New energy storage and conversion systems require large-scale, cost-effective, good safety, high reliability, and high energy density. This study demonstrates a low-cost and safe aqueous rechargeable lithium-nickel (Li-Ni) battery with solid state Ni(OH)2/NiOOH redox couple as cathode and hybrid electrolytes separated by a Li-ion-conductive solid electrolyte layer. The proposed aqueous rechargeable Li-Ni battery exhibits an approximately open-circuit potential of 3.5 V, outperforming the theoretic stable window of water 1.23 V, and its energy density can be 912.6 W h kg-1, which is much higher than that of state-of-the-art lithium ion batteries. The use of a solid-state redox couple as cathode with a metallic lithium anode provides another postlithium chemistry for practical energy storage and conversion.

•High quality, excellent crystallinity CH3NH3PbI3 perovskite film was synthesized through slicing and restacking single crystal.•The process enables a sustainable solvent utilization and facile one-step deposition method.•Reveal an in-situ fabrication of 2D layered perovskite through intercalation.Owing to their high conversion efficiency and potentially cost-effective manufacturing, organic–inorganic lead halide perovskite solar cells (PSCs) have been dominant photovoltaic research topic in this decade. The photovoltaic performance of PSCs is highly dependent upon the quality of perovskite layer. In order to advance the deployment of PSCs, fabrication of high-quality perovskite film using a facile and sustainable process is essential. This study provides significant breakthrough in this direction. A novel fabrication process is demonstrated that allows slicing of 2D layers from single crystals and restacking them to fabricate high-quality perovskite film. The discovery that CH3NH2 can slice the 3D CH3NH3PbI3 perovskite crystal into 2D layered perovskite intermediates via intercalation process opens a new pathway for pursuing synthesis of a variety of photovoltaic materials. The 2D layered intermediate shows high solubility in acetonitrile (ACN) solvent, which is considered as a replacement for N, N-dimethylformamide (DMF) in order to enable sustainable processing. This solvent system enables fabrication of high-quality perovskite layer by one-step synthesis method. Based on this cost-effective sustainable synthesis approach, low temperature processed PSC was found to match the performance of PSC synthesized using high temperature process.Download high-res image (258KB)Download full-size image

A composite cathode including N-rGO with homogeneously dispersed perovskite La0.8Sr0.2Co0.8Fe0.2O3 on the surface is studied. Li–O2 batteries with LSCF@N-rGO cathode show better performance than those with LSCF-SP or N-rGO cathode. EIS and morphology analysis indicate that LSCF is beneficial to remold the shape of Li2O2 and catalyze the decomposition of Li2O2.

•Nanostructured LSCN-GDC oxygen electrodes are prepared by impregnation for SOEC.•LSCN-GDC oxygen electrodes present great enhancement for OER.•Nanoparticle LSCN on GDC scaffold can improve the active reaction sites.•Hydrogen production rate of 484 mL cm−2h−1 at 750 °C is obtained on the electrode.Nanostructured La0.8Sr0.2Co0.8Ni0.2O3-δ (LSCN) based Gd2O3-doped CeO2 (GDC) oxygen electrodes are prepared by impregnation method for intermediate temperature solid oxide electrolysis cell (SOEC) for efficient hydrogen production. The microstructure features and the electrochemical performance of the impregnated LSCN-GDC oxygen electrodes with various LSCN loadings are evaluated and investigated. Electrochemical tests show that the impregnated LSCN-GDC oxygen electrodes present great enhancement of oxygen evolution performance, due to the good nanoparticle LSCN dispersion on the GDC scaffold surface to maximize the active reaction sites. The cell with 30 wt% LSCN loaded LSCN-GDC as the oxygen electrode presents a polarization resistance of 0.072 Ω cm2 at 800 °C with 60 vol% absolute humidity (AH), only about half of that for the screen-printed LSCN electrode. The hydrogen production rate is 484 mL cm−2 h−1 at 750 °C at 1.5 V with 60 vol%AH. For stability test in galvanostatic SOEC operation up to 100 h, the solution impregnated cell shows a very stable performance without obvious degradation.

Non-aqueous lithium air batteries with high energy density have been regarded to be the most attractive contender in the future energy storage techniques. Herein, the perovskite La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) nanoparticles are studied as the cathode catalyst for non-aqueous lithium air batteries. The results confirm that nanostructured LSCF exhibits admirable electrochemical activity and can effectively reduce the overpotential. Batteries with LSCF catalyst can increase the discharge capacity from 9678 mAh g−1 to 13979 mAh g−1 and improve the cycle stability from 10 cycles to 20 cycles at 200 mA g−1. The study reveals that the formation and decomposition processes of Li2O2 can be effectively promoted by the introduction of LSCF nanoparticles. The possible catalytic mechanism of LSCF in reducing overpotential is also proposed.

The high overpotentials of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the air cathode are still big challenge to be overcome for the high performance non-aqueous lithium-air batteries (LABs), especially in ambient air. In this paper, dandelion-like NiCo2O4 hollow microspheres are prepared through a simple self-assembled hydrothermal process as cathode catalyst. The assembled LABs show relative high discharge potential in different oxygen partial pressure, and can deliver a reversible capacity of 8019 mAh·g−1 at the current density of 300 mA·g−1 with stable cycle performance for at least 40 times in ambient air. The excellent performance of NiCo2O4 cathode can be attributed to the dandelion hollow structure, together with the abundant oxygen vacancies, which would enhance the ORR and OER process. The study confirms the feasibility of dandelion-like NiCo2O4 hollow spheres as efficient cathode for the LABs in ambient air.

The air cathode is vital for lithium–oxygen batteries (LOBs) to achieve high performance, which will facilitate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) during the discharge and charge processes. In this paper, MnCo2O4 nanospheres prepared through the hydroxide co-precipitation method are investigated as an effective electrocatalyst for the ORR and OER in non-aqueous LOBs. The results show that a non-aqueous LOB with the electrocatalyst exhibits an excellent discharge capacity of 8518 mA h gcathode−1 with a narrow voltage gap of 0.85 V between the discharge and charge plateaus at a current density 100 mA gcathode−1, and can deliver cycling stability over 20 cycles. This study shows that MnCo2O4 nanospheres can be a promising cathode electrocatalyst in rechargeable lithium–oxygen batteries due to its enhanced catalytic activity towards the ORR and OER.

•Cu-MnCo2O4 coating for SUS 430 is evaluated in cathode atmosphere up to 2000 h.•MnCu0.5Co1.5O4 coating has ASR of 8.04 mΩ cm2 oxidized at 750 °C for 22 cycles.•MnCu0.5Co1.5O4 coating is stable at applied current 0.5 A cm−2 at 750 °C for 200 h.Spinel oxides with the general formula of MnCuxCo2−xO4 (x = 0.1, 0.3, 0.5, 0.7 respectively) are used as coating materials on the metallic interconnect SUS 430 alloy to reduce the cathodic performance degradation by Cr poisoning and the interfacial resistance to improve the surface stability. The effect of Cu doping at the B position of spinel on the electrical conductivity and coefficient of temperature expansion (CTE) is investigated to determine the oxidation behavior and effectiveness as a protective layer. The result confirms that MnCu0.5Co1.5O4 spinel shows highest electrical conductivity of 105.46 S cm−1 at 750 °C in air and an average CTE value of 12.27 × 10−6 K−1 at temperature range of 20–960 °C. MnCu0.5Co1.5O4 coating is stable enough after 2000 h cyclic oxidation at 750 °C. The growth of Cr2O3 and formation of MnCr2O4 in the scale layer are effectively suppressed by the presence of MnCu0.5Co1.5O4 coating. The oxidation kinetics obeys the parabolic law with a rate constant as low as 2.76 × 10−15 g2 cm−4·s−1 and the ASR contributed by the oxide scale is 8.04 mΩ cm2 at 750 °C. The research indicates that MnCu0.5Co1.5O4 is a promising coating material for metallic interconnects of the intermediate temperature solid oxide fuel cells.

A lanthanum titanate (La2Ti2O7) and indium oxide (In2O3) heterojunction nanocomposite is synthesized by a solvothermal method. The crystal phase, morphology, optical absorption activity and chemical composition of the In2O3/La2Ti2O7 heterojunction nanocomposites are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results reveal that the In2O3 nanoparticles are uniformly dispersed on the surface of the La2Ti2O7 nanosheets with good adhesion. The In2O3/La2Ti2O7 nanocomposite with a molar ratio of 1.5:1 exhibits the highest H2 production rate when used in photocatalytic water splitting, improved by 29.62 and 6.43 times relative to pure In2O3 and La2Ti2O7, respectively. The enhanced photocatalytic H2 production rate can be ascribed to the formation of the heterojunction structure, which results from the homogeneous dispersion of In2O3 nanoparticles on La2Ti2O7 nanosheets. The configuration of the In2O3/La2Ti2O7 heterojunction nanocomposite photocatalyst can promote the fast separation of photogenerated carriers in space and improve the rate of water-splitting to form H2.

•(Fe, Cr)-codoped La2Ti2O7 can increase the degree of narrowing of band gap.•(Fe, Cr)-codoped La2Ti2O7 exhibits excellent photocatalytic H2 production of 360.203 μmol g−1 h−1.•The calcination temperature and doping concentration are crucial for the photocatalyst.Highly visible-light response (Fe, Cr)-codoped La2Ti2O7 photocatalysts are synthesized by sol–gel process. The crystal phase, morphology and optical absorption activity of the samples are characterized by X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy, and UV–vis diffuse reflectance spectra. The results reveal that the calcination temperature and dopant concentration have strong influence on the phase structures, crystallinity and morphology. The UV–vis diffuse reflectance spectra indicate that Fe and Cr ions codoping can extend optical absorption to the visible-light region and narrow the band gap obviously. The photocatalytic hydrogen and oxygen production activities are evaluated in CH3OH and AgNO3 aqueous solution under solar light irradiation. NiOx (0.5 wt%) loaded (Fe, Cr)-0.005-LTO-1150 shows the best photocatalytic H2 production activity with the productivity of 360.203 μmol g−1 h−1 and the apparent quantum efficiency of 2.44%, which suggests that the synergistic effect of Fe and Cr codoping is favorable to enhance the photocatalytic efficiency. The photocurrent of (Fe, Cr)-codoped La2Ti2O7 is more than two times of that for Fe-doped La2Ti2O7 photocatalyst. The efficient photocatalytic hydrogen production and the high photocurrent of (Fe, Cr)-0.005-LTO-1150 are originated from the optimized combination of the physical–chemical properties, the small band gap and the low recombination rate of photoelectron–holes.

In this paper, the electrocatalytic performance of cobaltite spinels for oxygen evolution reaction (OER) in alkaline electrolysis is studied. Cobaltites MxCo3-xO4 (M= Ni, Cu, Zn, Mn; x = 1 or 0.9) are synthesized by the coprecipitation method and characterized for the OER performance. Cyclic voltammetric measurement confirms that the cobaltites exhibit different redox characteristic for Co cation couples. NiCo2O4 and MnCo2O4 show the redox couple of Co(III)/Co(II) during OER, while for ZnCo2O4 and Cu0.9Co2.1O4 are Co(IV)/Co(III). OER measurement reveals that all these cobaltite spinel electrodes show better performance than metal Ni electrode. And ZnCo2O4 shows the best performance for OER with the highest current density of 205mAcm−2 at potential of 0.7 V. XPS result verifies that the cobaltites have the different surface Co cations distribution. The analysis discovers that the amount of the surface Co cations occupying the octahedral sites in spinel is crucial for OER performance.

•Formation of SrCoOx after current polarization was confirmed by XRD and XPS.•Polarization at high current density accelerates the performance degradation.•Agglomeration and coarsening contribute to the deterioration of cathodes.The performance stability and degradation mechanism of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathodes and LSCF impregnated Gd0.1Ce0.9O2−δ (LSCF-GDC) cathodes are investigated under solid oxide fuel cell operation conditions. LSCF and LSCF-GDC cathodes show initially performance improvement but degrade under cathodic polarization treatment at 750 °C for 120 h. The results confirm the grain growth and agglomeration of LSCF and in particular GDC-LSCF cathodes as well as the formation of SrCoOx particles on the surface of LSCF under cathodic polarization conditions. The direct observation of SrCoOx formation has been made possible on the surface of dense LSCF electrode plate on GDC electrolyte. The formation of SrCoOx is most likely due to the interaction between the segregated Sr and Co from LSCF lattice under polarization conditions. The formation of SrCoOx would contribute to the deterioration of the electrocatalytic activity of the LSCF-based electrodes for the O2 reduction in addition to the agglomeration and microstructure coarsening.

Dye-sensitized solar cells (DSSC) have received considerable attention owing to their low preparation cost and easy fabrication process. However, one of the drawbacks that limits the further application of DSSC is their poor stability, arising from the leakage and volatilization of the liquid organic solvent in the electrolyte. Therefore, to improve the long-term stability of DSSC, polymer gel electrolyte was studied to replace the conventional liquid electrolyte in this work. The results show that compared to liquid electrolyte, DSSC with polymer gel electrolyte has a smaller short-circuit current (Jsc), which decreases with the increase of the polymer gelator. Nevertheless, with the employment of the polymer gel electrolyte, there is a significant enhancement of open-circuit voltage (Voc), and it increases with the increase of the polymer gelator content. The highest Voc, up to 0.873 V, can be obtained for DSSC with a 30% polymer gelator content. The impact of the polymer gel electrolyte on the photovoltaic performance of DSSC, especially on Voc, was studied by analyzing the charge-transfer kinetics in the polymer gel electrolyte. Furthermore, the influence of the polymer gel electrolyte on the long-term stability of DSSC was also investigated.Keywords: charge recombination; long-term stability; mass transport; polymer gel electrolyte; Voc enhancement;

Dye-sensitized solar cell (DSSC) based on TiO2 nanowires/nanoparticles composite photoanode with SrO shell coating is studied. TiO2 nanowires are synthesized by hydrothermal treatment and the composite photoanodes are prepared through mixing various mass ratios of nanowires and nanoparticles. The result shows that the composite photoanode containing optimized TiO2 nanoparticles and nanowires can increase electron transfer efficiency. DSSC with PW10 (nanowires content is 10 wt%) photoanode shows a relative high conversion efficiency of 6.27% because of the synergistic role of the high specific area of nanoparticles and rapid electron transfer of nanowires. Furthermore, PW10 photoanode with SrO shell coating can increase the conversion efficiency to 6.91% due to the barrier role of the shell. The research confirms that such a novel photoanode structure can suppress the electrons recombination process and increase the conversion efficiency effectively.Highlights► TiO2 nanowire/nanoparticle composite photoanode with SrO shell is prepared. ► The composite photoanode PW10 obtains high conversion efficiency (η) of 6.27%. ► SrO shell on composite photoanode can further improve η to 6.91%.

Polymer electrolytes, acting as an ionic solid-state conducting phase, have been demonstrated as promising charge carrying mediators for energy storage devices. However, the large majority of polymer electrolyte studies are focused on cation transportation and little consideration has been given to the investigation of the anion transportation mechanism. In this study we focus on the individual ionic transportation mechanisms in polymer electrolytes for potential application in dye-sensitized solar cells (DSSCs). To explore the ionic transportation mechanism, polymer electrolytes with different ion concentrations were studied. The influence of ion concentration on the structure of the polymer electrolytes was elucidated using X-ray diffraction (XRD) and Raman spectroscopy. Additionally, the temperature and composition dependence of the ionic conductivity and restricted ion diffusion coefficient of the polymer electrolytes were studied to gain an insight into the ionic transportation mechanism. The behavior of the anion transportation was further discussed via the addition of I2 into the polymer electrolytes. The results imply that the disorder and flexibility of the polymer matrix are favorable for ionic transportation, and that mass transportation can be facilitated by increasing the I2 concentration in the polymer electrolyte, which could be applied in DSSCs.

•Performance and microstructure of nano-structured LSCF–GDC cathodes are studied in detail.•Agglomeration of infiltrated LSCF nanoparticles is responsible for the performance degradation.•Surface composition change could also contribute to the degradation in the electrochemical activity of the cathodes.•Addition of MgO or LNF phase effectively inhibit the agglomeration of LSCF nanoparticles.The performance degradation of composite cathodes of La0.6Sr0.4Co0.2Fe0.8O3−δ and Gd-doped ceria (LSCF–GDC), prepared by impregnating the porous GDC scaffold with a nitrate solution containing La, Sr, Co and Fe in desired composition, is investigated at 750 °C and open circuit in air for 500 h. The performance of the impregnated LSCF–GDC composite cathodes deteriorates after testing at 750 °C for 500 h; the electrode polarization resistance (Rp) increases from 0.38 to 0.83 Ω cm2, and the electrode ohmic resistance (Ro) increases from 1.79 to 2.14 Ω cm2. The grain growth and coarsening of impregnated LSCF nanoparticles are responsible for the performance degradation of the cathodes. XPS analysis shows the enrichment of cobalt on the surface of the infiltrated LSCF–GDC cathodes and such surface segregation could also contribute to the degradation of the electrocatalytic activity of the cathodes. Introducing MgO and LaNi0.6Fe0.4O3 phases can effectively suppress the coarsening of LSCF nanoparticles and enhance the stability of the cathodes. However, the enhancing effect is related to the conductivity and electrocatalytic activity of the introduced phases.

Visible–light active (N, P)-codoped TiO2 (NP-TiO2) nanoparticles are prepared by one step hydrothermal method and characterized by XPS, XRD, SEM, FT-IR and UV–vis spectrum. Based on the XPS analysis, the chemical state of N in TiO2 is identified as N–Ti–O in the anatase TiO2 lattice, while P exists in a pentavalent-oxidation state (P5+) or as PO43- group coordinating in TiO2. The result confirms that the doping of phosphate would affect the crystallite size and structure of anatase. UV–vis spectra demonstrates that NP-TiO2 could shift the absorption edge of titania to the visible–light region effectively, which could increase the visible–light photocatalytic activity. The total degradation of methylene blue (MB) and rhodamine B (RhB) is significantly faster on NP-TiO2 samples than that on N-doped and NS-codoped TiO2 under visible–light irradiation.Highlights► (N, P)-codoped TiO2 powders are prepared by a one-step hydrothermal method. ► N doping results in the formation of O–Ti–N linkage in anatase. ► P exists in a pentavalent-oxidation state (P5+) or as PO43- group. ► The codoped samples show enhanced visible–light photocatalytic activity.

Composite cathodes of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and Y2O3 stabilized ZrO2 (YSZ) are fabricated by impregnating the porous YSZ scaffold pre-formed on YSZ electrolyte substrate with a solution containing La, Sr, Co and Fe in desired composition. The performance stability of the cathodes is evaluated in air at 750 °C for up to 120 h by electrochemical impedance spectroscopy under the condition of open circuit. An insignificant small amount of resistive phase SrZrO3 is formed at 800 °C during cathode preparation; however, its volume is not further increased at 750 °C for 120 h, as indicated by the XRD results. The cathode polarization resistance (Rp) increases from 0.17 to 0.30 Ωcm2 after the 120 h test mainly due to the increase of the low frequency polarization resistance (Rp2), which characterizes the low frequency processes in the reaction of oxygen reduction. The morphology change of the well connected LSCF particles to dispersive and flattened configuration accounts for the increase of the Rp2 and in turn the degradation of cathode performance.Highlights► The cathode is evaluated continuously at 750 °C for 120 h under open circuit. ► The degradation of LSCF + YSZ cathodes is mainly related to mass transfer process. ► Flattening of LSCF particles lead to the degradation of LSCF + YSZ cathodes.

(N, S)-codoped titania (TiO2) is synthesized by a simple template-free solvothermal method as photoanode for dye-sensitized solar cells (DSSCs). The results confirm that N and S have been doped into the lattice of anatase, which can enhance the visible-light absorbance and promote the electron transportation in TiO2. The prepared (N, S)-codoped TiO2 exhibits pure anatase phase mesoporous nanoparticles with average diameter of 60 nm. Mixing (N, S)-codoped TiO2 with Degussa P25 as photoanode results in the improvement of open-circuit voltage and short-circuit photocurrent density of DSSC. And the corresponding DSSC obtains a high conversion efficiency of 8.0%.Highlights► Mesoporous (N, S)-TiO2 nanoparticles are synthesized by a solvothermal method. ► (N, S)-codoped TiO2 can improve Voc and Jsc of DSSC. ► DSSC with hierarchical photoanode shows a high conversion efficiency of 8%.

Solution impregnated La0.8Sr0.2Co0.8Ni0.2O3 + Gd-doped CeO2 (LSCN + GDC) cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC) are prepared and their electrochemical properties are evaluated and compared with the conventional LSCN cathodes. The results indicate that the cathode performance can be enhanced by the presence of the nanosized microstructure produced with the solution impregnation method. It is determined that the amount of LSCN loading in the LSCN + GDC composite cathode needs to be higher than 35 wt% in order to achieve a performance superior to that of the conventional LSCN cathode. The optimum amount of LSCN loading is in the range of 45–55 wt% with an activation energy near 1.32 eV for oxygen reduction. At temperatures between 600 and 750 °C, the polarization resistance of the 55 wt% LSCN loaded LSCN + GDC cathode is in the range of 1.07 and 0.08 Ω cm2, which is only about one half of that for the conventional cathode.Highlights► Solution impregnated LSCN + GDC cathodes for SOFC were prepared and evaluated. ► The optimized LSCN loading is in the range of 45–55 wt%. ► At 600–750 °C, the cathode has a very low polarization resistance of 1.07–0.08 Ω cm2.

Nano-structured Pd-infiltrated YSZ cathodes (Pd + YSZ) are prepared by impregnation method and their electrocatalytic activity and reduction–oxidation behavior are investigated. It is observed that nano-sized PdO particles are uniformly distributed on the surface of the YSZ scaffold and decomposed at a temperature below 800 °C in air. Coexistence of Pd and PdO in the Pd + YSZ cathode is detected at temperatures between 650 and 750 °C. The polarization resistance RE of the Pd + YSZ cathode decreases continuously as oxygen partial pressure increases from 0.001 to 1 atm at 600 and 850 °C, whereas it reaches a minimum in the vicinity of 0.03 atm of oxygen partial pressure at 750 °C. In air with an oxygen partial pressure of 0.21 atm, the Pd + YSZ shows the lowest activation energy for the oxygen reduction reaction in the temperature range of 650 and 750 °C.

Electronic and optical properties of pure, N-doped, Fe-doped and (N, Fe)-codoped anatase TiO2 were evaluated, respectively, by using the density functional theory. The results indicate that the elemental doping narrows the band gap of TiO2 and realize its visible-light response activity; and incorporation of Fe into N-doped TiO2 further increases the photocatalytic activity under visible-light irradiation compared with that of the N-doped TiO2.Highlights► A first-principle studies the electronic and optical properties of (N, Fe)-codoped anatase TiO2. ► All the doped system can narrow the band gap and realize visible-light response of anatase. ► (N, Fe)-codoped anatase shows better visible-light photocatalytic activity than mono-doping system.

•TiO2/ZnO nanorod arrays are prepared as PEC photoanode for water splitting.•Hydrogenation enhances optical absorption and increase photogenerated carriers.•Hydrogenated TiO2/ZnO arrays are promising electrodes for PEC cells.Novel hydrogenated TiO2/ZnO heterojunction nanorod arrays as photoanodes for efficient photoelectrochemical cells are investigated in this paper. A facial solution coating method is used to prepare the heterojunction structure and then hydrogenated heterojunction is obtained by annealed in hydrogen atmosphere. The enhanced optical absorption is observed for the hydrogenated TiO2/ZnO heterojunction. The hydrogenated TiO2/ZnO heterojunction yields improved photocurrent density, which is higher than pure TiO2 nanorods and TiO2/ZnO heterojunction. The ability to gain excellent photoelectrochemical properties with hydrogenated TiO2/ZnO heterojunction nanorod arrays may provide a promising route for high performance photoelectrochemical cells.

A lanthanum titanate (La2Ti2O7) and indium oxide (In2O3) heterojunction nanocomposite is synthesized by a solvothermal method. The crystal phase, morphology, optical absorption activity and chemical composition of the In2O3/La2Ti2O7 heterojunction nanocomposites are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results reveal that the In2O3 nanoparticles are uniformly dispersed on the surface of the La2Ti2O7 nanosheets with good adhesion. The In2O3/La2Ti2O7 nanocomposite with a molar ratio of 1.5:1 exhibits the highest H2 production rate when used in photocatalytic water splitting, improved by 29.62 and 6.43 times relative to pure In2O3 and La2Ti2O7, respectively. The enhanced photocatalytic H2 production rate can be ascribed to the formation of the heterojunction structure, which results from the homogeneous dispersion of In2O3 nanoparticles on La2Ti2O7 nanosheets. The configuration of the In2O3/La2Ti2O7 heterojunction nanocomposite photocatalyst can promote the fast separation of photogenerated carriers in space and improve the rate of water-splitting to form H2.

A composite cathode including N-rGO with homogeneously dispersed perovskite La0.8Sr0.2Co0.8Fe0.2O3 on the surface is studied. Li–O2 batteries with LSCF@N-rGO cathode show better performance than those with LSCF-SP or N-rGO cathode. EIS and morphology analysis indicate that LSCF is beneficial to remold the shape of Li2O2 and catalyze the decomposition of Li2O2.