Min Wang

Earth‐abundant Cu and Co are attractive electrocatalysts for nitrate reduction to ammonia (NO ₃ ⁻ RR); however, conventional solid‐solution alloys with single‐phase active sites lack effective intermediate spillover, impeding the hydrogenation of multiple reaction intermediates and limiting NH ₃ selectivity under dilute nitrate conditions. Here we report phase‐separated yet electronically coupled Janus–CuCo alloys synthesized via a time–charge regulated electrochemical reduction strategy, forming metallic Cu/Co domains with a well‐defined interphase electronic structure. This Janus architecture enables relay catalysis, in which Cu domains activate NO ₃ ⁻ , intermediates migrate to Cu−Co interfaces for hydrogenation, and adjacent Co domains promote subsequent NH ₃ formation. In situ characterizations reveal pronounced Cu–Co synergy, where Co sites regulate *H‐mediated hydrogenation while the balanced surface coverage of *H and *NO ₃ ⁻ optimizes NH ₃ selectivity and yield. Consequently, the optimized Janus Cu−Co catalyst, Janus–Cu ₇₀ Co ₃₀ /NOMC, achieves a peak NH ₃ Faradaic efficiency (FE _NH3 ) of 95.5% at −500 mA cm ⁻² and delivers a FE _NH3 of 93.1% with an NH ₃ yield rate of 4.2 mg h ⁻¹ mg _cat ⁻¹ at −0.4 V vs RHE in an MEA flow cell under low nitrate concentrations. These findings establish phase separation with electronic coupling, enabled by electrochemical time–charge control, as an effective design principle for efficient multistep NO ₃ ⁻ RR electrocatalysis.

The oxygen reduction reaction (ORR) remains a central kinetic bottleneck in fuel cells. Its performance depends not only on catalyst activity, but also on electron/proton transfer, oxygen transport, and surface reaction kinetics. Because catalytic reactions and mass transport occur on different timescales, their matching is essential for efficient ORR. Covalent organic frameworks (COFs) have attracted increasing interest in ORR electrocatalysis because of their tunable structures and ordered pores. However, current studies mainly focus on material classification or activity regulation, while the relationship between transport and reaction kinetics remains insufficiently understood. To bridge this gap, this review proposes a transport‐reaction coupling framework for COF‐based ORR electrocatalysts. By comparing pyrolyzed and non‐pyrolyzed COFs, a key principle is revealed: electron, proton, and oxygen transport should be balanced with regulation of the local reaction environment. This review links molecular COF design, multiscale transport, and device performance to guide the design of COF‐based ORR electrocatalysts.

The accelerating global “dual‐carbon” transition and the rapid proliferation of electric vehicles are driving an unprecedented surge in spent lithium‐ion batteries (LIBs), with the first major retirement peak expected around 2030. Cathode materials form a pivotal bridge between urban mining and green‐hydrogen technologies, coupling environmental risks with the strategic importance of critical metals. This review delivers a comprehensive overview of the recycling and upcycling landscape for the three dominant cathode families—LiCoO ₂ , LiNi _x Co _y Mn _1‐x‐y O ₂ , and LiFePO ₄ . We outline the compositional and structural features of these materials, evaluate pretreatment protocols, and critically compare pyrometallurgical, hydrometallurgical, and direct‐regeneration strategies. We then highlight how multiscale structure–activity correlations guide the transformation of regenerated cathodes into high‐performance electrocatalysts, with emphasis on defect engineering, electronic‐structure modulation, interfacial coupling, and the assembly of conductive networks to accelerate both hydrogen‐ and oxygen‐evolution pathways. Finally, we propose a forward‐looking design framework that integrates atomic‐site dynamics, multimetallic synergy, and process‐environment co‐optimization, while underscoring emerging opportunities in machine‐learning‐guided inverse design, operando mechanistic mapping, and device‐level implementation. This review provides a conceptual blueprint for integrating battery recycling with green‐hydrogen production in a closed‐loop materials ecosystem.

A novel cucumber pulp certified reference material (CRM) was prepared for the analysis of plant growth regulator residues, specifically chlormequat chloride (CCC) and 2,4-dichlorophenoxyacetic acid (2,4-D). The matrix CRM candidates were prepared by cucumber pulping, spiking, homogenizing and subpackaging. A reference method of liquid chromatography tandem isotope dilution mass spectrometry (ID-LC-MS/MS) was established for simultaneous measurement of mass fractions of CCC and 2,4-D in cucumber pulp. Interlaboratory value assignment of CCC and 2,4-D in the cucumber pulp CRM was performed using the ID-LC-MS/MS method. The certified values with expanded uncertainties (coverage factor k = 2) were assigned to be 4.1 mg/kg ± 0.4 mg/kg for CCC, 2.0 mg/kg ± 0.2 mg/kg for 2,4-D. Homogeneity assessment was performed on fifteen randomly selected units, and statistical analysis confirmed the CRM’s homogeneity for both CCC and 2,4-D, both between and within packages. The long-term stability of the CRM at −20 °C storage condition and short-term stability at 30 °C were monitored for 14 months and nine days, respectively, and no significant trend differences were observed. The uncertainty contributions from characterization, homogeneity and stability were taken into account in uncertainty evaluation. The CRM was officially certified and registered under the number GBW(E)100932 by the State Administration for Market Regulation of the P. R. China.

By integrating material selection with structural design, tailored approaches can be applied to specific components to realize internal self-humidification functionality.

The formation of porosity within nanoparticles via dealloying is notably constrained by the dimensions of the precursor particles, a limitation stemming from the surface kinetic processes occurring during dealloying. In this study, we present a straightforward methodology, specifically tailored for fabricating diminutive nanoporous alloy nanoparticles, originating from their small-sized precursor counterparts. We initiated our research with precursor PtNi alloy nanoparticles, which possess an average diameter of 9 nm. By incorporating an extrinsic metal, Ir, known for its slower surface diffusion on the nanoparticle surface, we successfully modulated the surface migration velocity of Pt during the dealloying process of the PtNi alloy nanoparticles. This precise manipulation led to the formation of an abundantly complex nanoporous structure on diminutive PtNi nanoparticles. Owing to their enhanced high surface area-to-volume ratio and the synergistic alloy effect, electrochemical tests revealed that the Ir-coated diminutive nanoporous PtNi nanoparticles exhibit superior electrocatalytic activities towards oxygen reduction and formic acid oxidation reactions. Furthermore, the presence of Ir on the surface effectively suppresses the surface diffusion rate of Pt, thereby significantly inhibiting the coarsening evolution of the porous metallic structure. This intervention ensures the long-term preservation of both structural integrity and catalytic stability.