Nickel-based catalysts hold significant promise for efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) due to their dynamic reconstruction capability. However, uncontrolled reconstruction promotes lattice oxygen participation, triggering the destructive lattice oxygen-mediated mechanism (LOM) that causes rapid catalyst disintegration at industrial current densities. Herein, we resolve the challenge through Fe doping-enabled selective adsorbate evolution mechanism (AEM) pathway engineering in a Ni₂P/NiMoO₄ heterostructure (Fe-Ni₂P/NiMoO₄). During OER, Fe doping triggers deep reconstruction into Ni(Fe)OOH while suppressing the LOM via electronic modulation, yielding an AEM with optimized OH* adsorption. This mechanism-selective design delivers exceptional bifunctional performance: 140 mV (HER) and 256 mV (OER) overpotentials at 100 mA cm⁻², sustained stability at 200 mA cm⁻² for 100 h (HER and OER) and 50 mA cm⁻² for 100 h (overall water splitting). Mechanistic studies reveal Fe doping's dual role: (i) accelerating reconstruction kinetics to form Ni(Fe)OOH as the AEM-active phase and (ii) stabilizing the Fe-Ni₂P conductive backbone by eliminating oxygen-loss pathways. This work pioneers mechanism-selective reconstruction as a design principle for industrial electrocatalysts, moving beyond empirical activity optimization toward rational pathway control.

Retroreflectors that scatter the incident electromagnetic (EM) wave along the incoming direction are widely used for backscattering enhancement and intensifying echo signals for many applications, including collision avoidance systems, lifesaving, and satellite communications. Recently, metasurface has been applied for achieving retroreflectors with extremely low profile, but they always require a predetermined incident angle information and have limitations for wide-angle and polarization-independent incidences. Here, we propose an adaptive retroreflector composed of an active anisotropic metasurface for EM waves incidences of wide-angle and multiple polarizations. The reflective phases of the constituent meta-atoms under orthogonal polarized incidences can be controlled independently and tuned continuously by individually altering the anisotropic characteristic of the meta-atoms. The proposed metasurface first estimates the direction of arrival (DOA) based on a pre-trained artificial neural network with space–time coding–modulated metasurfaces and then modulates the phase gradient accordingly to achieve the adaptive retroreflection. As a proof of concept, we construct a tunable metasurface and experimentally demonstrated at microwave frequency that high-efficient on-demand adaptive retroreflection for multiple polarizations can be achieved over a continuous incident angle range from −50° to +50°. The proposed retroreflector can be extended to other frequencies and may find promising applications in communication systems, remote sensing, and radar scattering enhancement techniques.

Developing structurally well-defined, noble-metal-free photocatalysts that combine high stability with efficient charge utilization remains a key challenge for sustainable hydrogen (H₂) production. Herein, we report isoreticular two-dimensional metal–covalent organic frameworks (MCOFs) termed Cu₃-PDA, Cu₃-NDA, and Cu₃-ADA (PDA = 1,4-phenylenediamine; NDA = 2,6-naphthalenediamine; ADA = 2,6-anthracenediamine), assembled from preorganized planar trinuclear Cu₃-cluster nodes and aromatic diamine linkers with systematically extended π-conjugation. All three frameworks preserve identical topology and stacking while allowing a single-variable modulation of linker length and conjugation to tune light harvesting and charge separation. Under visible light irradiation, the moderately conjugated Cu₃-NDA delivers exceptional noble-metal-free H₂ evolution of 31,328 μmol g⁻¹ h⁻¹, 4-fold and 2.7-fold higher than Cu₃-PDA and Cu₃-ADA, respectively, ranking among the best COF-based photocatalysts. Photoelectrochemical measurements and theoretical analyses indicate that an appropriately extended π-extension promotes delocalized electron transport and suppresses recombination, achieving the best balance between carrier separation and interfacial transfer. This work establishes a tractable platform to correlate conjugation engineering with photocatalytic activity in MCOFs and offers a general design paradigm based on cluster-node engineering and reticular conjugation control.

Nitrophenols are environmental pollutants found in waterways and the atmosphere, which can be a significant source of nitrous acid under UV light. In this work, we investigate nitrophenols in aqueous solution upon UV irradiation with a suite of steady-state and ultrafast electronic and vibrational spectroscopies. We find that ortho- and para-nitrophenol are highly sensitive to zinc as a heterogeneous catalyst, accelerating the transformation of nitrophenols with/without UV light. Steady-state absorption, femtosecond stimulated Raman spectroscopy (FSRS), and quantum calculations reveal that UV light triggers excited-state intramolecular proton transfer to form an aci-nitro intermediate that is stabilized by zinc. We photoexcite the metastable intermediate and obtain femtosecond transient absorption signatures. The redshifted ground-state absorption and lengthened excited-state lifetime of the aci-nitro intermediate are beneficial for photocatalytic removal with irradiation greater than 400 nm. Furthermore, the water O–H stretching band is tracked by FSRS to unveil a uniquely active role of water during the catalytic reaction of ortho-nitrophenol, rationalizing its reduced photosensitivity in organic solvents such as methanol. These neat treatment strategies are also applied to para- and meta-nitrophenol and nitrophenolate. Our mechanistic insights into the photosensitivity of nitrophenols can inspire more effective cost-efficient treatment strategies for atmospheric aerosols and water systems.

Persistent and stable radicals remain challenging to generate via photoinduction, despite their vast potential in magnetics and energy storage. Trisubstituted amines offer a promising platform for photoinduced radicals, but rapid charge recombination prevents the formation of nitrogen radical cations. Herein, we report a series of BN-azepines featuring a negatively curved heptagon that enforces a twisted, rigid donor–acceptor architecture, enabling solution-stable radicals via photoinduced charge separation. In the twisted heptagon backbone, boron captures an electron from nitrogen upon photoexcitation, yielding a charge-separated singlet state, and the small singlet–triplet energy gap further facilitates the formation of a longer-lived triplet charge-separated state. This provides sufficient time for the boron-localized electron to be lost, ultimately generating the nitrogen radical cation. Importantly, these BN-azepines also exhibit anti-Kasha emission and singlet oxygen sensitization. This work establishes a novel molecular design strategy for photoinduced radical generation and positions BN-azepines as promising candidates for future optoelectronic applications.

Dynamic electromagnetic (EM) wavefront manipulation is pivotal and holds broad application prospects for advancing wireless communications. Current mainstream platforms, typically based on programmable metasurfaces, suffer from structural complexity and high cost, which impede their large-scale deployment. Alternatively, mechanically reconfigurable metasurfaces are usually confined to switching between different modes of a fixed function, thus limiting their application scope. To overcome these limitations, a dynamic multifunctional metasurface based on a passive cascade structure is proposed. The proposed structure, consisting of two passive metasurfaces, achieves reconfigurable functionality through simple mechanical displacement, enabling switching among distinct functions such as beam steering, EM focusing, vortex beam generation, etc. The proposed method is more cost-effective than programmable metasurfaces and offers greater functional flexibility than existing mechanical reconfigurable metasurfaces. It presents a low-cost and multifunctional platform for EM wave manipulation, opening up new opportunities for future wireless systems and sixth-generation (6G) communications.

Early detection of skin cancer is significant in enhancing the process of clinical diagnosis and treatment. This is especially important in the case of basal cell carcinoma (BCC), which is the most common type of skin cancer. In this research, a surface plasmon resonance (SPR)-based biosensor for the detection of cancer-affected basal cells through the detection of changes in the refractive index (RI) is proposed. The proposed biosensor is a multilayer structure of CsF/TiO₂/Ag/CaTiO₃/BP/PEG/anti-BerEP4 based on the Kretschmann configuration. Each layer is carefully selected to enhance plasmon excitation, strengthen electric field confinement, and improve biomolecular interaction efficiency at the sensing interface. The proposed structure consists of a BP layer, which is functionalized with PEG and anti-BerEP4. PEG and anti-BerEP4 are used to create the bioselective surface. The optical properties of the proposed structure are calculated by the TMM at 633 nm. The results obtained from the proposed structure are validated by employing the FEM and FDTD simulations. The proposed multilayer structure shows a considerable change in the angle of incidence with a small change in the refractive index. From the obtained results, it is clear that the proposed SPR biosensor device has a sensitivity of 365.30 deg/RIU, a quality factor of 131.26 RIU⁻¹, a detection accuracy of 0.359 deg⁻¹, and a figure of merit of 120.12. The obtained results confirm that the proposed SPR biosensor device has a clear and stable resonant angle change with increased interaction between light and matter. Therefore, it ensures the reliability of the proposed biosensor device in detecting BCC with promising future applications.