structure regulation of COFs and comprehensively analyzes their governing effects on bandgap engineering, charge redistribution, and surface electronic states. Furthermore, it elucidates the multifaceted mechanistic roles of these electronic characteristics in critical LSB processes, encompassing LiPS adsorption, interfacial charge transfer, and mitigation of energy barriers in sulfur-related reactions. Finally, this review outlines the principal challenges in material design and performance optimization while offering a forward-looking perspective on the developmental trajectory of COF-based catalysts for next-generation high-performance LSBs.