The photoelectrochemical (PEC) synthesis of hydrogen peroxide (H2O2) on hematite (Fe2O3) is plagued by issues such as poor electrical conductivity and short hole diffusion length, which can result in severe recombination of electron-hole pairs, thereby limiting both the H2O2 yield and Faraday efficiency. To overcome these limitations, this study utilizes the synergistic effect of Ge/Ti in Fe2O3 and constructs a nanoporous Fe2O3 structure via the Kirkendall effect. Through density functional theory (DFT) calculations, sample morphological analysis, and electrochemical analysis, Ti doping plays a critical role in accelerating Fe atom diffusion by regulating oxygen vacancies and improving charge transfer, enabling the Kirkendall effect between Fe in the Ti:FeOOH layer and Ge in the surface GeO2 layer during high-temperature annealing. This process generates internal voids that coalesce into a nanoporous morphology, effectively shortening the hole diffusion length of Fe2O3, thereby inhibiting charge recombination and boosting water oxidation kinetics. The optimized Ge/Ti:Fe2O3 photoanode achieves a H2O2 yield of 0.488 mu mol min- 1 cm- 2 at 1.4 versus the reversible hydrogen electrode (vs. RHE), with a remarkable Faradaic efficiency of 85.6% for the 2-electron WOR. This work presents a promising strategy to address the intrinsically low PEC activity of hematite photoanodes.

Self-assembled InAs quantum dots (QDs) are promising for optoelectronic applications due to their tunable bandgap and quantum confinement. However, overgrowth often causes inhomogeneity and degradation. This study systematically investigates GaAs, InGaAs, and AlGaAs capping layers for InAs/GaAs quantum dots using HRXRD, AFM, and PL spectroscopy. Structural and optical properties are characterized using X-ray diffraction, photoluminescence spectroscopy, and electron microscopy. The InGaAs layer is found to improve size uniformity and cause a 59 nm redshift via strain buffering. The AlGaAs layer yields the largest QDs, a 79 nm redshift, enhanced thermal stability, and stronger carrier confinement. These results highlight the critical role of capping layers in tuning QD properties for device applications.

The catalytic dehydrogenation of propane, a critical process, is conventionally hampered by the high energy demands of the direct route and the poor selectivity associated with oxidative dehydrogenation using molecular oxygen. This work presents a strategic synthesis of Zr and Co co-doped CeO2 nanorods, fabricated through a combination of hydrothermal and atomization-drying techniques, for application in photothermal CO2-mediated oxidative dehydrogenation of propane (CO2-ODHP). The optimized Co/Zr-CeO2 catalyst exhibits markedly enhanced performance under low-temperature illumination, delivering a high propane conversion of 230.04 mu mol & sdot;gcat-1 while maintaining 90.3 % selectivity toward propylene. Comprehensive characterization and analysis reveal that the co-doping strategy simultaneously introduces abundant oxygen vacancies and electronically modifies the CeO2 host. The resultant tailored band structure promotes the separation and utilization of photogenerated carriers under light irradiation, which synergizes with the defect-mediated thermal catalysis to drive the efficient dehydrogenation of propane. This study highlights the effectiveness of coupled structural and electronic engineering in developing high-performance photothermal catalysts for alkane valorization.

A series of InAs/GaAs submonolayer quantum dot (SML-QD) structures was fabricated using molecular beam epitaxy (MBE). These structures were systematically characterized using atomic force microscopy (AFM), high-resolution x-ray diffraction (HRXRD), and photoluminescence (PL) spectroscopy. This study examined the effect of the InAs growth rate on the surface morphology, structural strain, and photoluminescence properties of SML-QDs. Results indicate that adjusting the growth rate effectively modulates the surface morphology and optical properties of InAs/GaAs SML-QDs. At a growth rate of 0.03 Ml s-1, AFM images revealed a step-flow growth mode. HRXRD analysis indicated minimal strain and no evidence of relaxation, suggesting optimal crystal quality under this condition. Temperature-dependent PL measurements confirmed that the optical bandgap of this sample obeyed the Varshni equation, demonstrating excellent thermal stability. Furthermore, fitting the temperature-dependent PL data with the Arrhenius equation yielded the highest carrier activation energy for this sample, indicating its exceptional capability to suppress thermal carrier escape and non-radiative recombination. In summary, optimizing the growth rate enables the controlled preparation of high-performance InAs/GaAs SML-QDs, demonstrating significant application potential in optoelectronic devices.

In this study, a series of NiFeCr layered double hydroxide (NiFeCr-LDH) materials with sheet-like morphology and different electronic structure distributions were synthesized via a facile one-step hydrothermal method by adjusting the elemental ratios. As a reliable and stable electrocatalyst, this trimetallic material exhibits prominent advantages in enhancing the kinetics of the oxygen evolution reaction (OER). Under identical catalyst loading, the NiFeCr-3 sample with an Fe : Cr molar ratio of 5 : 3 demonstrated the optimal electrocatalytic performance. This improvement was primarily attributed to the formation of highly active NiOOH species during the catalytic process, while the abundant charge-transfer pathways and variable ionic valence states further contributed to its intrinsic OER activity. In alkaline electrolyte tests, the overpotentials required to achieve current densities of 50 mA cm-2 and 100 mA cm-2 were only 287 mV and 331 mV, respectively, with a Tafel slope of 86.5 mV dec-1. Furthermore, the catalyst exhibited excellent long-term stability, maintaining its activity for over 100 hours at a current density of 20 mA cm-2. Electrochemical measurements and X-ray photoelectron spectroscopy analysis collectively confirmed the synergistic effects among the metal centers in NiFeCr-LDHs. Its catalytic activity was significantly higher than that of NiFe-LDH, indicating the potential of this work for developing high-performance water-alkali electrocatalysts.

Submonolayer quantum dots (SML-QDs) have emerged as promising candidates for high-performance optoelectronic devices due to their ability to suppress wetting layer formation and enhance carrier confinement. This work systematically investigates the critical influence of growth temperature (470-490 degrees C) on the structural evolution and optical properties of InAs/GaAs SML-QDs grown by molecular beam epitaxy (MBE). Atomic force microscopy (AFM) reveals that elevated temperatures enhance indium adatom mobility, promoting a transition from island-like to step-flow growth and significantly reducing surface roughness from 0.186 nm to 0.115 nm. However, high-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) analyses indicate that excessively high temperatures (490 degrees C) intensify In-Ga interdiffusion, resulting in reduced indium content within the SML region and the formation of a parasitic InGaAs alloy layer, which manifests as a high-energy secondary emission peak. The sample grown at 480 degrees C exhibits the optimal trade-off, demonstrating the strongest intrinsic SML-QDs luminescence, and a maximum thermal activation energy of 100.45 meV, indicative of superior crystal quality and strong carrier confinement. These findings elucidate the competitive mechanism between surface mobility and interfacial alloying, identifying 480 degrees C as the optimal growth window for fabricating high-quality SML-QDs

Two-dimensional layered MoS2 has been considered the most promising anode material for potassium-ion batteries (PIBs) due to its relatively large interlayer spacing and high theoretical specific capacity. Despite extensive research on their electrochemical performance, reaction mechanisms, structural changes, and kinetic behavior during potassiation processes are still unknown or controversial. Here, in situ transmission electron microscopy was used to track the migration of potassium ions in the layered structure of MoS2 nanosheets in real time at the atomic scale. These results reveal that the potassiation process proceeds in a region-by-region manner, namely, a multistep intercalation reaction initiated from the outer region to the adjacent inner region. Meanwhile, the local stress induced by the insertion of potassium ions results in structural distortion, deformation, and dislocation formation. Additionally, the potassiation behaviors of MoS2 nanosheets only involve intercalation, and the final product is identified as KxMoS2, which is quite different from the mechanisms of lithiation and sodiation. Meanwhile, density functional theory calculations verified that less electrovalent K-S bonds inhibit the occurrence of the conversion reaction, favoring maintenance of the MoS2 layered structure. This work provides valuable insights into the potassiation mechanisms of MoS2 and guides the design of high-performance anodes for PIBs.

M-N-C single-atom catalysts have been demonstrated to be a promising class of non-noble-metal based catalysts, but their activity is largely constrained by the symmetrical electronic density distribution of the M-N4 moieties. Herein, a ZIF-8 derived Fe/Fe dual-center catalyst (FeN4/FeO5@NC) is constructed by introducing a O-FeO4 configuration adjacent to the Fe-N4 sites to form asymmetric dumbbell-shaped FeN4-O-FeO4 active sites, resulting in improved intrinsic activity of Fe─N─C catalyst. The dumbbell FeN4-O-FeO4 dual-center catalyst features an electron transfer pathway of "FeN4 → bridged O → FeO4", which breaks the symmetry of the electronic density distribution of the Fe moiety and regulates the position of the d-band center, increasing the electron transfer efficiency, reducing the desorption energy barrier of the rate-determining step, and enhancing the activation ability of O2 molecules. The obtained FeN4-O-FeO4 dual-center catalyst exhibits excellent ORR performance in a pH-universal range. The liquid-state Zn-air battery (ZAB) with this FeN4-O-FeO4 dual-center catalyst delivers an outstanding open circuit voltage of 1.502 V and a peak power density of 246 mW cm-2, superior to the Pt/C-cathode ZAB. This work represents an exploration of ways to improve the ORR performance of Fe─N─C catalysts and provides a paradigm for rationally designing low-cost, highly catalytic, and stable non-noble metal catalysts.

Achieving high solar-to-chemical conversion (SCC) efficiency is imperative for the practical application of semiconductors photocatalytic H2O2 production. However, this objective remains significantly challenging due to limitations inherent in conventional systems, including inefficient light harvesting, rapid charge recombination, and mass transfer constraints. To address these bottlenecks, a synergistic "material-system" design is validated. At the material level, ultraviolet-visible, X-ray photoelectron spectroscopy, and time-resolved photoluminescence analyses confirm that the S-pCN/BiVO4 S-scheme heterojunction significantly broadens visible light absorption and facilitates directed charge separation. At the system level, contact angle and kinetic analyses demonstrate that anchoring the catalyst onto a hydrophilic polyurethane-poly (propylene glycol) (HPU-PGG) hydrogel creates a floatable platform with a three-phase interface, enabling direct atmospheric oxygen utilization and superior mass transfer. Furthermore, the system's physical architecture effectively isolates the photocatalyst from the H2O2 product, suppressing undesirable decomposition. Consequently, the S-pCN/BiVO4/HPU-PGG system achieves a high H2O2 yield of 488μmol/L/h under visible light irradiation. This synergistic design achieves an SCC efficiency of 0.85%, which is eight times higher than that of natural photosynthesis.

InGaN multiple quantum wells (MQWs) operating in the ultraviolet A spectral band face significant challenges in achieving high quantum efficiency due to the pronounced quantum-confined Stark effect (QCSE) and the difficulty of incorporating In at low In compositions. This work employs a dual strategy of optimizing ultra-thin QW structures and incorporating GaN interlayers to enhance the quantum efficiency of InGaN/GaN heterostructures. The synergistic interplay between the quantum confinement effect and interfacial strain effectively reduces the density of non-radiative recombination centers and mitigates the detrimental impact of the QCSE. Combining electron energy loss spectroscopy with first-principles calculations, we have characterized the local charge reconstruction at the heterointerfaces. This characterization unequivocally confirms the regulatory role of QW interfaces with different thicknesses in modulating the built-in electric field. Our findings provide a novel research paradigm for a more in-depth exploration of the mechanisms governing interface and defect behavior in semiconductor heterostructures.

ABSTRACT The electrochemical CO 2 reduction reaction (CO 2 RR) to ethylene (C 2 H 4 ) is an ideal pathway for closing the carbon cycle. However, single Cu‐based catalysts often have an insufficient supply of CO intermediates and restricted C‐C coupling kinetics, which collectively constrain the C 2 H 4 production efficiency. Additionally, the fabrication of traditional single‐Cu‐based catalyst electrodes typically involves the use of polymer binders to enhance adhesion; however, this often results in high interfacial resistance and impedes mass transport. To address these challenges, this study presents a binder‐free AgNPs/CuNWs tandem catalyst strategy using a gas diffusion electrode (GDE). The uniformly dispersed silver nanoparticles (AgNPs) efficiently generate CO intermediates, providing high concentrations, while the adjacent copper nanowires (CuNWs) act as C‐C coupling sites, reducing the locally generated CO into C 2 H 4 . Electrochemical tests demonstrate that this tandem catalyst exhibits superior catalytic performance, achieving a C 2 H 4 Faradaic efficiency (FE) of 43% at ‐1.2 V (vs. RHE). Furthermore, the catalyst maintained excellent structural integrity and catalytic activity during a 24‐hour stability test. Comparative CO reduction reaction (CORR) experiments confirmed that the AgNPs/CuNWs system follows a tandem catalytic mechanism. This work provides new insights into designing efficient, stable, and binder‐free electrocatalysts for C 2 H 4 production.

In NiP-based catalysts, although Ni2 P and Ni5 P4 have relatively high catalytic activity, the catalytic performance of single-phase Ni2 P or Ni5 P4 is still far from that of noble metal catalysts. The dual-phase heterojunction has better catalytic performance than single-phase materials due to its faster interface charge transfer rate and more active sites. The Ni2 P/Ni5 P4 @CC heterostructural catalyst with oriented porous nanosheet arrays grown on carbon cloth (CC), was in-situ constructed through the controllable phase transition of Ni2 P. By modulating the amount of P source (P-dependent) or the phosphating reaction time (Time-dependent), the degree of the Ni2 P phase transition could be modulated, thus obtaining the Ni2 P/Ni5 P4 @CC heterostructural catalyst with the required component ratio of Ni2 P and Ni5 P4 . When the ratio of Ni2 P and Ni5 P4 was 15.7:84.3, the Ni2 P/Ni5 P4 @CC catalyst had the best catalytic performance. Its hydrogen evolution reaction (HER) overpotentials were only 139 and 87 mV overpotentials reaching -10 mA/cm2 in 1 mol/L KOH and 0.5 mol/L H2 SO4 , respectively, which was much lower than that of the single-phase Ni2 P@CC (base: 278 mV; acid: 123 mV) and Ni5 P4 @CC (base: 166 mV; acid: 106 mV) catalysts. Specially, in acidic electrolyte, HER overpotential at a higher current density of -100 mA/cm2 of the Ni2 P/Ni5 P4 @CC catalyst was 270 mV, which was even lower than that of the Pt/C catalyst (328 mV), indicating that the Ni2 P/Ni5 P4 @CC heterostructural catalysts had promising prospects for commercial applications. The mechanism of catalytic performance enhancement was investigated by the density functional theory (DFT) calculations. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

The heterogeneous integration of lead-free metal halides with wide-bandgap semiconductors offers a highly promising route for the development of high-performance ultraviolet photodetectors. In this work, porous GaN was first prepared by a high-temperature annealing method, and CsCu2I3 was subsequently deposited by an antisolvent-assisted spin-coating method to construct a CsCu2I3/porous GaN heterojunction. Compared with the planar heterojunction, CsCu2I3 in the CsCu2I3/porous GaN heterojunction can partially penetrate into the pores of porous GaN, resulting in more intimate interfacial contact and a larger effective contact area. Compared with the planar heterojunction, the CsCu2I3/porous GaN heterojunction shows stronger XRD peaks and Raman signals, together with smaller FWHM values, suggesting slightly improved structural quality. Meanwhile, UV–Vis spectra show enhanced ultraviolet absorption, which may be associated with the porous GaN-induced increase in the effective optical path and improved optical utilization. Under 365 nm ultraviolet illumination at 0 V bias, the CsCu2I3/porous GaN heterojunction ultraviolet photodetector exhibits a light-to-dark current ratio of 7.3 × 104, a responsivity (R) of 0.162 A/W, a detectivity (D*) of 1.04 × 1013 Jones, an external quantum efficiency (EQE) of 55%, and a response time of 64 ms/75 ms. This work provides a feasible interface-engineering strategy for developing high-performance lead-free heterojunction ultraviolet photodetectors.

In NiP-based catalysts,although Ni2P and Ni5P4 have relatively high catalytic activity,the catalytic per-formance of single-phase Ni2P or Ni5P4 is still far from that of noble metal catalysts.The dual-phase heterojunction has better catalytic performance than single-phase materials due to its faster interface charge transfer rate and more active sites.The Ni2P/Ni5P4@CC heterostructural catalyst with oriented porous nanosheet arrays grown on carbon cloth(CC),was in-situ constructed through the controllable phase transition of Ni2P.By modulating the amount of P source(P-dependent)or the phosphating reac-tion time(Time-dependent),the degree of the Ni2P phase transition could be modulated,thus obtaining the Ni2P/Ni5P4@CC heterostructural catalyst with the required component ratio of Ni2P and Ni5P4.When the ratio of Ni2P and Ni5P4 was 15.7∶84.3,the Ni2P/Ni5P4@CC catalyst had the best catalytic performance.Its hydrogen evolution reaction(HER)overpotentials were only 139 and 87 mV overpotentials reaching-10 mA/cm2 in 1 mol/L KOH and 0.5 mol/L H2SO4,respectively,which was much lower than that of the single-phase Ni2P@CC(base:278 mV;acid:123 mV)and Ni5P4@CC(base:166 mV;acid:106 mV)cata-lysts.Specially,in acidic electrolyte,HER overpotential at a higher current density of-100 mA/cm2 of the Ni2P/Ni5P4@CC catalyst was 270 mV,which was even lower than that of the Pt/C catalyst(328 mV),indi-cating that the Ni2P/Ni5P4@CC heterostructural catalysts had promising prospects for commercial applica-tions.The mechanism of catalytic performance enhancement was investigated by the density functional theory(DFT)calculations.

The effect of an asymmetric potential barrier, engineered by selectively removing a GaAs interlayer at the downstream side of carrier diffusion in InGaAs/AlGaAs multiple quantum wells (MQWs), is investigated. The structures are grown by molecular beam epitaxy (MBE) and characterized by high-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) spectroscopy. HRXRD analysis reveals that the asymmetric barrier enhances indium interdiffusion and increases the dislocation density. However, the PL results demonstrate a significant enhancement in the emission intensity for the asymmetric structure. This improvement is attributed to superior carrier confinement, achieved by the higher potential barrier on the downstream side, which effectively reduces carrier escape. It is concluded that the strategic formation of an asymmetric barrier via interlayer removal provides a viable approach for boosting the luminescence efficiency of MQWs, in which the gain from improved carrier confinement outweighs the detrimental effects of slightly degraded crystal quality.

A three-dimensional rose-like micro-nano structured NiMnP/Ni2P/MnP4 multiphase heterogeneous architecture was fabricated on nickel foam via hydrothermal and phosphorization processes. The 3D micro-nano structure conferred the catalyst with excellent hydrophilicity, facilitating electrolyte penetration on its surface and thereby enhancing charge and reaction medium transport. The multiphase heterogeneous structure provided abundant heterogeneous interfaces, thereby offering more active sites. Additionally, the interface electron reconstruction resulted in lower interfacial charge transport resistance (2.12 Omega), enabling faster catalytic reaction kinetics. As a bifunctional electrocatalyst, the NiMnP/Ni2P/MnP4/NF composite achieved a current density of 10 mA cm-2 with 57 mV and 74 mV for HER overpotential in acidic and basic electrolytes, respectively, close to the Pt/C catalyst (31 mV in acidic and 57 mV in basic). Its OER overpotential was only 232 mV@ 10 mA cm-2, even lower than the noble metal OER catalyst of RuO2 (260 mV@ 10 mA/cm2). Moreover, in overall water splitting tests, the NiMnP/Ni2P/MnP4/NF & Vert;NiMnP/Ni2P/MnP4/NF cell required only 1.54 V to reach 10 mA cm-2, comparable to that of all-pure-precious-metal cell (1.52 V in Pt/C & Vert;RuO2).

The development of efficient and durable nonprecious electrocatalysts for the oxygen evolution reaction (OER) is critical for sustainable hydrogen production. In this study, a defective CoFe-layered double hydroxide (LDH) support is engineered to stabilize isolated cerium atoms via a facile one-step coprecipitation approach. The resulting single-atom catalyst, denoted Ce0.2CoFe-LDH, is thoroughly characterized by atomic-resolution electron microscopy and synchrotron-based X-ray spectroscopy, which confirm the atomic dispersion of Ce3+ species anchored at cation vacancy sites within the LDH matrix. A strong electronic interaction between Ce and Co/Fe sites is observed, leading to charge redistribution that increases the valence states of transition metals and activates dynamic Ce3+/Ce4+ redox cycling. The optimized catalyst exhibits outstanding OER performance in alkaline media, achieving an overpotential as low as 227 mV at 10 mA·cm-2, a Tafel slope of 48.3 mV·dec-1, and excellent stability over 50 h of continuous operation. Electrochemical measurements indicate facilitated charge transfer and an increased electrochemically active surface area. First-principles calculations further reveal that Ce atoms occupying Co vacancies significantly optimize the adsorption of reaction intermediates, reduce the energy barrier of the rate-determining step to 1.81 eV, and induce metallic character through an upshift of the d-band center. This work establishes defect-driven single-atom anchoring as an effective strategy for electronic structure modulation and reaction pathway optimization in LDH-based electrocatalysts, offering valuable insights for the design of high-performance energy conversion materials.

Abstract In this work, multi-period InAs/GaAs sub-monolayer quantum dot (SML-QDs) structures embedded with Al 0 . 3 Ga 0 . 7 As barrier insertion layers of 0, 1, 2, and 3 nm were prepared by molecular beam epitaxy under a fixed total barrier thickness. The morphology, strain, and optical properties of the samples were thoroughly evaluated through atomic force microscopy, high-resolution x-ray diffraction (HRXRD), and temperature-dependent photoluminescence (PL) spectroscopy. The experimental results demonstrate that the sample with a 3 nm Al 0 . 3 Ga 0 . 7 As insertion layer exhibits superior optical quality at room temperature (300 K), manifesting both the highest PL emission intensity and the narrowest full width at half maximum (16.3 nm). Moreover, temperature-dependent PL spectroscopy and Arrhenius fitting analysis indicate that this sample retains a certain PL intensity at 250 K, and its carrier activation energy reaches as high as 105 meV. Therefore, incorporating the Al 0 . 3 Ga 0 . 7 As barrier insertion layer can effectively suppress the carrier thermal escape that readily occurs at high temperatures in InAs/GaAs SML-QDs, thereby improving the device emission efficiency.

Transition metal phosphides, owing to their hydrogenase-like structure, are theoretically expected to exhibit excellent electrocatalytic performance. However, in practice, their performance often falls short due to the phosphorus loss and the insufficient active sites in the electrochemical processes. In this study, the NiCo-LDH nanosheet coating was applied to the NiCoP nanorod array, which not only prevented the loss of phosphorus during electrochemical processes but also provided abundant active sites, thereby significantly enhancing its electrocatalytic performance. Specially The phosphorus mass loss in NiCoP was 8.3% during the electrochemical processes, whereas in the NiCo-LDH@NiCoP composite, it dropped to 1.12%.The as-prepared NiCo-LDH@NiCoP/NF composite exhibited excellent catalytic activity for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). At 10 mA cm-2 in 1.0 M KOH, its HER overpotentials was only 59 mV, very close to that of Pt/C (58 mV). However, when the current density exceeded 192 mA cm-2, the HER performance of the NiCo-LDH@NiCoP/NF surpassed that of Pt/C catalyst, with the HER overpotentials being to 233 mV at 200 mA cm-2 and 260 mV at 300 mA cm-2, significantly lower than those of the Pt/C catalyst (236 mV@200 mA cm-2 and 295 mV @ 300 mA cm-2). It also demonstrated excellent OER capability 1.0 M KOH, with an OER overpotential of merely 190 mV at 10 mA cm-2, much lower than that of RuO2 catalyst (260 mV). Consequently, the electrolytic cell structured with the bifunctional electrodes (NiCo-LDH@NiCoP/NF||NiCo-LDH@NiCoP/NF) required only 1.4 V@10 mA cm-2 in 1.0 M KOH for full water electrolysis, significantly outperforming that of the cell using full noble metal cell (1.51 V for Pt/C||RuO2).

Metal halide perovskite nanocrystals (NCs) are promising luminescent materials for optoelectronic applications. However, the highly sensitive nature of the perovskite lattice to water significantly limits the perovskite NCs for photocatalysis in aqueous phase. Here, we present a core-shell engineering strategy based on an epoxide-mediated sol-gel process to grow metal oxides on the surfaces of perovskite NCs. Benefit from the versatile inorganic metal salts, different metal oxides (such as SnO2, Al2O3, and Eu2O3) are deposited onto the perovskite core under ambient conditions. Owing to the protection of dense metal oxide shell, the exemplified SnO2@CsPbBr3 NCs display intense emission after annealing and slightly photoluminescence (PL) quenching in water over 30 days. Interestingly, they additionally behave outstanding dispersibility in water (with a zeta potential of ∼42 mV). These features, combined with the type II band alignment of SnO2@CsPbBr3 NCs facilitating the photo-generated charge separation, result in a NH4 + production rate of 47 µmol g-1·h-1 without any sacrificial agents. This work explores a generalized approach to produce core-shell structured perovskite NCs to enhance their aqueous stability. Besides, it also expands the aqueous applications of perovskite communities and gives a guideline for designing novel nitrogen fixation photocatalysts.