SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3897-6
Decoding the nature of catalytically active sites is an essential prerequisite for the rational design of catalysts for electrochemical H2O2 synthesis, but faces significant challenges, particularly for controversial cobalt single-atom catalysts (Co SACs). Herein, we report trace Co single-atom sites embedded within pyridinic N-rich carbon nanospheres (Co1-NNH3-C), synthesized via a self-assembly coupled surface-coating strategy. The Co1-NNH3-C catalyst demonstrates remarkable H2O2 selectivity (99%) and activity at current density of −3.5 mA cm−2 in 0.1 M H2SO4. Through a combined approach of molecular probe experiments, surface modification, and density functional theory (DFT) calculations, we disclose that pyridinic N, rather than Co single atoms, serves as the direct active site for 2e− oxygen reduction reaction (ORR). The trace Co (0.05 wt%) indirectly facilitated pyridinic N formation during pyrolysis but exhibits negligible direct catalytic involvement. DFT reveals pyridinic N sites optimize OOH intermediate adsorption (ΔG*OOH = 4.0 eV) and minimize reaction overpotential of 0.20 V, enabling scalable H2O2 production (907.5 mmol gcat−1 h−1). This work redefines the role of trace metal in SACs, providing a paradigm for designing metal-induced carbon catalysts for sustainable electrosynthesis for H2O2.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3995-6
The deployment of single-site metal catalytic nodes into zirconium-based metal-organic frameworks (Zr-MOFs) offers vast advantages in catalytic recyclability, product separation, and mechanistic analysis, underscoring their paramount significance in heterogeneous catalysis. Nonetheless, their occupation within pores/channels usually diminishes mass transfer and catalytic efficiency during reactions such as the hydroboration of carbonyl compounds, especially for bulkier substrates. To address this issue, three microporous single-site Ti(IV) embedded Zr-MOFs with sequentially extended ligand arms are novelly synthesized to enable precise pore modulation ranging from 9.04, 10.12, to 11.18 Å. The catalytic performance is investigated using eight carbonyl compounds of varying sizes and four additional larger-scale substrates, which demonstrates that the catalytic efficiency is increased through pore size regulation, yet still away from optimal catalytic performance. Then a further strategy was shifted to the linker installation of linear dicarboxylate ligands chelated single-site Ti(IV) within coordination-unsaturated windows of mesoporous Zr-MOFs, and the result elucidates that the obtained catalyst exhibits superior catalytic efficiency (all exceeding 90%) while preserving the inherent mesoporosity of Zr-MOFs with a pore size of approximately 21.73 Å. We believe this research provides critical guidance for future research on structural design and catalytic optimization of MOFs, opening new avenues in heterogeneous catalysis.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3955-0
Nickel-rich layered cathodes (Ni≥80%) offer high discharge capacity for lithium-ion batteries but face sustainability and structural stability challenges. This study presents a radially multiphase integrated low-nickel (Ni<60%) cathode material, Li(Li0.05Ni0.57Mn0.31Co0.07)O2 (LNC), which achieves high capacity and long-term cycling stability by leveraging highly reversible anionic redox chemistry. The cathode comprises three distinct radial phases: an outermost epitaxial rock-salt phase with lithium-percolation channels, an intermediate lithium-rich manganese-rich phase with delocalized superlattice ordering, and an inner nickel-rich layered phase. The rock-salt phase suppresses interfacial side reactions and structural degradation, while the superlattice enhances lattice oxygen redox reversibility, as evidenced by resonant inelastic X-ray scattering (mRIXS) showing persistent spectral features at 4.5 V even after 100 cycles. The inner nickel-rich phase provides high discharge capacity via nickel-ion redox. This synergistic integration minimizes lattice variations and nickel oxidation state changes during cycling, as demonstrated by in-situ high-energy X-ray diffraction. Compared to commercial N60, N70, N80, and N90 cathodes, LNC delivers superior discharge capacity, cycling stability, and rate performance while reducing nickel dependence, offering a sustainable pathway for high-energy-density batteries.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4132-y
Manganese-iron-based mixed polyanionic cathodes are promising for sodium-ion batteries (SIBs) due to high energy density and operating voltage, but suffer from Jahn-Teller distortion of Mn3+ that degrades cycling stability. Here, a structural modulation strategy via Mg2+ doping is reported. Electrochemically inert Mg2+ forms stronger chemical bonds, adjusts lattice parameters, and suppresses Jahn-Teller distortion, enhancing structural stability. Mg2+ also widens sodium-ion diffusion channels, improving diffusion kinetics. Additionally, an in-situ three-dimensional carbon nanotube (CNT) conductive network boosts electronic conductivity. The resulting NFMPP-Mg@CNTs cathode delivers a discharge capacity of 126 mAh g−1 at 0.1 C (near theoretical 129 mAh g−1), retains 80% capacity after 3000 cycles at 0.5 C, and achieves an energy density of 401 Wh kg−1, among the highest reported for mixed phosphate systems. Ex-situ XPS and first-principles calculations confirm that Mg2+ resists geometric distortion by enhancing lattice stability and widening Na+ diffusion pathways (migration barrier reduced from 0.566 to 0.398 eV). This work provides a viable route for high-energy, long-life SIB cathodes suitable for large-scale energy storage.