Co3O4 Loading Research Articles

Boosted photothermal-assisted photocatalytic H2 production by dual heat source-based S-scheme heterojunction

With advances in catalytic research, improvement of catalytic efficiency by using photothermal synergies to strengthen the reaction mechanisms has been focused. In this work, a novel photothermal-assisted photocatalytic H2 production system was constructed by loading Co3O4 nanoparticles on surface of black carbon nitride (BCN) nanosheets, served as the dual thermal source to enhance photothermal effect for synergistically assisting in photocatalytic H2 evolution with optimal H2 production rate reached 3.7 mmol g−1 h−1, significantly higher than that of pure carbon nitride (CN) and BCN. Moreover, the S-scheme heterojunction is also formed between Co3O4 and BCN, leading to the optimization of the charge transfer path, which further promotes the improvement of photothermal-assisted photocatalytic H2 production activity. This study provides the design idea of coupling the multi-heat source effect with the heterojunction electron transport for constructing an efficient photothermal-assisted hydrogen production system.

Boosting the bifunctional catalytic activity of Co3O4 on silver and nickel substrates for the alkaline oxygen evolution and reduction reactions

Developing an efficient bifunctional catalyst for oxygen reduction (ORR) and evolution reactions (OER) is a crucial step for the wide commercialization of alkaline water electrolyzers. However, a proper assessment and comparison of various catalysts is still challenging due to the different catalyst substrates and loadings. In this work, Co3O4 spinel nanoparticles (NPs) were investigated as a bifunctional catalyst at different substrates of glassy carbon or Ag bulk substrate or Ni particles and with different loadings. For Co3O4 (800 µg cm-2)/Ag electrode, not only the overpotential for ORR was 50 mV lower than the bare Ag electrode, but also the OER overpotential was 40 mV lower than the sole Co3O4. Besides, less than 1% peroxide intermediate was detected during ORR using the rotating ring disc electrode (RRDE) method, suggesting a 4-electron O2 reduction. Tafel slopes of 70 and 60 mV dec‑1 at Co3O4/Ag were obtained for ORR and OER, respectively. The improved bifunctional activity could be attributed to a synergistic effect between Co3O4 and the Ag support. For the loading effect, it is revealed that the number of accessible sites of Ag surface decreases with increasing the Co3O4 loading, as evaluated from lead-underpotential deposition measurements. Interestingly, after running ORR/OER cycles, the surface area increased by 4–6 times. This surface roughening was also confirmed by SEM and EDX. The study was extended to Co3O4+Ni mixed catalyst to validate the effect of the support on this induced synergism. Hence, this work provides a simple route for designing potential effective catalytic interfaces and contributes to unravelling the influence of the substrate and loading on the catalyst activity for water electrolyzers.

Influence of reduced graphene oxide layer on sensing characteristics of Co3O4/rGO nanocomposite towards Liquefied Petroleum Gas (LPG)

Liquefied petroleum gas (LPG), a mixture of different hydrocarbons, is a highly inflammable and explosive gas that is harmful to the environment and human health. Thus, it is imperative to fabricate LPG sensors with higher sensitivity, selectivity, stability, and minimal power consumption, functioning at low temperatures. The current study reports on the monitoring and detection of LPG at low functional temperatures using Co3O4-loaded on rGO (rGO-Co) prepared using the hydrothermal method. The microstructural properties of the materials were investigated in detail. The rGO-Co (80 wt%) sensor showed outstanding sensitivity (0.00364 ppm−1) and selectivity toward LPG, as well as a limit of detection of 1 ppm at a temperature of 125 °C. The sensing mechanism showed that an even distribution of Co3O4 throughout the rGO layers, serving as efficient sites for the adsorption and desorption of LPG molecules, was associated with enhanced gas-sensing capabilities. Furthermore, the response to LPG detection was significantly influenced by the combination of the finite spherical nanoparticles with increased pore sizes between them and reduced energy band gaps. Thus, the novel improvement of the sensor towards LPG detection was linked to the ohmic connection formed between rGO and Co3O4 forming a p-p heterojunction at the interface. Additionally, the coupling of Co-O-C bonds validated by high-temperature X-ray diffraction and X-ray photoelectron spectroscopy provided extra active sites from Co3+ for effective LPG adsorption. The sensing mechanism induced by the loading of Co3O4 on the rGO surface was also deliberated.

Fabrication of WO3/Co3O4 nanorods as a p-n heterojunction photoanode for efficient photoelectrochemical oxygen evolution

Developing efficient photoelectrocatalysts is seen as a promising method for generating hydrogen through photoelectrochemical (PEC) water splitting. In this study, the WO3/Co3O4 heterojunction was fabricated on FTO substrates, serving as an effective photoanode for PEC water splitting. The p-type Co3O4 nanoparticles were loaded onto n-type WO₃ nanorods to create a p-n heterojunction, thereby reducing charge recombination due to the internal electric field at the heterointerface. Under LED illumination (∼80 mW/cm2), the photocurrent density of the WO3/Co3O4 photoanode reached 161.1 μA/cm2 at 1.23 V vs. RHE, which is 2.3 times higher than that of bare WO3 photoanode. The results show that loading Co3O4 onto WO3 nanorods significantly increased the absorption of visible light, boosted charge carrier density, and enhanced surface reaction kinetics. This work indicates the construction of p-n heterojunction photoanodes for achieving effective photoelectrochemical performance.

Co3O4@SiO2 3D Monolith Catalysts, Additive Manufactured Structures for Propane Oxidation Reaction

AbstractIn this study, we successfully fabricated a three‐dimensional Co3O4@SiO2 3D Monolith catalyst. This process allowed for the effective and straightforward anchoring of Co3O4 nanoparticles onto SiO2 3D Monoliths. The active Co3O4 phase was primarily identified through XRD and XPS analyses, complemented by Co3O4 loading measurements (1.7 %). This innovative catalyst displayed remarkable proficiency in selectively converting propane to carbon dioxide. Additionally, it was demonstrated that the catalytic activity remained unimpaired even upon the catalyst's reuse in 5 successive reaction cycles. This performance was observed across various heating ramps, showcasing the catalyst's stability over time.

Hollow Co3O4 nanoparticles on CNF with polydopamine assistance for enhanced supercapacitor electrodes

Transition metal oxides (TMOs) are increasingly recognized as viable cathode materials for pseudocapacitors, due to their substantial theoretical capacity, widespread availability, and environmental benignity. However, their practical application is hindered by significant volumetric expansion during reactions and their inherently limited electrical conductivity. The design of hollow nanoarchitectures, coupled with carbonaceous material integration, has emerged as a potent approach to surmount these limitations. Herein, we reported a stepwise synthesis method where Cobalt oxide (Co3O4) nanoparticles, anchored onto carbon nanofibers (CNF) pre-modified with Polydopamine (PDA) known for its superior adhesion, were transformed into HCo3O4@C@CNF composite materials via a high-temperature annealing process. The mass ratio of Co3O4 to CNF was optimized, with a 3:1 ratio being identified as ideal. This optimized HCo3O4@C@CNF electrode exhibited outstanding electrochemical performance, attaining a significant specific capacitance of 2992 F g-1 at 3 A g-1 and maintaining a 91% capacitance retention rate following 8000 charge-discharge cycles. The CNF acted as an efficient conductive network, substantially enhancing the electrical conductance. Furthermore, the incorporation of PDA facilitated a more uniform dispersion and substantial loading of Co3O4, while the carbon shell, formed upon carbonization, effectively prevented the agglomeration of HCo3O4 nanoparticles, enhancing the overall stability and performance of the electrode. Therefore, the synthesized HCo3O4@C@CNF electrodes exhibit a viable approach for the preparation of electrode materials with high-performance.

Low platinum loading Co3O4 electrode for highly efficient oxidation of ammonia in aqueous solution

Chlorine-mediated electrochemical advanced oxidation (Cl-EAO) is an environmentally-friendly and promising ammonia removal technology to convert ammonia to N2 and effectively reduce water pollution. The efficiency of ammonia removal in Cl-EAO hinges critically on the performance of the electrode materials. Currently, precious metal oxides are commonly used as electrode materials in the industry. However, their high cost limits their widespread application in ammonia treatment. Herein, Pt-Co3O4 catalyst with lutra-low content of Pt (1.67 wt%) is successfully synthesized, which performs superior CER activity and higher removal efficiency of ammonia. The favorable catalytic performance could be attributed to the increase in oxygen vacancy content and the strong metal-supported strong interaction (SMSI) between Pt and Co3O4, which has been confirmed by XPS. Especially, the chlorine evolution efficiency of the Ti/Pt3 %-Co3O4 electrode was as high as 96 % in dilute chloride (<50 mM) solution at a current density of 10 mA/cm2. Therefore, the Ti/Pt3 %-Co3O4 electrode has a broad application prospect as a new and efficient material for ammonia wastewater treatment.

CNTs with nano-confined TiO2 and surface loading Co3O4: The analysis of its performance and mechanism of PMS activation for ECs degradation under visible light

The efficient activation of peroxymonosulfate for degrading emerging contaminants has become a focal point in recent decades, emphasizing the development of novel materials and efficient strategies for high-performance degradation. This study explores a spatial confinement strategy, where TiO2 is confined inside carbon nanotubes with Co3O4 loading outside, is performed to prepare the nano-confined composite TiO2-in-CNT/Co3O4. Norfloxacin is chosen as the primary target pollutant, revealing a degradation rate exceeding 97 % within 30 min. The non-radical 1O2 species were confirmed to be generated in nano-confined catalyst, but not observed in the control non-confined catalyst. Additionally, the quantity of original radical active species significantly increases in nano-confined catalyst compared to non-confined catalyst. TiO2-in-CNT/Co3O4 has excellent reusability and application universality. Wonderful stability is observed in real water and anti-ion interference experiments, highlighting its robust stability. Experimental and DFT calculation results also demonstrate that the spatial confinement strategy prevents nanoparticle aggregation, accelerates electron transfer efficiency, and promotes the cycling of Co2+/Co3+ electron pairs. This work provides insights into the regulation of confined effects in activating PMS and offers a feasible strategy for the synergistic activation of PMS for water environment remediation through a radical and non-radical mixed mechanism.

Effect of hydrofluoric acid-modified Co3O4/Y-type molecular sieves on MFC performance

Microbial fuel cell (MFC) is a green technology that facilitates resource utilization of wastewater by generating electricity while degrading organic and ammonia nitrogen pollutants. The anode plays a crucial role in the MFC performance, demanding excellent electrochemical performance and high stability. In this paper, a new high-performance anode of Co3O4 composite Y molecular sieve (Co3O4/Y) was prepared, and the effect of the Co3O4 ratio and hydrofluoric acid (HF) modification on the Co3O4/Y performance was also investigated. The results showed that the Co3O4/Y, synthesized through the hydrothermal method with 30 wt% loading of Co3O4 followed by 10 % HF treatment, demonstrated superior electrochemical performance, which had the highest redox peak current density, the largest current response area, and the maximum exchange current density of 0.038 mA/cm2. Four anode catalysts of MFC, namely, blank carbon cloth (CC), Co3O4-CC, Co3O4/Y-CC, and H-Co3O4/Y-CC were prepared, and four groups of MFCs were constructed for the treatment of mixed wastewater consisting of the aged landfill leachate and shale gas fracturing wastewater. Notably, the H-Co3O4/Y-CC group showed the best performance in power generation, achieving a maximum stabilized output voltage (448 mV), a maximum power density (1179 mW/m2), and a minimum apparent internal resistance (466 Ω). Additionally, the removal rate of ammonia nitrogen exceeded 40 % in the mixed wastewater of the 4 groups of MFCs. This study provided a viable strategy for fabricating high-performance MFC anode materials and offered insights into the simultaneous disposal of domestic and industrial wastewater in MFCs.

Moss-like porous biochar loading Co3O4 nanoparticles as sulfur host maintain the stability of Li-sulfur batteries

Moss-like porous biochar loading Co3O4 nanoparticles as sulfur host maintain the stability of Li-sulfur batteries

Construction of S-scheme heterojunction catalytic nanoreactor for boosted photothermal-assisted photocatalytic H2 production

Reasonable design of heterojunction band structure and strengthening of the photothermal effect is an important method to promote the photothermal-assisted photocatalytic H2 production activity of photocatalysts. Herein, a composite material named as Co3O4/CNNVs S-scheme heterojunction nanoreactor was constructed by loading Co3O4 nanoparticles on the surface of g-C3N4 nanovesicles (CNNVs) through a simple hydrothermal method and used to achieve efficient photothermal-assisted photocatalytic H2 production. In the absence of Pt as a cocatalyst, Co3O4/CNNVs-22.5 exhibited a photocatalytic H2 production rate up to 772.9 μmol g-1h−1 under irradiation with a 300 W Xenon lamp, which is much higher than that of pure CNNVs (15.5 μmol g-1h−1). In the Co3O4/CNNVs photothermal-assisted photocatalytic system, the synergistic effect of the strong photothermal effect of Co3O4 nanoparticles and the thermal insulation effect of hollow CNNVs nanoreactor was shown to be the main reasons for promoting the surface temperature increase of the heterojunction photocatalyst, which effectively facilitates the separation and transfer of photo-generated carriers, thus increasing the photocatalytic H2 production. In addition, the S-scheme heterojunction formed between Co3O4 and CNNVs optimize the charge transfer path. This work presents a reasonable design of highly efficient photocatalyst with a S-scheme heterojunction nanoreactor for the photothermal-assisted photocatalysis.

Co3 O4 Supported on β-Mo2 C with Different Interfaces for Electrocatalytic Oxygen Evolution Reaction.

Interface engineering is an effective strategy for improving the activity of catalysts in electrocatalytic oxygen evolution reaction (OER). Herein, Co3 O4 supported on β-Mo2 C with different interfaces were investigated for electrocatalytic OER. The morphological diversity of β-Mo2 C supports allowed different Co3 O4 -Mo2 C interactions. Various techniques characterized the composition and microstructure of the interface in the composites. Due to the strong interaction between Co3 O4 nanoparticles and β-Mo2 C nanobelts with opposing surface potentials, compact interface was observed between Co3 O4 active species and β-Mo2 C nanobelt support. The compact interface enhanced the conductivity of the material and also regulated the interfacial electron redistribution of Mo and Co atoms, promoting the charge transfer process during OER. In addition, the surface loading of Co3 O4 can effectively improve the hydrophilicity of the surface. β-Mo2 C has the capability in dissociating H2 O molecules. Thus, an example has been carefully demonstrated for interface engineering in electrocatalytic OER.

Mesoporous Co3O4/In2O3 nanocomposites for formaldehyde gas sensors: Synthesis from ZIF-67 and gas-sensing behavior

Mesoporous In2O3 nanowires (NWs) were synthesized with nanocasting method, and then Co3O4/In2O3 nanocomposites were prepared through calcining ZIF-67. All results indicate that Co3O4 nanoparticles greatly affect the microstructures and gas-sensing properties of Co3O4/In2O3 sensors. The response to 10 ppm (formaldehyde) HCHO gas exhibits a significant improvement though the loading of Co3O4. The response values soar from 26.16 for In2O3 NWs to 92.94 for 6%Co3O4/In2O3 and up to maximum 113.6 for 8% Co3O4/In2O3, then decreases to 25.76 for 10% Co3O4/In2O3. 8% Co3O4/In2O3 sensor possesses the excellent HCHO gas-sensing performance with the highest response (113.6) and shortest response time of 20 s. The working temperature of Co3O4/In2O3 sensors is 30 °C lower than that of In2O3 sensor due to Co3O4 catalysis. P-n heterojunctions between p-type Co3O4 and n-type In2O3 affect the interfacial carrier distribution, improving the gas-sensing behavior of Co3O4/In2O3 sensors. Furthermore, oxygen vacancies also play a important role to improve the gas-sensing performance of Co3O4/In2O3 sensors.

Novel Co3O4@TiO2@CdS@Au double-shelled nanocage for high-efficient photocatalysis removal of U(VI): Roles of spatial charges separation and photothermal effect

Effective spatial separation and utilization of photogenerated charges are critical for photocatalysis process. Herein, novel Co3O4 @TiO2 @CdS@Au double-shelled nanocage (CTCA) with spatially separated redox centers was synthesized by loading Co3O4 and Au NP cocatalysts on the inner and outer surfaces of Z-scheme heterojunction (TiO2 @CdS). The reduction rate constant of U(VI) by CTCA reached 0.218 min−1 under simulated sunlight irradiation, which was 6.6, 3.2 and 36.3 times than that of monolayer CTCA (0.033 min−1), CTC (0.068 min−1) and CT (0.006 min−1). The full-spectrum light-assisted photothermal catalytic performance can enable CTCA to remove 98.8% of U(VI) and degrade nearly 90% of five organic pollutants simultaneously. Detailed characterizations and theory calculations revealed that the photogenerated holes and electrons in CTCA flow inward and outward. More importantly, Co3O4 acts as a “nano heater” to generate the photothermal effect for further enhancing the charge transfer and accelerating the surface reaction kinetics. Meanwhile, the photogenerated electrons and superoxide radicals play a dominant role in reducing the adsorbed U(VI) to insoluble (UO2)O2·2H2O(s). This work provides valuable input toward a novel double-shelled hollow nanocage reactor with excellent photothermal catalysis ability for efficient recovery U(VI) from uranium mine wastewater to address environmental contamination issues.

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.

Novel n-MoSSe/p-Co3O4 Z-scheme heterojunction photocatalyst for highly boosting photoelectrochemical and photocatalytic activity

The development of stable, efficient photocatalyst for environmental antibiotics degradation is great significant and remains a major challenge. Herein, novel 2D/0D n-MoSSe/p-Co3O4 Z-scheme heterojunction catalysts (MSCO) are developed to combine the advantages of n-type MoSSe nanoplates and p-type Co3O4 nanoparticles. With an optimized Co3O4 loading ratio, the MSCO2 sample exhibited 7.8 and 28.8 times of photocurrent density more than that of pure MoSSe and Co3O4, and likewise showed 2.54 and 8.91 times of photocatalytic tetracycline hydrochloride removal rate more than that of pure MoSSe and Co3O4. Moreover, the heterojunction displayed outstanding recyclability after five cycles. The remarkably enhanced catalytic properties were mainly ascribed to the 2D/0D structure, built-in electric field between p-n heterojunction and electron transfer the Z-Scheme pathways which was helpful to promote the separation of photogenerated carriers. Additionally, the corresponding reaction pathway and photocatalytic mechanism were further elucidated by the results of the electron spin resonance (ESR) and high-pressure liquid chromatography-mass spectrometry (HPLC-MS). This research provided a new idea for the construction of Z-Scheme p-n heterojunction with 2D/0D structure in photocatalysis, photoelectrochemistry, and electrocatalysis.

Direct oxidation of cyclohexane to adipic acid in air over Co3O4@ZrO2 nanostructured catalyst

Despite the vast industrial importance of adipic acid (AA), developing sustainable and selective catalysts for the oxidation of cyclohexane using air as an oxidant is a longstanding challenge for researchers. We have synthesized a Co3O4@ZrO2 nanostructured catalyst and found that it converts cyclohexane to AA directly in air without adding any additional reagent. Under mild, environmentally friendly, solvent-free conditions and without any initiators, the catalyst showed a conversion of ∼40% with a selectivity of ∼43% towards adipic acid. NH3-TPD analysis confirmed the presence of acidic sites on Co3O4@ZrO2. According to the findings, loading Co3O4 in the ZrO2 matrix generated a considerable increase in acidity (1.08 mmol/g), and the trend of different loading of cobalt followed the order: 5.4Co3O4@ZrO2 > 3.2Co3O4@ZrO2 > 2.5Co3O4@ZrO2 > 1.6Co3O4@ZrO2. The catalyst was thoroughly characterized by XRD, BET, HR-TEM, SEM, H2-TPR, XPS, NH3-TPD, Pyridine-IR, TGA, Raman, ICP-AES, UV–Visible and EPR spectroscopy. The recyclability and leaching test confirmed the true heterogeneous nature of the catalyst as there was no significant loss of catalytic activity even after 5 cycles.

Heterojunction formation between AgNbO3 and Co3O4 for full solar light utilization with improved charge-carrier separation.

In the present study, the charge-carrier recombination of visible light active perovskite silver niobate (AgNbO3) was reduced by forming heterojunction with Co3O4 through simple impregnation and calcination route. The loading percentage of Co3O4 was varied as 2, 5, and 10 wt.%. The XRD study revealed reduced interlayer spacing in the composite due to the replacement of the bigger Ag+ ions by the smaller Co2+ and Co3+ ions of Co3O4. It was observed that the light harvesting efficiency of the materials was increased with increased loading of Co3O4. The TEM and XPS analysis confirmed the presence of Ag nanoparticles over the perovskite in the composite. The electrochemical analysis revealed enhanced charge-carrier number density and increased charge-carrier lifetime in the composite as a result of the presence of both silver and cobalt ions in the lattice. Further this enhanced charge-carrier separation of the composites was established through photocatalysis of Bisphenol-A under both solar and LED light. Charge-trapping study indicated *O2- and *OH as the major radicals involved and Z-scheme as the predominant charge transfer pathway for generation of these reactive oxygen species.

Double Z-scheme Co3O4/Bi4O7/Bi2O3 composite activated peroxymonosulfate to efficiently degrade tetracycline under visible light.

Co3O4/Bi4O7/Bi2O3 (CBB) composites were prepared, in which Co3O4 was synthesized from Co-MOF as precursor. The peroxymonosulfate (PMS) activated by CBB catalyst under visible light was used to degrade tetracycline (TC). Owing to the synergistic effect of photocatalysis and PMS activation, 98.4% of TC was removed within 60min. The optimal loading of Co3O4 was determined, and the influence of PMS dosage, initial pH, and disturbing anions on the degradation effect were investigated. The "CBB + Vis + PMS" system showed good reusability, and the degradation was only reduced by 1.7% after 5 cycles. This system also had a good degradation of other five pollutants. The quenching experiment showed that holes (h+), superoxide radicals (·O2-), and singlet oxygen (1O2) were the main active species. The degradation products of TC were determined by liquid chromatography-mass spectrometry, and the degradation pathway was proposed. Finally, a double Z-scheme degradation mechanism was proposed in the "CBB + Vis + PMS" system. The peroxymonosulfate activated by CBB under visible light to degrade organic pollutants has widespread application prospects in environmental remediation.

Constructing Co3O4/La2Ti2O7 p-n Heterojunction for the Enhancement of Photocatalytic Hydrogen Evolution.

Layered perovskite-type semiconductor La2Ti2O7 has attracted lots of attention in photocatalytic hydrogen evolution, due to the suitable energy band position for water splitting, high specific surface area, and excellent physicochemical stability. However, the narrow light absorption range and the low separation efficiency of photogenerated carriers limit its photocatalytic activity. Herein, plate-like La2Ti2O7 with uniform crystal morphology was synthesized in molten NaCl salt. A p-n heterojunction was then constructed through the in situ hydrothermal growth of p-type Co3O4 nanoparticles on the surface of n-type plate-like La2Ti2O7. The effects of Co3O4 loading on photocatalytic hydrogen evolution performance were investigated in detail. The results demonstrate that composite Co3O4/La2Ti2O7 possesses much better photocatalytic activity than the pure component. The composite photocatalyst with 1 wt% Co3O4 exhibits the highest hydrogen evolution rate of 79.73 μmol·g−1·h−1 and a good cycling stability. The photoelectrochemistry characterizations illustrate that the improvement of photocatalytic activity is mainly attributed to both the enhanced light absorption from the Co3O4 ornament and the rapid separation of photogenerated electron-hole pairs driven by the built-in electric field close to the p-n heterojunction. The results may provide further insights into the design of high-efficiency La2Ti2O7-based heterojunctions for photocatalytic hydrogen evolution.