Direct Z-scheme Heterostructure Research Articles

Investigation on thermodynamic stability and electronic structure properties of Bi2CrO6 (0 0 1) surface using density functional theory

A density functional theory (DFT)-based thermodynamic approach was applied to investigate the stability and analyze the surface electronic structures of potential termination structures for the Bismuth chromate (Bi2CrO6) (001) surface. Five Bi2CrO6 (001) surface terminations can be stabilized under certain thermodynamic equilibrium conditions, according to the constructed Bi-Cr-O surface phase diagrams, which are based on calculated surface Gibbs free energies. Analysis of the surface electronic structure shows that O-Bi surface termination has high potential for photocatalytic applications. Additionally, the work functions exhibit substantial differences across various Bi2CrO6 surface terminations, implying that by selecting the thermodynamically more stable surface termination under suitable conditions, the performance of the direct Z-scheme heterostructure based on Bi2CrO6 can be optimized. These findings offer a valuable approach for subsequent experimental research on Bi2CrO6-based photocatalysts and facilitate the investigation of the intrinsic characteristics of Bi2CrO6 surfaces.

Constructing a 3D Bi2WO6/ZnIn2S4 direct Z-scheme heterostructure for improved photocatalytic CO2 reduction performance

Developing efficient heterojunction photocatalysts with enhanced charge transfer and reduced recombination rates of photogenerated carriers is crucial for harnessing solar energy in the photocatalytic CO2 reduction into renewable fuels. This study employed electrostatic self-assembly techniques to construct a 3D Bi2WO6/ZnIn2S4 direct Z-scheme heterojunctions. The unique 3D structure provided abundant active sites and facilitated CO2 adsorption. Moreover, the optimized Bi2WO6/ZnIn2S4 composite demonstrated an impressive CH4 yield of 19.54 μmol g−1 under 4 h of simulated sunlight irradiation, which was about 8.73 and 16.30-fold higher than pure ZnIn2S4 and Bi2WO6. The observed enhancements in photocatalytic performance are attributed to forming a direct Z-scheme heterojunction, which effectively promotes charge transport and migration. This research introduces a novel strategy for constructing photocatalysts through the synergistic effect of morphological interface modifications.

Direct Z-scheme β-SnSe/HfS2 heterostructure for photocatalytic water splitting: High solar-to-hydrogen efficiency and excellent carrier mobility

Constructing directly stacked Z-scheme van der Waals (vdW) heterostructures of different two-dimensional (2D) monolayers is one effective approach to developing highly efficient photocatalysts. In this study, a β-SnSe/HfS2 heterostructure is designed, and its electronic properties and photocatalytic water splitting performance are systematically investigated through first-principles calculations. The charge density difference and work function indicate the presence of an electric field within the heterostructure, further demonstrating its characteristic direct Z-scheme heterostructure. The heterostructure exhibits excellent photocatalytic activity with higher light absorption coefficients of up to 6.67 × 105 cm−1 in the visible and ultraviolet regions compared to the two monolayers alone. The heterostructure possesses high electron mobility in the x direction (2405.86 cm2s−1V−1) and high hole mobility in the y direction (537.56 cm2s−1V−1), facilitating the separation of electron-hole pairs. According to Gibbs free energy, the heterostructure can split water spontaneously overall in acidic settings and only needs an extra potential of 0.64 eV to do so in neutral situations. It is anticipated that the heterostructure have a solar-to-hydrogen (STH) efficiency of up to 14.29%. Because of this, the β-SnSe/HfS2 heterostructure possesses a significant amount of promise for use as a photocatalyst in the generation of hydrogen through the process of water splitting.

Direct Z-scheme MS2/Si2PAs (M = Zr, Hf) heterostructures for efficient water splitting: A first-principles study

Designing direct Z-scheme heterostructure is an effective strategy to enhance redox ability, greatly raising the attention of photocatalysis in recent years. Here, we design 24 diverse vertical MS2/Si2PAs (M = Zr, Hf) heterostructures with different stacking configurations. Four kinds of heterostructures with different interlayer contacts are taken as examples to investigate the geometry, stability, and electronic properties, as well as the photocatalytic mechanism based on the first-principles calculations. We find that the competitiveness of MS2/Si2PAs (M = Zr, Hf) heterostructures is attributed to their excellent visible light absorption (∼2 × 105 cm−1), ultrafast carrier migration (∼13 587.28 cm2 V−1 s−1), and high solar-to-hydrogen efficiency (10.02%), indicating that this kind of system can be as a promising candidate in the field of semiconductor photocatalysis.

A direct Z-scheme BS/PtO2 van der Waals heterojunction for enhanced visible-light photocatalytic water splitting: a first-principles study.

A direct Z-scheme heterostructure holds a unique advantage in solar-driven overall water splitting, while the rational design of efficient photocatalysts for water splitting in such heterostructures remains a challenge. Based on first-principles calculations, this study proposes a novel direct Z-scheme two-dimensional (2D) van der Waals (vdW) heterostructure photocatalyst, denoted as BS/PtO2. Its band edges match the oxidation-reduction potentials of water, satisfying the conditions for the oxidation and reduction of water. Under acidic conditions (pH = 0), the results of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) indicate that BS/PtO2 can drive the OER without the need for an external bias, while the HER requires catalytic assistance. Interestingly, compared to single-layer materials, this heterostructure exhibits a significant enhancement in visible light absorption, implying a more efficient solar energy conversion capability. Therefore, the BS/PtO2 heterostructure holds the potential to become a promising direct Z-scheme photocatalyst with efficient visible light activity.

Direct Z-scheme MoSTe/g-GeC heterostructure for photocatalytic water splitting: A first-principles study

In this paper, based on the first-principle calculations of hybrid density functional theory, the MoSTe/g-GeC of the Z-scheme heterostructure is constructed. The stability, electronic properties, optical absorption properties, and photocatalytic mechanism of the heterostructure is investigated. The band structure of MoSTe/g-GeC heterostructure is staggered, and the bandgap is 0.47 eV. The built-in electric field from g-GeC to MoSTe, with a size of 1.03 eV. The optical absorption coefficient of MoSTe/g-GeC heterostructures is significantly higher than that of MoSTe and g-GeC layer. When pH ranges from 0 to 7, the reduction reaction occurs in g-GeC layer, and the oxidation reaction occurs in the MoSTe layer. In the MoSTe/g-GeC heterostructure under different stresses, the band structure is arranged in a staggered manner. Importantly, under tensile strain, the bandgap of MoSTe/g-GeC heterostructure can be changed from the indirect into a direct bandgap. The bandgap of heterostructure decreases under the strain. In addition, the analysis of the photocatalytic mechanism shows that the redox reaction of the MoSTe/g-GeC heterostructure occurs on the layer with strong redox ability, and their light absorption ability is significantly enhanced compared to single-layers, which effectively improves the photocatalytic properties. It's a potential high-efficiency photocatalytic materials for direct Z-scheme heterostructure.

Electronic properties and applications of MoSSe/MoSTe heterostructure in photocatalytic water splitting

Monolayer material’s electronic properties can be controlled by constructing heterostructures, such as transition metal dichalcogenides (TMDCs) heterostructures. Among them, heterostructures with a new direct Z-scheme electronic band structure are promising solar-driven water splitting photocatalysts. In this work, the first principle calculation based on Density functional theory (DFT) was used to study the structure, electrical properties and optical properties of MoSSe/MoSTe heterostructures. By vertically stacking MoSSe and MoSTe monolayers and via lattice relaxation, 12 different MoSTe/MoSSe heterostructure models have been constructed. Model 1 (TeMoS/SeMoS) and model 2 (SMoTe/SMoSe) are novel direct Z-scheme heterostructure and traditional type II band configurations, respectively. Compared to type II heterostructures, direct Z-scheme arrangement can achieve more efficient spatial separation of photogenerated carriers, increase the lifetime of minority carriers while retaining the redox ability of internal carriers. And compared to monolayer materials, MoSTe/MoSSe heterostructures exhibit stronger and broader optical absorption. Additionally, the conduction band edge potential of MoSTe in the heterostructure is negative to the H+/H2O electrode potential, and the valence band edge potential of MoSSe is positive to the O2/H2O electrode potential. It can be inferred that MoSTe/MoSSe heterostructure has strong reduction and oxidation capabilities, and can achieve total water-splitting reaction. Further Gibbs free energy calculation found that the MoSSe/MoSTe heterostructure can spontaneously conduct thermodynamic water splitting under the light in both acidic and neutral environments, and the theoretical hydrogen production efficiency is 16.7 %.

Construction of Z-Scheme MoS2/ZnFe2O4 heterojunction photocatalyst with enhanced photocatalytic activity under visible light

Construction of direct Z-scheme heterostructure photocatalysts with improved photogenerated charge carriers has gained considerable attention during the past few years. In this work, a direct Z-scheme MoS2/ZnFe2O4 heterostructure photocatalyst was synthesized via a facile hydrothermal method. The photocatalytic activity of this photocatalyst was evaluated through degradation of methylene blue (MB) dye under visible light irradiation. The MZF-25 catalyst showed high catalytic activity with a degradation efficiency of 92.3%, higher than that of pristine MoS2 and ZnFe2O4. Further, the reusability of the MoS2/ZnFe2O4 heterostructure was analysed and there was no significant loss in the photocatalytic activity even after four cycles. Finally, the Z-scheme mechanism of the MoS2/ZnFe2O4 photocatalyst was determined for the degradation of MB. This work provides a promiosing strategy for designing MoS2/ZnFe2O4-based Z-scheme heterostructures for removal of organic pollutants.

Design of a direct Z-scheme GeC/arsenene van der Waals heterostructure as highly efficient photocatalysts for water splitting

The utilization of heterostructures as photocatalysts for water decomposition is a promising method to tackle contemporary environmental challenges. This research paper presents the design of a direct Z-scheme heterostructure utilizing a monolayer of GeC and a monolayer of arsenene, based on first-principle calculations. The photocatalytic efficiency of this GeC/arsenene van der Waals (vdW) heterostructure in a direct Z scheme has been investigated. The presence of a built-in electric field from the GeC monolayer to the arsenene monolayer has been established through an analysis of band alignment, work function, charge density, and Bader charge. The GeC/arsenene heterostructure exhibits excellent and robust optical absorption efficiency for the sunlight, alongside achieving the maximum solar-to-hydrogen (STH) energy conversion efficiency, amounting to 7.28%, under a biaxial strain of +4%. Furthermore, the Gibbs free energy changes in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) of the GeC/arsenene heterostructure have been calculated. The outcomes indicate that the GeC/arsenene heterostructure is a feasible semiconductor for photocatalytic water splitting.

Construction of Bi2MoO6/CoWO4 Z-scheme heterojunction for high-efficiency photocatalytic degradation of norfloxacin under visible light: Performance and mechanism insights

In this work, we employed Bi2MoO6 and CoWO4 to fabricate a direct Z-scheme Bi2MoO6/CoWO4 (BMC-x) heterostructure with high redox potential for norfloxacin (NOR) photodegradation. Under visible light (λ > 420 nm) illumination, BMC-x composites displayed excellent photodegradation performance toward norfloxacin. The photodegradation rate of norfloxacin by BMC-30 reached 97.1% within 60 min of illumination, and the apparent rate constant (0.0588 min−1) was 2.42 and 17.8 times those of Bi2MoO6 and the CoWO4, respectively. The photocatalytic performance of BMC-x nanocomposites was mainly ascribed to the more efficient utilization of electrons (e−) and holes (h+) due to the fabrication of a direct Z-scheme heterostructure. In addition, the mechanisms of NOR degradation were investigated through active species capture experiments and ESR analyses, indicating that O− 2and h+ worked as primary components. Furthermore, the NOR photodegradation pathways were investigated by density functional theory (DFT) and intermediates analysis. More importantly, depending on the QSAR predictions and E.colicultivation, the comprehensive toxicity of the final intermediates was lower than that of the parent. Thus, this work offers a feasible idea for the design and construction of Z-scheme heterojunctions for the highly effective degradation of emerging contaminants in water.

Internal electric field enhanced photoelectrochemical water splitting in direct Z-scheme GeC/HfS2 heterostructure: A first-principles study

Designing direct Z-scheme heterostructure photocatalysts has received enormous attention due to the efficient separation of photo-generated carriers in water splitting. Based on first-principles calculations, electronic properties and a photocatalytic mechanism of a GeC/HfS2 van der Waals (vdW) heterostructure are systematically explored. From the analysis of band arrangement and the built-in electric field, the heterostructure, with an indirect bandgap of 0.40 eV, is demonstrated to be a typical direct Z-scheme system. Remarkably, there is also a 0.40 eV interlayer work function difference in the heterostructure, which is helpful to further drive carrier separation and enhance the water splitting ability by partially bending the redox potential of water. The Gibbs calculation shows that the GeC/HfS2 vdW heterostructure can achieve overall photocatalytic water splitting spontaneously under neutral conditions. Moreover, excellent visible light absorption ability (∼5×105 cm−1) and giant carrier mobilities (5823 cm2 V−1 s−1) also make GeC/HfS2 heterostructure highly competitive in numerous photocatalytic materials and optoelectronic devices. The bandgap can be flexibly adjusted by biaxial strain, enabling a wider application of the heterostructure. All these significant properties not only demonstrate the great application potential of GeC/HfS2 heterostructure as photocatalysis but also provide ideas for designing novel electric field-enhanced heterostructures.

Direct Z-Scheme SnSe2/SnSe Heterostructure Passivated by Al2O3 for Highly Stable and Sensitive Photoelectrochemical Photodetectors.

To mimic the natural photosynthesis system, a Z-scheme heterostructure is proposed as a viable and effective strategy for efficient solar energy utilization such as photocatalysis and photoelectrochemical (PEC) water splitting due to the high carrier separation efficiency, fast charge transport, strong redox, and wide light absorption. However, it remains a huge challenge to form a direct Z-scheme heterostructure due to the internal electric-field restriction and vital band-alignment at the interface. Herein, the van der Waals heterostructure based on the allotrope SnSe2 and SnSe is designed and synthesized by a two-step vapor phase deposition method to overcome the limitation in the formation of the Z-scheme heterostructure for the first time. The Z-scheme heterostructure of SnSe2/SnSe is confirmed by X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, PEC measurement, density functional theory calculations, and water splitting. Strikingly, the PEC photodetectors based on the Z-scheme heterostructure show a synergistic effect of superior stability from SnSe and fast photoresponse from SnSe2. As such, the SnSe2/SnSe Z-scheme heterostructure shows a good photodetection performance in the ultraviolet to visible wavelength range. Furthermore, the photodetector shows a faster response/recovery time of 13/14 ms, a higher photosensitivity of 529.13 μA/W, and a higher detectivity of 4.94 × 109 Jones at 475 nm compared with those of single components. Furthermore, the photodetection stability of the SnSe2/SnSe is also greatly improved by a-thin-Al2O3-layer passivation. The results imply the promising rational design of a direct Z-scheme heterostructure with efficient charge transfer for high performance of optoelectronic devices.

Exploring the effects of different crystal facet combinations and I-doping in the BiOCl/BiOI heterostructure on photocatalytic properties: a hybrid density functional investigation.

This study uses hybrid functional calculations to investigate the effects of various crystal facet combinations in BiOCl and BiOI on the photocatalytic activity of the BiOCl/BiOI heterostructure. The results show that the separation efficiencies of photo-generated electron-hole pairs in BiOCl(010)/BiOI(001) and BiOCl(010)/BiOI(010) are constrained by type I band alignments in principle. In contrast, BiOCl(001)/BiOI(001) and BiOCl(001)/BiOI(010) heterostructures, which operate under the direct Z-scheme type, exhibit an enhanced photo-generated charge separation efficiency, superior redox capacity, and enhanced visible light absorption. Specifically, BiOCl(001)/BiOI(010) exhibits a more remarkable reduction ability that can reduce O2 to ˙O2-. Furthermore, our investigations demonstrate that targeted I element doping in BiOCl(001)/BiOI(010) can reduce the band gap of the BiOCl(001) sheet, enhance visible light absorption, and maintain the direct Z-scheme characteristics, thereby further improving the photocatalytic performance. Additionally, we discovered that I doping can transform the BiOCl(010)/BiOI(001) heterostructure from type I into a direct Z-scheme heterostructure, resulting in a substantial enhancement in the separation efficiency and reduction ability of photo-generated carriers as well as visible light absorption with increasing I doping concentration. Considering the excellent charge injection efficiency observed in experiments with the BiOCl(010)/BiOI(001) heterostructure, I-BiOCl(010)/BiOI(001) may represent a superior photocatalyst. Thus, this study highlights the crucial and substantial roles of engineering specific crystal facet combinations and I doping in enhancing the photocatalytic performance of the BiOCl/BiOI heterostructure. This theoretical study contributes to the comprehension of related experimental findings and offers valuable insights for the development of novel BiOCl/BiOI heterostructures with superior photocatalytic activity.

Improving photocatalytic hydrogen production by switching charge kinetics from type-I to Z-scheme via defective engineering.

By providing the spatial separation of the active sites and retaining high oxidative and reducing capacity, the direct Z-scheme heterostructure is considered the most potential structure for yielding photo-electric response. However, challenges still exist in the directional transfer of charge carriers between two semiconductors in direct Z-scheme structures. In this regard, by constructing the Vzn defect and p-n junction, a direct Z-scheme ZnxCd1-xS@ZnS-NiS heterostructure was obtained for the regulated electronic structure, which ensured high-yield hydrogen properties. The Zn vacancy in the partially-coated ZnS shell led to the Vzn energy level, and the addition of NiS led to the p-n structure, which caused a drastic downshift of the band edge potentials in comparison to that of pristine CdS. This variation gave rise to a staggered band edge alignment between ZnxCd1-xS and NiS, resulting in the variation of charge transfer kinetics from type-I to direct Z-scheme. Through careful characterization, it was found that the optimal photocatalytic hydrogen precipitation activity reached 16 683.6 μmol g-1 h-1, which was 70 times that of CdS, and this improvement was considered to form a spatial barrier, providing a clear direction and path for carrier transmission.

PtSe2/SnS2 heterostructure as a direct Z-scheme photocatalyst for water decomposition

The direct Z-scheme heterostructure has attracted much attention due to its strong photocatalytic ability. In the present work, we use density functional theory to explore the electronic and optical properties and photocatalytic mechanism of PtSe2/SnS2 heterostructure. Compared with PtSe2 and SnS2 monolayers, PtSe2/SnS2 heterostructure has smaller band gap and better light absorption capacity. The results of band calculation show that the heterostructure form a band arrangement of type-II. Further work function calculations indicate that the direction of the built-in electric field is PtSe2 to SnS2, indicating the charge transfer mechanism is Z-scheme. In the water decomposition reaction, the free energy calculation results show that water decomposition reaction can occur spontaneously under light. Therefore, PtSe2/SnS2 heterostructure can be used as a potential Z-scheme photocatalyst for hydrogen and oxygen production.

Bismuth Tungstate-Silver Sulfide Z-Scheme Heterostructure Nanoglue Promotes Wound Healing through Wound Sealing and Bacterial Inactivation.

Rapid wound closure and bacterial inactivation are effective strategies to promote wound healing. Herein, a versatile nanoglue, bismuth tungstate (Bi2WO6)-silver sulfide (Ag2S) direct Z-scheme heterostructure nanoparticles (BWOA NPs), was designed to accelerate wound healing. BWOA NPs' hollow structure and rough surface could effectively close wound tissues acting as a barrier between external bacteria and the wound. More importantly, the unique Z-scheme heterostructure endows BWOA NPs with an effective electron and hole separating ability with potent redox potential, where electrons and holes could effectively react with water and oxygen to produce reactive oxygen species, leading to a higher antibacterial activity against both endogenous and external bacteria at the wound site. A series of in vitro and in vivo biological assessments demonstrated that BWOA NPs could rapidly close wounds and promote wound healing. With sunlight irradiation, the inhibiting rates of BWOA NPs against Escherichia coli and Staphylococcus aureus are 61.62 ± 2.85 and 73.40 ± 3.28%, respectively. Also, the wound healing rate in BWOA NP-treated mice is 25.90 ± 5.85% higher than PBS. This design provides a new effective strategy to promote bacterial inactivation and accelerate wound healing.

Two-dimensional MgAl2S4 as potential photocatalyst for water splitting and strategies to boost its performance

Exploring novel 2D water-splitting photocatalysts and finding strategies to boost their efficiency are important tasks in nowadays energy industry. Here, employing first-principle calculations, we predicted a novel 2D material, MgAl2S4 monolayer, and studied its potential applications in photocatalytic water splitting. 2D MgAl2S4 is noble-metal-free and possesses great thermal and dynamical stability. The cleavage energy is around 16 meV/Å2 which is even lower than graphene, indicating the high feasibility for experimental fabrications. The band edge positions and the optical absorption spectra indicate the pristine MgAl2S4 monolayer can work as a photocatalyst upon ultraviolet irradiation. Its high electron mobility around 745 cm2v-1s−1 and high conduction band minimum (CBM) position suggest a strong reduction ability. Furthermore, the oxidation ability and light absorbance can be significantly enhanced by a small tensile strain. The complementary marriage of MgAl2S4 and SnSe2 monolayers can form a direct z-scheme heterostructure, which can fully utilize the photocatalytic potential of both components.

Construction of CdS/CdSnO3 direct Z-scheme heterostructure for efficient tetracycline hydrochloride photodegradation

Photocatalytic technology is one of the promising methods for solving the environmental crisis caused by antibiotics. In this work, CdS/CdSnO3 direct Z-scheme heterojunctions were fabricated through soft-chemistry routes. Various characterizations were performed to analyze the intrinsic properties of the constructed photocatalysts. The photocatalytic activity of the as-prepared catalysts was assessed via tetracycline hydrochloride (TCH) photodegradation. Compared with the bare CdSnO3 and CdS, all the obtained CdS/CdSnO3 heterojunctions exhibited improved photocatalytic performance. Meanwhile, the kinetic constant of CdS/CdSnO3 heterojunction with optimized mass ratio was about 57.5 and 1.85 times as high as the bare CdSnO3 and CdS. The upgraded photocatalytic activity can be attributed to the enhanced light absorption and unique charge transfer path. Based on the systematic analysis, the possible direct Z-scheme photocatalytic mechanism was put forward.

Direct Z-scheme photochemical hybrid systems: Loading porphyrin-based metal-organic cages on graphitic-C3N4 to dramatically enhance photocatalytic hydrogen evolution

The rational design of photochemical molecular device (PMD) and its hybrid system has great potential in improving the activity of photocatalytic hydrogen production. A series of Pd6L3 type metal-organic cages, denoted as MOC-Py-M (M = H, Cu, and Zn), are designed for PMDs by combining metalloporphyrin-based ligands with catalytically active Pd2+ centers. These metal-organic cages (MOCs) are first successfully hybridized with graphitic carbon nitride (g-C3N4) to form direct Z-scheme heterogeneous MOC-Py-M/g-C3N4 (M = H, Cu, and Zn) photocatalysts via π–π interactions. Benefiting from its better light absorption ability, the MOC-Py-Zn/g-C3N4 catalyst exhibits high H2 production activity under visible light (10348 μmol g−1 h−1), far superior to MOC-Py-H/g-C3N4 and MOC-Py-Cu/g-C3N4. Moreover, the MOC-Py-Zn/g-C3N4 system obtains an enhanced turn over number (TON) value of 32616 within 100 h, outperforming the homogenous MOC-Py-Zn (TON of 507 within 100 h), which is one of the highest photochemical hybrid systems based on MOC for visible-light-driven hydrogen generation. This confirms the direct Z-scheme heterostructure can promote effective charge transfer, expand the visible light absorption region, and protect the cages from decomposition in MOC-Py-Zn/g-C3N4. This work presents a creative example that direct Z-scheme PMD-based systems for effective and persistent hydrogen generation from water under visible light are obtained by heterogenization approach using homogeneous porphyrin-based MOCs and g-C3N4 semiconductors.

Solar energy-driven upcycling of plastic waste on direct Z-scheme heterostructure of V-substituted phosphomolybdic acid/g-C3N4 nanosheets

The increasingly massive consumption of plastics is becoming a global pollution disaster, with serious environmental and economic problems. Here we report an efficient and sustainable strategy for the visible-light-driven upcycling of various plastic wastes into high-value-added formic acid. We firstly design and fabricate a self-assembly Z-scheme heterostructure of V-substituted phosphomolybdic acid clusters/g-C3N4 nanosheets (VPOM/CNNS). The Z-scheme charge transfer process is unambiguously elucidated by transient absorption spectra and electron spin resonance studies, which endow VPOM/CNNS heterostructure with efficient charge separation and strong redox potentials. Consequently, VPOM/CNNS heterostructure displays a superior photocatalytic performance toward upcycling of various plastics. The optimal VPOM/CNNS composite exhibits a remarkable formic acid production rate of 24.66 μmol h−1 g−1 for upcycling of polyethylene, which is 262-fold higher than that of pristine CNNS. This work highlights the potential of Z-scheme heterojunction as an unusual tool for the photo-driven upcycling of plastic waste.