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Verified CAS / Academic Author9 Decoded Studies

Prof. HAN Nan

School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University

Research Publications & English Decoded Briefs

Showing 9 publications
SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4412-y

Local van der Waals gaps and resonant levels enhance thermoelectric performance of lead-free GeTe

GeTe-based thermoelectric materials are promising lead-free alternatives to PbTe, but their intrinsically high Ge vacancy concentration (~10^21 cm^-3) leads to excessive carrier density and degraded Seebeck coefficient. This study integrates resonant levels (RLs) via In doping and local van der Waals gaps via Sb/Bi alloying to decouple electron and phonon transport. The optimal composition Ge0.91Sb0.04Bi0.04In0.01Te exhibits a Seebeck coefficient of ~287.31 μV K^-1 at 323 K, more than double that of the In-free sample (~102.28 μV K^-1). The peak figure of merit zT reaches ~1.8 at 723 K, with an average zT of ~1.0 over 323–723 K. Vickers hardness is enhanced to ~224 HV, a ~93% improvement over pristine GeTe (~116 HV). X-ray diffraction reveals a structural evolution toward a pseudo-cubic phase with increasing In content, and the (202) peak shifts to lower angles, indicating lattice expansion. These results demonstrate that synergistic RLs and van der Waals gaps effectively optimize carrier concentration and suppress thermal conductivity, offering a viable route for high-performance, mechanically robust GeTe thermoelectrics.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3846-9

Steering E/Z Linkage Modes in Isomeric Metal-Covalent Organic Frameworks for Photocatalytic Hydrogenation

The tuning of ligand linkage modes in porous crystalline materials to create isomers with varied properties is significant, yet remains rare in structural design and photocatalytic applications. Here, we investigate isomeric metal-covalent organic frameworks (MCOFs), MCOF-E and MCOF-Z, and reveal that specific construction struts lead to E/Z ligand linkage modes with distinct stacking structures, stimulated by temperature. These isomeric MCOFs exhibit different light absorption, charge transfer, and photocatalytic performance. Notably, MCOF-E achieves an aniline generation efficiency of 4.90 mM h−1 in nitrobenzene hydrogenation, with high conversion (~100%) and selectivity (>99%), outperforming MCOF-Z and other counterparts. Theoretical calculations indicate that MCOF-E possesses a narrower band gap than MCOF-Z, facilitating more efficient generation of photo-induced carriers, which accelerates reaction kinetics and significantly improves nitrobenzene hydrogenation efficiency. This work provides insight into the structure-function relationships of MCOFs and demonstrates the potential of isomerization as a strategy to optimize photocatalytic performance.

Chinese Journal of Environmental Engineering2026DOI: 10.12030/j.cjee.202509009

Two-Phase Flow Characteristics of a Jet Aerator with Built-in Porous Thin Plates

Air-supplied jet aerators, combining hydraulic jet and gas induction principles, are critical equipment in aerobic biological wastewater treatment. However, low energy conversion efficiency and insufficient local gas-liquid mixing are core bottlenecks limiting their competitiveness. A three-dimensional flow field analysis method for jet aerators was developed based on the k-ε turbulence model and Euler-Euler multiphase flow model. The effects of different orifice plate distributions, shapes, sizes, hole numbers, and installation positions on average pressure, turbulent kinetic energy, and turbulent dissipation rate were systematically studied. Results show that the asterisk-shaped orifice plate yields the highest gas-liquid two-phase turbulent mixing intensity, followed by the annular shape, while the parallel arrangement yields the lowest. With increasing hole number and single-hole size, average pressure, velocity, turbulent kinetic energy, and turbulent dissipation rate for different plate shapes initially fluctuate downward and then stabilize. When the number of triangular holes is 9, mass transfer efficiency is significantly enhanced, and overall aerator performance is excellent. When the triangular hole diameter is 7 mm, the device achieves an optimal match between energy utilization and mixing efficiency across pressure distribution, velocity field, turbulent kinetic energy, and dissipation rate. The farther the porous thin plate is installed from the sewage nozzle, the further gas-liquid two-phase turbulence is enhanced. Experiments confirm that the boundary layer is fully developed, liquid and air are thoroughly mixed, and the orifice plate promotes bubble breakup and refinement through throttling and collision, significantly improving oxygen transfer efficiency. This research provides a theoretical basis and technical support for the transformation and upgrading of aeration technology towards high efficiency and low carbon, and for extending equipment service life.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-4046-6

Dimensionally Extended Homochiral Metal-Organic Frameworks for Catalysis and Enantioselective Sensing

The deliberate control of framework dimensionality represents a powerful yet underexplored strategy for tailoring the functionality of homochiral metal-organic frameworks (HMOFs). Herein, we report a logical dimensional evolution from 1D and 2D to 3D HMOFs, achieved by tuning the connectivity of the auxiliary ligand. Employing a planar, three-connected ligand, 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (Tpt), together with enantiopure tetracarboxylate of cyclohexane diamide linkers ((1R,2R/1S,2S)-cyclohexane-1,2-dicarbonyl bis(azanediyl)diisophthalate) (R,R/S,S-CHCAIP) and Zn2+ salts, a pair of 3D porous HMOFs (P/M-HMOF-5) was successfully constructed. The 3D framework features unique heart-shaped channels and a novel 4-(3,3,3,6)-connected topology. Structural analyses reveal trinuclear Zn3(μ3-O) clusters that, upon activation, generate open metal sites. These Lewis acid sites, synergizing with Lewis basic sites from the framework, confer efficient acid-base bifunctional heterogeneous catalysis for the synthesis of 2,3-dihydroquinazolinones in excellent yields (90%–98%). Furthermore, P/M-HMOF-5 serve as highly sensitive and enantioselective fluorescent sensors for amino acids and α-hydroxy carboxylic acids, with the highest discrimination observed for phenylalanine (KBH(D-Phe)/KBH(L-Phe) = 5.85 for M-HMOF-5). This work demonstrates how rational ligand connectivity steers dimensional evolution, enabling the integration of distinct catalytic and sensing functions within a single chiral platform, thereby providing a blueprint for the design of advanced multifunctional materials.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3806-0

A dual enzyme-mimicking COF sonosensitizer potentiates cancer sonodynamic therapy via cascade oxygenation and ROS storm

Sonodynamic therapy (SDT) faces critical limitations from inefficient sonosensitizers and the hypoxic tumor microenvironment, which curtail reactive oxygen species (ROS) generation. Here, we report a dual enzyme-mimicking sonosensitizer, termed sonozyme, engineered by integrating platinum nanoparticles (Pt NPs) with a tailored covalent organic framework (Y-COF). The spatially separated donor-acceptor architecture optimizes the band position of Y-COF, conferring intrinsic sonodynamic activity. Pt NPs further enhance ultrasound-triggered ROS generation by promoting exciton separation and transfer. Notably, sonozyme exhibits catalase (CAT) and peroxidase (POD) mimetic activities, converting endogenous H2O2 into O2 and ·OH, thereby alleviating hypoxia and augmenting oxidative stress. In vitro assays demonstrated significantly enhanced ROS production and cancer cell death under ultrasound irradiation. In vivo studies confirmed that sonozyme effectively suppresses tumor progression without observable systemic toxicity. This work presents a paradigm for designing high-performance multifunctional sonosensitizers, offering a promising strategy for cancer therapy.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3976-x

Entropy stabilization and effect of A-site ionic size in bilayer nickelates

The discovery of high-temperature superconductivity in bilayer nickelate La3Ni2O7−δ (La-327) under high pressure and in thin films at ambient pressure has opened new avenues in superconductivity research. However, La-327 exhibits a narrow phase stability range, leading to stacking faults that suppress bulk superconductivity. Chemical substitutions, particularly at the A-site with smaller rare-earth ions, have been shown to enhance phase purity and reduce stacking faults, while also increasing the orthorhombic distortion and chemical pressure. In this work, we apply the high-entropy (HE) strategy to stabilize the 327 phase with reduced average A-site ionic radius (rA). We successfully synthesized medium-entropy La1.2Pr0.6Nd0.6Sm0.6Ni2O7−δ (ME-327) and high-entropy La0.67Pr0.67Nd0.67Sm0.33Eu0.33Gd0.33Ni2O7−δ (HE-327) polycrystalline samples. These compositions satisfy medium- and high-entropy criteria, with rA values of 1.181 Å and 1.164 Å, respectively. The samples are phase-pure and homogeneous. HE-327 exhibits the lowest cell volume, largest orthorhombicity, and shortest interlayer Ni-Ni distance among reported bilayer nickelates. Physical property measurements reveal low electrical conductivity and a high density-wave (DW) transition temperature. Under high pressure, HE-327 shows a resistivity anomaly at 103 K under 31 GPa, suggesting a possible superconducting transition. Extrapolation indicates that Tc under high pressure exceeds 100 K for HE-327, correlating with reduced rA and enhanced interlayer coupling. Our results demonstrate the ionic size effect and the effectiveness of the HE approach in stabilizing bilayer nickelates, providing a new avenue for developing superconducting materials.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3765-9

Charge Homogeneity Redefines Ion Selectivity in Polyamide Membranes

Ion-selective membranes are critical for water purification, resource recovery, and energy storage. Polyamide (PA) nanofiltration (NF) membranes are the gold standard, with size sieving and charge repulsion as fundamental mechanisms. However, the role of surface charge distribution has been overlooked. A groundbreaking study in Nature Water reveals that nanoscale spatial charge homogeneity, not pore size distribution, is the key determinant of ion selectivity. Using multimodal atomic force microscopy (AFM) techniques, including Kelvin probe force microscopy (KPFM) and electrostatic force microscopy (EFM), the authors mapped surface charge of commercial NF270 and NF90 membranes. NF270, despite looser pores, exhibited a Cl−/SO4^2− selectivity nearly tenfold higher than NF90, correlating with a more homogeneous charge distribution. AFM-infrared spectroscopy (AFM-IR) showed uniform carboxyl group (–COOH) distribution on NF270, while NF90 had patchy, structure-dependent distribution, creating defects for ion leakage. Molecular dynamics simulations confirmed SO4^2− ions preferentially localize in regions lacking –COOH. The authors translated this insight into a polyethyleneimine multivariate (PEI-MTV) strategy to program homogeneous positive charge on PA membranes for cation separation. Comparing grafting routes, EDC/NHS-catalyzed amidation yielded the most homogeneous charge distribution and highest charge density, achieving exceptional Li+/Mg2+ separation performance. This work establishes a transformative design principle for highly selective membranes via nano-charge manipulation, bypassing precise pore size control.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3921-2

Aligned Ion Transport Design Advances High-Performance Moisture-Enabled Energy Harvesting and Multidirectional Sensing

Moisture-enabled energy harvesting technologies offer a promising route for self-powered strain sensing, yet conventional generators suffer from slow response, poor recovery, and limited multidirectional resolution. Here, we report a stretchable thermoplastic polyurethane (TPU) nanofiber moisture-enabled electric generator (MEG) with highly aligned ion channels. A carbon black/sodium dodecylbenzene sulfonate (CB/SDBS) layer is coated on the TPU membrane, while carboxymethyl cellulose (CMC) and acidified poly(sodium 4-styrenesulfonate) (HPSS) are applied on opposite sides, establishing lateral hydrophilicity and ion gradients to drive directional ion migration. The planar MEG is lightweight, flexible, and requires no fully covered electrodes, enabling conformity to complex deformations. The aligned channels reduce ion migration tortuosity, enhancing ion transport efficiency and flux. As a result, the aligned MEG (ATMEG) delivers 0.2 V and 0.51 μA cm−2 at ~90% relative humidity, corresponding to 400% and 287% enhancements compared with the unaligned MEG (UATMEG). The ATMEG also exhibits ultrafast response (0.16 s) and recovery (0.08 s). Utilizing its anisotropic characteristics, a multidirectional self-powered strain sensor is developed, capable of distinguishing both the amplitude and direction of human motion, demonstrating strong potential for adaptive wearable electronics and intelligent motion monitoring.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3997-9

An Event-Driven Sensor Based on Colloidal Quantum Dots for Contactless Human-Machine Interaction

Contactless human-machine interaction (HMI) is rapidly evolving, yet it remains constrained by the latency, redundancy, and power consumption inherent in conventional frame-based vision sensors. While bio-inspired event-driven sensors offer a low-power alternative, existing architectures are often complex or fail to accurately encode the magnitude of light intensity changes. Herein, we report a solution-processed, two-terminal event-driven sensory device based on CuIn(Se,S)2 colloidal quantum dots (QDs) integrated with an Sb-doped TiO2 layer. Unlike traditional dynamic vision sensors (DVS), this device exhibits a transient photoresponse that encodes both the polarity and the magnitude of light intensity variations into the output current amplitude. This preservation of magnitude information significantly enhances the feature extraction capability, leading to faster convergence and superior clustering performance in gesture recognition. Based on these unique optoelectronic properties, we constructed a hierarchical HMI system that synergizes the strengths of event-based and frame-based sensing. The system utilizes the event-driven sensor for low-latency gesture control of an unmanned aerial vehicle (UAV) and a frame-based sensor for high-precision gaze control of an unmanned ground vehicle (UGV). The proposed system achieves a gesture recognition accuracy of more than 92.5% while substantially reducing data redundancy, offering a promising strategy for efficient, robust, and low-cost intelligent interaction systems.