Low-temperature Hydrothermal Method Research Articles

Structural, optical and temperature dependent electric modulus property of few layer MoS2 nanosheets

Few layered molybdenum di-sulphide (MoS2) nanosheets were synthesised using low temperature hydrothermal method. Hexagonal structure of MoS2 nanosheets was confirmed by the X-ray diffraction (XRD) and Raman spectroscopy techniques. High resolution transmission electron microscopy (HRTEM) studies revealed the formation of 5–6 layered nanosheets with thickness of 3–4 nm. Crystalline size and micro strain in MoS2 were calculated by various model including Williamson-Hall plot, Size-strain plot, Halder-Wagner and Scherrer formula. UV–Vis studies reveal sharp absorption cut off at 216 nm and large band gap of 2.67 eV caused by quantum confinement effect and lattice strain induced shift of orbital overlapping. Difference between two Raman peaks of 24 cm−1 confirmed the formation of 5–6 layers. Very high dielectric constant of 2600 was obtained at room temperature. Temperature dependent complex electric-modulus and dipolar relaxation of MoS2 nanosheets was investigated to understand the relaxation process and transport of charge carriers for the first time.

Composite of iron phthalocyanine and reduced graphene oxide with low temperature hydrothermally grown Ti3C2Tx Mxene for ORR catalytic application

In this paper, Ti3C2Tx MXene was successfully prepared by a mild and environment-friendly low-temperature hydrothermal method. On this basis, the compsites FePc-M-rGO consisting of iron phthalocyanine (FePc), Ti3C2Tx MXene and reduced graphene oxide (rGO) were prepared through simple mixing and used as catalysts for oxygen reduction reaction (ORR). The materials were characterized by SEM, XRD and other methods. The effects of raw material ratio, hydrochloric acid concentration, reaction temperature and reaction time on the properties of Ti3C2Tx were studied in detail. Compared with hydrofluoric acid (HF) etching method, the Ti3C2Tx prepared by low-temperature hydrothermal method has larger layer spacing, more complete crystal structure, larger specific surface area and better conductivity. The influences of different ratios of each component of FePc-M-rGO on the ORR catalytic performances were investigated. Mainly attributed to the improvement of self stacking and uniform adhesion of FePc between Ti3C2Tx layer and graphene nanosheets, the optimized composite material has better ORR activity than commercially available Pt-C catalysts and has good application prospects. This work provides a new approach for the rapid and effective preparation of Ti3C2Tx Mxene, and provides new ideas for the design of non-noble metal catalysts for ORR.

MoS2 modified g-C3N4 composite: A potential candidate for photocatalytic applications

A potential photocatalytic activity of MoS2-modified g-C3N4 composite for methylene blue (MB) dye degradation is processed under sunlight radiation. The photocatalyst materials (g-C3N4, MoS2, and g-C3N4/MoS2) were prepared by low-temperature hydrothermal method and the synthesized samples were further characterized through the X-ray diffraction (XRD), UV–vis diffuse reflectance spectrometer (DRS), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and Photoluminescence (PL) spectroscopy techniques. Initially, the formation of the crystalline structure of (g-C3N4, MoS2, and g-C3N4/MoS2) samples was identified through the XRD technique. Further, the morphology of the MoS2-modified g-C3N4 when observed through SEM was found to be a regular structure with minute pores and voids when compared to the other two samples resulting in better light absorption capacity. The elemental composition of synthesized composite is analyzed by XPS spectra. The energy band gap investigated through the DRS spectra was 2.9 eV, 1.8 eV and 1.82 eV for the g-C3N4, MoS2, and g-C3N4/MoS2 samples respectively. Further BET, TOC and scavenger radical analysis was conducted on the tested sample to analyze the degradation process. Thus, the composite photocatalyst material of MoS2-modified g-C3N4 has an enhanced recombination electron-hole pair rate. Finally, the photocatalytic feature of the composite (g-C3N4/MoS2) tested on MB dye solution under sunlight irradiation for 2 hr was found to be successful.

Centrosymmetric Rb2Sb(C2O4)2.5(H2O)3 and Noncentrosymmetric RbSb2(C2O4)F5: Two Antimony (III) Oxalates as UV Optical Materials.

Herein, we have successfully synthesized two rubidium antimony (III) oxalates, namely, Rb2Sb(C2O4)2.5(H2O)3 and RbSb2(C2O4)F5, utilizing a low-temperature hydrothermal method. These two compounds share a similar chemical composition, consisting of Sb3+ cations with active lone pair electrons, alkali metal Rb+ ions, and planar π-conjugated C2O42- anions. However, they exhibit different symmetries, Rb2Sb(C2O4)2.5(H2O)3 is centrosymmetric (CS), while RbSb2(C2O4)F5 is noncentrosymmetric (NCS), which should be caused by the presence of F- ions. Notably, the NCS compound, RbSb2(C2O4)F5, demonstrates a moderate second-harmonic generation (SHG) response, approximately 1.3 times that of KH2PO4 (KDP), and exhibits a large birefringence of 0.09 at 546 nm. These characteristics indicate that RbSb2(C2O4)F5 holds promising potential as a nonlinear optical material for ultraviolet (UV) applications. Detailed structural analysis and theoretical calculations confirm that the excellent optical properties arise from the synergistic effects between Sb3+ cations with SCALP and planar π-conjugated [C2O4]2- groups.

Preparation and Performance Study of ZnO Nanorod Array with Anti-Ultraviolet and Superhydrophobic Surface

A two-step low-temperature hydrothermal method was used to construct an aluminum-nickel compound network structure on the substrate surface, followed by a secondary hydrothermal synthesis of ZnO nanorod array. After low surface energy material modification, a superhydrophobic and superoleophobic surface was obtained. The aluminum-nickel compound network structure plays a key guiding role in the growth of ZnO nanorod arrays. The uniformly shaped and densely arranged ZnO nanorod arrays have high roughness and exhibit excellent hydrophobic properties after modification. The surface of the ZnO nanorod array is improved in terms of UV resistance due to the size effect. The effects of hydrothermal reaction temperature, hydrothermal reaction time, hydrothermal reaction pH value, and Zn[Formula: see text] concentration on the surface structure, morphology, and properties of the ZnO nanorod array were also studied.

Preparation of magnetic CuO/Fe3O4/ZnO photocatalyst for complete degradation of methylene blue under natural sunlight irradiation

A ternary CuO/Fe3O4/ZnO photocatalyst was successfully produced using a low-temperature hydrothermal method. Subsequently, the prepared photocatalyst was used to degrade Methylene Blue (MB) dye under natural sunlight irradiation. In this system, the catalyst gained magnetic properties by incorporating Fe3O4 in the ZnO nanostructure. However, the resulting photocatalytic performance was reduced, compared to the bare ZnO. To remedy this issue, a p-type CuO semiconductor was coupled to form a p-n junction between CuO and ZnO. The optimal content of CuO was 0.3 mole percent. The ternary CuO/Fe3O4/ZnO composite enhanced the removal efficiency (100%), while the mineralization was about 51.4% within 50 min under sunlight irradiation in a neutral medium. The as-prepared catalyst retained its efficiency to degrade MB dye and remained highly stable, even after six consecutive cycles. The degradation mechanism was investigated based on identifying the degradation products using liquid chromatography-mass spectrometry.

Study on energy storage characteristics of self-assembly Zn-Co-oxide microspheres composite

Rambutan-like ZnCo2O4 microsphere was successfully synthesized on foam nickel (NF) by facile low-temperature hydrothermal method. The unique structure is composed of nanorods by self-assembly, eventually resulting in a porous hierarchical structure consisting of microspheres in the center and spiny nanorods growing outward. The specific capacity of ZnCo2O4/NF remains at 877.91 mAh g−1 after 400 cycles with a current density of 0.2 A g−1 and 723.33 mAh g−1 at a current density of 1 A g−1 in the rating performance. Its excellent cycling and rating performance is attributed to its unique hierarchical mesoporous structure and high carrier transport efficiency. In addition, the hierarchical structure improves the pseudo-capacitance effect at the electrode interface, enhancing the additional reversible capacity and charge/discharge capability.

CuS Nanoparticles Modified ZnO/CdS Dual Direct Z-type Heterostructure Nanocomposite for Efficient Visible-Light Photocatalytic Degradation RhB

The low-temperature hydrothermal and water bath methods are used to manufacture CuS@ZnO/CdS catalyst. The Rhodamine B degradation rate constant of CuS@ZnO/CdS is around 1.53 × 10−2 min−1, which is 3.9 times greater than that of ZnO. The coupling of CdS and loading of CuS onto ZnO surfaces were evaluated using XRD, SEM, TEM, and XPS. SEM demonstrated that 5 mg of CdS was the most effective in controlling the shape of ZnO nanoflakes. Ultraviolet-visible absorption (UV–vis) and Photoluminescence (PL) spectra reveal that CdS and CuS decreased the bandgap of ZnO and boosted its ability to absorb visible light. Transient photocurrent response (TPR) and electrochemical impedance spectra (EIS) display that CdS and CuS facilitate the quick separation of photoexcited carriers in ZnO. Notably, the optimal weight ratio of CuS was determined to be 15%, since excessive amounts of CuS would operate as recombination centers and cover active sites. Additionally, the dual Z-scheme carriers movement mechanism was proposed using sacrificed agent experiments, and TOC analyzed the mineralization rate of RhB after degradation. In this study, CuS@ZnO/CdS photocatalyst degraded RhB nearly 99% in 80 min, which is superior to the earlier photocatalysts. Therefore, this article holds great significance in the practical application of metal chalcogenide-modified ZnO-based photocatalysts with superior visible light-induced degradation performance in environmental purification.

In-Situ Anchoring Ultrafine ZnS Nanodots on 2D MXene Nanosheets for Accelerating Polysulfide Redox and Regulating Li Plating.

Lithium-sulfur (Li-S) battery is a promising energy storage system due to its cost effectiveness and high energy density. However, formation of Li dendrites from Li metal anode and shuttle effect of lithium polysulfides (LiPSs) from S cathode impede its practical application. Herein, ultrafine ZnS nanodots are uniformly grown on 2D MXene nanosheets by a low-temperature (60°C) hydrothermal method for the first time. Distinctively, the ZnS nanodot decorated MXene nanosheets (ZnS/MXene) can be easily filtered to be a flexible and freestanding film in several minutes. The ZnS/MXene film can be used as a current collector for Li metal anode to promote uniform Li deposition due to the superior lithiophilicity of ZnS nanodots. ZnS/MXene powders obtained by freeze drying can be used as separator decorator to address the shuttle effect of LiPSs due to their excellent adsorbability. Theoretical calculation proves that the existence of ZnS nanodots on MXene can obviously improve the adsorption ability of ZnS/MXene with Li+ and LiPSs. Li-S full cells with composite Li metal anode and modified separator exhibit remarkable rate and cycling performance. Other transition metal sulfides (CdS, CuS, etc) can be also grown on 2D MXene nanosheets by the low-temperature hydrothermal strategy. This article is protected by copyright. All rights reserved.

Cotton-Based Activated Carbon Fiber with High Specific Surface Area Prepared by Low-Temperature Hydrothermal Carbonization with Urea Enhancement

The traditional preparation method of activated carbon fiber is high-temperature carbonization and activation. In this experiment, cotton-based activated carbon fiber was prepared by urea-enhanced low-temperature hydrothermal carbonization and activation method. A specific surface area of 2304.8 m2/g of activated carbon fiber prepared by low-temperature hydrothermal carbonization with urea enhancement was the maximum reported using biomass as a raw material, which was higher than that of activated carbon fibers prepared by other biomass raw materials. X-ray photoelectron spectroscopy and elemental analysis studies have shown that the form of N transformed and decomposed during the high-temperature process, leading to the separation of C–N. Thermogravimetry mass spectrometry characterization analysis found that K2CO3 of low-temperature hydrothermal-assisted KOH activation may fully react with the N-containing group produced during the carbonization process to generate NH3, which lead to the formation of more pore structures in the carbon materials. The adsorption capacity of activated carbon fiber activated by hydrothermal-assisted KOH for iodine could reach up to 2254.8 mg/g. This process provides a new idea for the preparation of high-performance activated carbon fibers.

Solar light-active S-scheme TiO2/In2S3 heterojunction photocatalyst for organic pollutants degradation

Heterojunction TiO2/In2S3 composite photocatalyst was prepared using a simple low-temperature one-step hydrothermal method. In2S3 nanosheets with a thickness of 1–5 nm were decorated with 20–30 nm TiO2 nanoparticles, forming a stable heterojunction. The electron transfer mechanism and band alignment between TiO2 and In2S3 was studied using X-ray photoelectron spectroscopy and UV–visible spectroscopy, which suggested the formation of an S-scheme heterojunction in TiO2/In2S3 composite. The TiO2/In2S3 composite with a 1:1 mole ratio showed 99.9% photocatalytic degradation of Rhodamine B within 20 minutes of solar light irradiation, which was better than the results for pristine TiO2, pristine In2S3, and their physical mixture, as well as any other previously reported materials of the same kind. The as-prepared TiO2/In2S3 composite showed excellent stability (98% for Rhodamine B) even after five successive reuse cycles. This excellent performance of TiO2/In2S3 was attributed to the S-scheme heterojunction because of an internal electric field, columbic attraction, and band bending. A radical trapping study showed that superoxide radicals O2·- contribute the most to the photocatalytic degradation of Rhodamine B followed by hydroxyl radicals (OH) and holes (hVB+). The use of a low synthesis temperature and a simple, one-step formation method, with no secondary pollutants generated, makes this process an environmentally friendly and sustainable solution for cost-effective wastewater treatment, highlighting its future commercial applications.

Facile Synthesis of Mn-Doped CuO Nanoflower Spheres and Their Enhanced Sensing Performance for Isopropanol

In this work, the Mn-doped CuO nanoflower spheres (CuO-1% Mn nanoflower spheres) are synthesized through a facile low-temperature hydrothermal method. The as-prepared sample is characterized by XRD, SEM, TEM, EDS, XPS, Raman and BET analylsis. The results indicate that the nanoflower spheres with the diameters of 5-10 μm are assembled by a huge number of nanosheets. And, Mn ions are uniformly doped into the CuO nanoflower spheres. The surface areas of the CuO-1% Mn nanoflower spheres is 33.079 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /g. Under the optimize temperature of 235 °C, when the Mn doping amount is 1%, the CuO-1% Mn nanoflower spheres exhibit the best sensing property toward isopropanol, and the response of which is almost 11.5 times higher than that of pure CuO. In a wide range of 1-100 ppm, the CuO-1% Mn nanoflower spheres exhibit linear response in isopropanol detection. The doped sample also exhibit excellent selectivity, repeatability and durability. It is believed that the doping of Mn ions would be the reason of the improvement of sensing properties. Due to the doping introduced more defects and spillover effect, more oxygen anions would be generated and more isopropanol molecules can be oxidized on the surface of the CuO-1% Mn nanoflower spheres. It is believed that product has great application potential in isopropanol detection.

Effect of Hydrothermal and Vapor Thermal Treatments on Apatite Inductivity of Titanate Nanotubes on Anodized Ti-5Nb-5Mo Surface.

Although titanium (Ti) alloys have been widely employed as biomedical materials, they cannot achieve satisfactory osseointegration when implanted in the human body due to their biologically inert nature. Surface modification can enhance both their bioactivity and corrosion resistance. The present study employed a Ti-5Nb-5Mo alloy with a metastable α″ phase. This alloy may undergo phase changes after conventional high-temperature heat treatment, which can deteriorate its properties. This study heat-treated the anodized Ti-5Nb-5Mo alloy by using a low-temperature hydrothermal or vapor thermal method to analyze the effects of heat treatment on its apatite induction. The results revealed that the porous nanotube structure on the surface of the alloy was transformed into anatase nanoparticles after hydrothermal or vapor thermal treatment at 150 °C for 6 h. After immersion in simulated body fluid (SBF) for 7 days, the amount of apatite deposited on the surface of the vapor thermal-treated alloy exceeded that on the hydrothermal-treated alloy. Therefore, post-heat treatment of anodized Ti-5Nb-5Mo by using the vapor thermal method can enhance its apatite inductivity without altering its structure.

Synthesis of type II heterojunction 2D/3D Bi2S3/MIL-88(A) with enhanced photocatalytic activity under visible-light irradiation

The aim of this article is to provide an effective catalyst for using photocatalytic technology to solve the antibiotic pollution. For this purpose, Bi2S3 was loaded on the surface of MIL-88 (A) to prepare rod-shaped composite photocatalyst via a combination of low-temperature hydrothermal and low-temperature water bath methods. The prepared composite photocatalysts were characterized by using SEM, EDS, XRD, FT-IR, UV–vis and XPS. Tetracycline hydrochloride (TC) degradation under visible light was used to gauge the photocatalytic activity of the composite as it was created. The results show that the degradation efficiency of the optimum sample Bi2S3/MIL-88 (A)-0.2 to TC within 120 min in a 10 mg/L TC solution is as high as 93%, which is 5.74 and 4.39 times as high as that of pure MIL-88 (A) and Bi2S3, respectively. The increased photocatalytic activity is ascribed to the type II heterojunctions that develop between Bi2S3 and MIL-88 (A), which contribute to increase the composite's specific surface area and separation efficiency of photogenerated carriers. Additionally, the possible photocatalytic mechanism of the composite photocatalyst is explored in detail by active species capture experiments, transient photovoltage electrochemical impedance spectroscopy and photoluminescence measurements. This research provides a new way to prepare MIL-88 (A)-based type II heterojunction photocatalysts.

Nanodot zirconium trisulfide based highly efficient biosensor for early diagnosis of lung cancer

In present work, we report results of the studies related to the synthesis of nanodot metal chalcogenide (zirconium trisulfide, ∼5.7 nm in size) based biosensing platform for early detection of lung cancer serum biomarker (CKAP4). The nanodot zirconium trisulfide (nZrS3) was synthesized through low temperature hydrothermal method (200 °C for 72 h) and functionalized with 3-aminopropyl triethoxysilane (APTES) molecules via chemical process. To fabricate thin and uniform film onto the pre-hydrolyzed indium tin oxide (ITO) coated glass electrode of functionalized nanomaterials (APTES/nZrS3), an optimized electrophoretic condition (25 V for 60 s) was applied. Further, for covalent immobilization of anti-CKAP4 onto the APTES/nZrS3/ITO electrode, EDC-NHS chemistry was used and for blocking of non-specific binding sites, bovine serum albumin (BSA) was non-covalently immobilized via drop-cast method. The synthesized as well as functionalized nanomaterial and fabricated electrodes were characterized through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Further, the electrochemical response studies of developed biosensing platform i.e., BSA/anti-CKAP4/APTES/nZrS3/ITO were carried out through DPV technique. The biosensing platform has ability to detect CKAP4 biomarker in the range of 100 pg mL−1-800 pg mL−1 with ultra-sensitivity of 68.76 µA [log (pg mL−1)]−1cm−2, notable lower detection limit of 86 pg mL−1 and shelf life upto 36 days. Moreover, the electrochemical data obtained, exhibit a good correlation with the concentrations of the cancer biomarker CKAP4 found in lung cancer patients as determined by the enzyme-linked immunosorbent assay (ELISA) technique.

Ag-Decorated Vertically Aligned ZnO Nanorods for Non-Enzymatic Glucose Sensor Applications.

The non-enzymatic glucose sensing response of pure and Ag-decorated vertically aligned ZnO nanorods grown on Si substrates was investigated. The simple low-temperature hydrothermal method was employed to synthesize the ZnO NRs on the Si substrates, and then Ag decoration was achieved by sputtering. The crystal structure and surface morphologies were characterized by X-ray diffraction, field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The Ag incorporation on the ZnO NR surfaces was confirmed using EDS mapping and spectra. Furthermore, the chemical states, the variation in oxygen vacancies, and the surface modifications of Ag@ZnO were investigated by XPS analysis. Both the glucose/ZnO/Si and glucose/Ag@ZnO/Si device structures were investigated for their non-enzymatic glucose sensing performances with different glucose concentrations. Based on EIS measurements and amperometric analysis, the Ag@ZnO-NR-based glucose sensor device exhibited a better sensing ability with excellent stability over time than pure ZnO NRs. The Ag@ZnO NR glucose sensor device recorded 2792 µA/(mM·cm2) sensitivity with a lowest detection limit of 1.29 µM.

Effect of Co3O4/TiO2 heterojunction photoanode with enhanced photocathodic protection on 304 stainless steel under visible light

The Co3O4/TiO2 compound photoanodes were prepared by anodization and low-temperature hydrothermal method for the photocathodic protection of 304 stainless steel (304SS). The effect of Co3O4 loading on corrosion resistance of 304SS in 3.5 wt% NaCl was studied by changing the cobalt nitrate concentration of hydrothermal solutions, where the photoanodes were immersed in 0.1 M Na2S+ 0.2 M NaOH solution during tests. Compared with pure TiO2, Co3O4/TiO2 shows stronger visible-light absorption, higher separation efficiency of photocarriers, and better corrosion protection in dark. When cobalt nitrate concentration is 1 mM in the reaction solution, the compound exhibits the best protection performance with a coupled potential under illumination/dark of –0.69/–0.45 VSCE. This enhanced corrosion resistance is not only due to the staggered p-n heterojunction at Co3O4/TiO2 interface but also due to the excellent optical absorption activity and electronic storage capacity of Co3O4. Specifically, the p-n internal electric field drives the photoelectrons to flow to the 304SS under illumination. Meanwhile, it triggers the reverse flow once the light is removed. The latter electrons are stored by Co3O4 and then slowly released in the dark, thus realizing the delayed protection. This work provides theoretical support and possible guidance for the design and application of p-n junction photoanode in the photocathodic protection field.

Construction of three‐dimensional crumpled Ni‐Co TMOs for electrochemical energy storage

AbstractDue to excellent electrochemical performances, mixed transition metal oxides (TMOs) as electrode materials have attracted scholarly attention. However, the issues of volume expansion, unstable structure, and low electrical conductivity have limited their development for lithium battery (LIB). Drawing on the strategy of MOFs derivation synthesis combined with low temperature hydrothermal method, this study successfully synthesized the three‐dimensional (3D) NiCo2O4@Fe2O3 with a flower‐like crossing channel and a surface crumpled structure. As anode for LIBs, NiCo2O4@Fe2O3 exhibits more reliable performance than Ni−Co oxides. Our experiments verified that the Ni−Co composite electrical conductivity and cycling stability were both improved by the Fe2O3 coating. Under the high current density of 1000 mA g−1, the capacity decay rate of NiCo2O4@Fe2O3 tends to be stable after 60 cycles, and the capacity remains at 945 mAh g−1 after 400 cycles. Besides, the specific crossing porous‐channel structure mode improved the composite's carrier transport efficiency, and coulombic efficiency reached 100 % after 400 cycles. Noteworthy is the fact that the crumpled surface structure formed by the 2D Ni−Co nanosheets promotes the construction of heterostructures, further enhances the interface capacitance effect, and strengthens the rating capacity.

In-depth knowledge of the low-temperature hydrothermal synthesis of nanocrystalline hydroxyapatite from waste green mussel shell (Perna Viridis)

ABSTRACT This study presents the use of a low-temperature hydrothermal method for extracting calcium sources from green mussel shell (P. Viridis) wastes and converting them into synthetic nanosized hydroxyapatite (HA). In this study, raw mussel shells were washed, pulverised, and sieved to start producing a fine calcium carbonate-rich powder. XRD quantitative analysis confirmed that the powder contains 97.6 wt. % aragonite. This powder was then calcined for 5 h at 900 °C to remove water, salt, and mud, yielding a calcium-rich feedstock with major minerals of calcite (68.7 wt.%), portlandite (24.7 wt.%), and minor aragonite (6.5 wt.%). The calcined powders were dissolved in aqueous stock solutions of HNO3 and NH4OH before hydrothermally reacting with phosphoric acid [(NH4)2HPO4], yielding pure, nanoscale (16-18 nm) carbonated HA crystals, according to XRD, FT-IR, and SEM analyses. The use of a low-temperature hydrothermal method for a feedstock powder produced by the calcination of low-cost mussel shell wastes would be a valuable processing approach for the industry's development of large-scale hydroxyapatite nanoparticle production.

Photocatalytic oxygen reduction reaction over copper-indium-sulfide modified polymeric carbon nitride S-scheme heterojunction photocatalyst

Photocatalytic oxygen reduction reaction (ORR) to produce hydrogen peroxide (H2O2) has been regarded as an environmentally friendly strategy compared with the anthraquinone oxidation process. Superior photocatalytic activity strongly depends on the efficient separation of charge carriers. Herein, the step-scheme (S-scheme) heterojunction catalysts (CuInS2/PCN) over copper-indium-sulfide (CuInS2) modified polymeric carbon nitride (PCN) were constructed via in-situ low-temperature hydrothermal method. The difference of Fermi levels between PCN and CuInS2 promoted the spontaneously charge transfer directing from CuInS2 to PCN, leading to the construction of built-in electric field at the interface. The S-scheme heterojunction was successfully formed on the effect of built-in electric field, whereby offered a new charge transfer route resulting in efficient migration and strong redox abilities of photogenerated electrons and holes. The optimized H2O2 yield of 3CuInS2/PCN (1247.6 µmol·L−1·h−1) was nearly 11.6 and 16.0 times higher than PCN (107.4 µmol·L−1·h−1) and CuInS2 (78.0 µmol·L−1·h−1), respectively, and the apparent quantum yield (AQY) for H2O2 production over 3CuInS2/PCN reached 16.0 % at 420 nm. Photo-irradiated Kelvin probe force measurement revealed the S-scheme charge transfer mechanism between PCN and CuInS2. This work offers a facile surface modification method for the design of photocatalyst in photocatalytic selective oxygen reduction reaction.