Highest H2 Production Rate Research Articles

P‐Type Boron‐Doped Monolayer Graphene with Tunable Bandgap for Enhanced Photocatalytic H2 Evolution under Visible‐Light Irradiation

AbstractGraphene‐based materials are considered as one of the promising photocatalysts for hydrogen production from solar‐driven water splitting yet subject to zero bandgap limitation. Here, we report an efficient one‐step pyrolysis for preparing p‐type boron‐doped monolayer graphene. Through varying the dopant content, the bandgap of the boron‐doped graphene can be tuned. Moreover, a p‐type conductivity behavior of the boron‐doped monolayer graphene is demonstrated by the four‐probe measurement and Hall effect measurement. The boron‐doped graphene can service as an efficient semiconductor photocatalyst for hydrogen production from water splitting under visible‐light irradiation. The optimized boron‐doped graphene can deliver a high H2 production rate of 219.3 μmol h−1 g−1 without any cocatalyst. The photocatalyst can be recycled at least four times without obvious activity decay and maintain high H2 production rate of 215.3 μmol h−1 g−1 after 60 h reaction, indicative of excellent stability. This work may open up a new avenue for fabrication of new photocatalysts based on p‐type boron‐doped monolayer graphene.

Ultrasonic-microwave assisted synthesis of GO/g-C3N4 composites for efficient photocatalytic H2 evolution

There has been increasing interest in the study of photocatalysis technology application in hydrogen production by splitting water because of environmental pollution and energy utilization. In this study, a high efficiency of the photocatalytic H2 production was achieved via graphene oxide (GO) and graphitic carbon nitride (g-C3N4) composite photocatalysts (GO/g-C3N4). The GO/g-C3N4 photocatalysts possessed enhanced activities for hydrogen production than pure g-C3N4 under visible light irradiation. The structural and optical properties of all the synthesized photocatalysts were successfully characterized by XRD, FTIR, XPS, UV–vis spectra, TEM, SEM, N2 adsorption-desorption and photoluminescence spectra techniques. Experimental results indicated that GO/g-C3N4 photocatalysts can reach a high H2-production rate of 224.6 μmol/h (nearly 12 times of that obtained from pure g-C3N4) at GO content of 0.5 wt % and Pt 1 wt % under visible light irradiation. The enhanced photocatalytic activity of GO/g-C3N4 is ascribed to the ability of GO in accepting and transporting electrons from excited g-C3N4, which promotes the charge separation. This work highlights that the affordable and abundant carbon material can be a good candidate for an electron attracting collector and transporter to efficiently lengthen the lifetime of the photogenerated charge carriers in the field of photocatalytic hydrogen production.

Ultra-small cobalt nanocrystals embedded in 2D-MoS2 nano-sheets as efficient co-catalyst for solar-driven hydrogen production: Study of evolution rate dependence on cobalt nanocrystal size

2D-MoS2 nanostructures are attractive co-catalysts for photocatalytic hydrogen evolution due to their suitable water reduction potentials and high stability. However, the catalytic activity of MoS2 is greatly limited by the catalytically inert basal planes. Doping of transition-metal ions into MoS2 structure is an effective way to activating the basal planes. To this end, the formation of size-controlled metal nanocrystals with clean surface and mono dispersed nature is a current challenge. Here we utilized pulsed laser ablation in liquid approach to generate high purity size controlled cobalt nanocrystal by adjusting the laser fluences and systematically evaluate the effect of cobalt nanocrystals size and concentration on MoS2 to activate the basal planes. A set of Co-MoS2/CdS nanorods with different cobalt size were examined, and an optimal cobalt size of 3.1 nm was obtained. The optimized CdS/Co-MoS2 nanocomposite showed a very high H2 production rate (275 mmol h−1 g−1) with outstanding stability. To the best of our knowledge, this is the best performance reported for CdS/MoS2 based nanocomposites. The remarkable hydrogen evolution rate and stability may be due to reduced recombination rate and greatly increased density of catalytic active sites which is determined by photoluminescence and impedance spectroscopy. Finally, we believe that the strategies applied in the present study to form robust photocatalysts and its utilization in solar driven hydrogen production would inspire the development of other low-cost photocatalysts for renewable fuel production.

Phase controlled synthesis and the phase dependent photo-and electrocatalysis of CdS@CoMo2S4/MoS2 catalyst for HER

Herein we report a heterostructure with ultrathin nanosheets of Co-doped molybdenum sulfide on CdS nanorod array (donated as CdS@CoMo2S4/MoS2) by hydrothermal synthesis. Firstly, elemental Co doping MoS2 (CoMo2S4) delivers the double benefits of increased active sites and enhanced conductivity. Secondly, the structural characteristics maximally exposes the MoS2 edges and enlarges interfacial contact area between the composite catalyst and electrolyte, as well as the efficient interfacial charge transfer. The ratio of CoMo2S4/MoS2 in CdS@CoMo2S4/MoS2 plays a crucial role for the enhanced photo-assistant electrocatalytic hydrogen evolution reaction (HER). We can tune the ratio of CoMo2S4/MoS2 by controlling the preparation time or the ratio of precursor of Co/Mo. The catalyst with predominant MoS2 phase shows superior photocatalytic HER performance with a high H2 production rate of 46.60 μmol mg−1 h−1. Meanwhile, the catalyst with predominant CoMo2S4 phase exhibits not only relatively low overpotential of 172 mV at 10 mA cm−2, which outperforms most values that have been reported on catalyst supported on ITO substrate, but also possesses H2 production rate of 23.47 μmol mg−1 h−1. The superior photo-assistant electrocatalytic HER activity results from the synergistically structural and electronic modulations, as well as the proper energy band alignment between MoS2 and CdS. This investigation could provide an approach to integrate the electro- and photocatalytic activities for HER, especially the photo responding behaviour at a bias potential which is meaningful to produce H2 for actual application.

CuO@NiO core-shell nanoparticles decorated anatase TiO2 nanospheres for enhanced photocatalytic hydrogen production

Core-shell structured co-catalyst has been created much attention in photocatalytic hydrogen production due to their efficient electron-hole pair separation, suppression of surface back reaction and long term stability. Here, we report the preparation of CuO@NiO hierarchical nanostructures as a co-catalyst deposited on TiO2 nanospheres for enhanced photocatalytic hydrogen generation. The formation of ultrathin NiO shell over the CuO core was confirmed by TEM analysis. Fabricated core-shell nanostructured CuO@NiO over TiO2 nanospheres was studied for hydrogen evolution under the direct solar light and it showed a high rate of H2 production of 26.1 mmol. h−1. g−1cat. It was scrutinized that the rate of hydrogen production was improved with shell thickness and co-catalyst loading. Systematic investigation on CuO@NiO co-catalyst loading, pH of the medium and glycerol concentration for augmented H2 production. The recorded rate of hydrogen production is almost six folds greater than that of pristine TiO2. In the view of largescale synthesis for alternative energy storage applications, the composited photocatalyst was made of by simple mixing method, which could be scaled up without any loss in photocatalytic activity. Further, the stability test of photocatalyst for continuous use found that 82% of initial photocatalytic activity is retained even after three days.

Anode modified by BiFeO 3 and application in resourceful treatment of salty organic wastewater

The Ni foil or fluorine-doped SnO2 transparent conductive glass substrates modified by BiFeO3 film with a different atomic ratio of Bi to Fe were prepared by the method of spin coating-calcination at a different temperature. Coupling photo-catalysis with electro-catalysis, resourceful treatment of salty organic wastewater containing methyl orange and cadmium ion was proposed and experimentally achieved. Under visible light irradiation, the highest H2-production rate (5.46 ml/h cm2), degradation efficiency of methyl orange (51.6%), and the recovery precipitation weight of cadmium hydroxide (0.1846 g) were obtained with Ni foil modified by BiFeO3 (Bi:Fe = 1.10:1.00) film at 550°C of calcination. X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy, scanning electron microscopy, and the resourceful treatment test of salty organic wastewater were used to characterise the catalyst film.

Novel photocatalyst incorporating Ni-Co layered double hydroxides with P-doped CdS for enhancing photocatalytic activity towards hydrogen evolution

Designing durable and highly active photocatalysts for hydrogen evolution via water splitting is still very challenging. Novel NiCo-LDH/P-CdS hybrid photocatalysts are fabricated by combining strategies of P-doping and in-situ loading of NiCo-LDH. P-doping creates a mid-gap at the bottom of the conduction band of CdS, which facilitates to prolong the life-time of the photo-induced electrons. Subsequently, the in-situ loading of NiCo-LDH is able to form heterojunctions between NiCo-LDH and P-CdS that not only promote the separation efficiency of carriers, but also effectively reduce the light corrosion phenomenon commonly observed in CdS. The as-prepared 2 mol% NiCo-LDH/40 wt% P-CdS sample shows a high visible-light catalytic H2 production rate of 8.665 mmol·h−1 g−1, which is 45 times higher than pure CdS. The apparent quantum yield is determined to be 14.0% at 420 nm monochromatic light. Based on the calculation of density function theory (DFT), the rational photocatalytic mechanism has been proposed and is well consistent with the experimental results. Our study not only demonstrates a facile, eco-friendly and scalable strategy to synthesize highly efficient photocatalysts, but also provides a new viewpoint of the rational design and synthesis of advanced photocatalysts by harnessing the strong synergistic effects through simultaneously tuning and optimizing the electronic structure and surface.

Hierarchical NiO@N-Doped Carbon Microspheres with Ultrathin Nanosheet Subunits as Excellent Photocatalysts for Hydrogen Evolution.

Achieving highly efficient hierarchical photocatalysts for hydrogen evolution is always challenging. Herein, hierarchical mesoporous NiO@N-doped carbon microspheres (HNINC) are successfully fabricated with ultrathin nanosheet subunits as high-performance photocatalysts for hydrogen evolution. The unique architecture of N-doped carbon layers and hierarchical mesoporous structures from HNINC could effectively facilitate the separation and transfer of photo-induced electron-hole pairs and afford rich active sites for photocatalytic reactions, leading to a significantly higher H2 production rate than NiO deposited with platinum. Density functional theory calculations reveal that the migration path of the photo-generated electron transfer is from Ni 3d and O 2p hybrid states of NiO to the C 2p state of graphite, while the photo-generated holes locate at Ni 4s and Ni 4p hybrid states of NiO, which is beneficial to improve the separation of photo-generated electron-hole pairs. Gibbs free energy of the intermediate state for hydrogen evolution reaction is calculated to provide a fundamental understanding of the high H2 production rate of HNINC. This research sheds light on developing novel photocatalysts for efficient hydrogen evolution.

Loading AgCl@Ag on phosphotungstic acid modified macrocyclic coordination compound: Z-scheme photocatalyst for persistent pollutant degradation and hydrogen evolution

In this work, Z-scheme photocatalysts of (CuC10H26N6)3(PW12O40)2/AgCl@Ag were designed and realized for effective removal of solvable and insolvable persistent organic pollutants and hydrogen evolution under simulated sunlight. The catalysts were synthesized via a simple hydrothermal-chemical co-precipitation method. Excellent photocatalytic abilities are demonstrated in degradations of persistent pollutant 2,4-Dinitrophenol (DNP) and tetracycline (TC) under simulated sunlight, as well as a high H2 production rate of 19.28 μ mol g−1 h−1. Through structural, morphological, radical, and electrochemical determinations, the photocatalytic mechanism was studied, and attributed to effective separations of charge carriers between the heterojunctional counterparts of (CuC10H26N6)3(PW12O40)2 and AgCl@Ag.

Carbon quantum dots bridged TiO2 and Cd0.5Zn0.5S film as solid-state Z-scheme photocatalyst with enhanced H2 evolution activity

Abstract Traditional type II heterojunction photocatalyst usually has excellent activities due to the improved charge transfer between the matched band structures of each component, but this is also accompanied by reducing the oxidation–reduction capability of electrons and holes. Z-scheme system is demonstrated to be effective on maximizing the advantages of each photocatalyst. In this work, a novel Z-scheme heterojunction photocatalyst containing TiO2 nanofilm, Carbon Quantum Dots (CQDs) and Cd0.5Zn0.5S (CZS) nanoparticles (CZS/C/TiO2 nanofilm) was fabricated by hydrothermal method and an in situ reflux reaction process. The existence of CQDs results in a direct combination of electrons and holes from the CB of TiO2 and VB of Cd0.5Zn0.5S, and retains the active electron and holes in this system. Besides, it also benefits from the excellent optical absorption and prolonging electron lifetime, the ternary system shows excellent activity during photocatalytic water splitting with a high H2 production rate of 38.74 mmol·h − 1·m − 2, which is 3.4 and 1.5 times higher than that of pure TiO2 and CZS/TiO2 type II heterojunction without CQDs. In addition, CQDs bridged semiconductors as all solid-state Z-scheme heterojunction exhibit good stability and reusability.

In situ synthesis of ternary Zn0.5Cd0.5S (0D)/RGO (2D)/g-C3N4 (2D) heterostructures with efficient photocatalytic H2 generation activity

In this work, a novel ternary composite photocatalytic material was constructed by in-situ deposition of 0D Zn0.5Cd0.5S nanoparticles onto the 2D g-C3N4 and reduced graphene oxide (RGO) surfaces via a simple one-pot hydrothermal reaction. Through optimizing of the g-C3N4 component proportion, Zn0.5Cd0.5S heterostructure decorated with 3 wt% g-C3N4 nanosheets (Zn0.5Cd0.5S/g-C3N4) displayed a high H2-production rate of 4.956 mmol g−1h−1, which was 2.73 times higher than that of pure Zn0.5Cd0.5S nanoparticles. Additionally, when 1 wt% RGO was further introduced to the binary Zn0.5Cd0.5S/g-C3N4 heterostructure, the obtained ternary Zn0.5Cd0.5S (0D)/g-C3N4 (2D)/RGO (2D) composite catalyst exhibited the highest photocatalytic H2-production activity, whose H2-production rate was 5.41 times higher than that of pure Zn0.5Cd0.5S nanoparticles. The excellent activity of the ternary Zn0.5Cd0.5S/g-C3N4/RGO catalyst is associated with the cooperative effects of Zn0.5Cd0.5S nanoparticles, RGO and g-C3N4 nanosheets, which not only extend the light absorption range and intensity, but also reduce the overpotential for H2-production and dramatically improve the charge mobility and separation, thus boosting the H2-evolution rate over the ternary composite photocatalyst.

Structural, optical, and photocatalytic properties of Cd1−xS:Lax nanoparticles for optoelectronic applications

Cd1−xS:Lax nanoparticles with varying La and Cd concentrations have been prepared by microemulsion technique in the presence of cationic surfactant cetyl trimethyl ammonium bromide (CTAB). The structural phase for lanthanum-doped cadmium sulfide nanoparticles was investigated using X-ray diffraction revealing a cubic zinc blende structure for x = 0.0–0.06, while the hexagonal structure was obtained for higher La contents. The size of the nanoparticles was observed using field-emission scanning electron (FE-SEM) and transmission electron microscopy (TEM) and nanoparticles were found to exhibit a spherically symmetric shape. Energy-dispersive X-ray spectroscopy (EDX) was performed to analyze the composition of constituent elements. The measurements of photocatalytic hydrogen production indicated that La-doped CdS nanoparticles exhibit high H2-production rate as compared to that by the pure CdS. Diffuse UV–visible and photoluminescence spectra elucidated that bandgap varies inversely with the particle size; bandgap improves as particles size reduces for CdS with low La concentrations (~ 6%), in contrast, for higher La concentrations (8% and 10%) bandgap decays as the particle size improves. We believe that this work enriches the theory on La-doping CdS system and provides comprehensive guidance for the application of effective photocatalytic degradation.

Evaluation of process performance on biohydrogen production in continuous fixed bed reactor (C-FBR) using acid algae hydrolysate (AAH) as feedstock

In this study, a novel inoculation method to mitigate the inhibition of 5-hydroxymethylfurfural (5-HMF) is proposed. Acid algae hydrolysate containing 1.5 g 5-HMF/L and 15 g hexose/L hexose was fed to a continuous fixed bed reactor (C-FBR) partially packed with hybrid-immobilized beads. The inoculation method enabled a high rate of H2 production, due to the reduction of 5-HMF inhibition and enhanced biofilm formation. Maximum hydrogen production was achieved at a hydraulic retention time of 6 h with a hydrogen production rate (HPR) of 20.0 ± 3.3 L H2/L-d and a hydrogen yield (HY) of 2.3 ± 0.4 mol H2/mol hexose added. Butyrate and acetate were the major soluble metabolic products released during fermentation. Quantitative real-time polymerase chain reaction analysis revealed that Clostridium butyricum comprised 94.3% of the total bacteria, which was attributed to the high rate of biohydrogen production.

Wall-Mesoporous Graphitic Carbon Nitride Nanotubes for Efficient Photocatalytic Hydrogen Evolution.

Graphitic carbon nitride (g-CN) has attracted tremendous attention as visible-light photocatalyst. However, for further improving the catalytic activity, multilevel and hierarchical nanostructuring of g-CN is highly desirable to effectively expose active sites and facilitate separation and migration of photoexciteded charge carriers for largely enhanced photocatalytic behavior. Here, we prepare wall-mesoporous graphitic carbon nitride nanotubes (g-CNNTs) by in situ annealing of urea microrod arrays preformed in virtue of a vertical gradient freeze growth (VGFG) method. Benefiting from the distinctive structural features, the hierarchical g-CNNTs exhibit a high photocatalytic H2 production rate of 8789 μmol h-1 g-1 with an excellent apparent quantum yield of 6.3 % under visible-light irradiation and long-term cycling stability. This work provides a facile and eco-friendly strategy to prepare a new type of carbon nitride-based nanostructural material for photocatalysis and environmental remediation.

Perovskite Oxide LaNiO3 Nanoparticles for Boosting H2 Evolution over Commercial CdS with Visible Light.

LaNiO3 /CdS heterojunction photocatalysts are constructed by compositing LaNiO3 nanoparticles with commercially available CdS, and are used for efficient photocatalytic splitting of H2 O with visible light. The LaNiO3 /CdS hybrids are characterized systematically using a series of physicochemical techniques. The photocatalytic activity of the perovskite hybrids is examined by H2 evolution with Na2 S-NaSO3 as the hole scavenger. The optimized LaNiO3 /CdS sample without the assistance of any cocatalyst (e.g., Pt) delivers a high H2 production rate of 74 μmol h-1 (e.g., 3700 μmol h-1 g-1 ), which is substantially superior to the individual LaNiO3 and CdS. Besides, the composite photocatalyst also manifests high stability. The greatly improved H2 production performance of LaNiO3 /CdS is attributed to the facilitated separation and transport of photoinduced charge carriers, as evidenced by photoelectrochemical (PEC) analyses, such as photoluminscence spectroscopy, transient photocurrent responses, and electrochemical impedance spectroscopy. Moreover, a probable photocatalytic mechanism of the H2 evolution reaction is proposed on the basis of the results of the catalysis evaluation and PEC tests.

Heterostructured SnS2/SnO2 nanotubes with enhanced charge separation and excellent photocatalytic hydrogen production

SnO2, a promising candidate for photocatalytic water splitting, displays poor activity due to insufficient light utilization and rapid electron-hole recombination of charge carriers. Herein, one-dimensional heterostructures of SnO2/SnS2 nanotubes was designed and synthesized through a facile electrospinning followed by vulcanized method. The unique heterostructured SnO2/SnS2 could simultaneously promote photocarrier transport and suppress charge recombination through the uniquely coupled SnO2/SnS2 heterogeneous interface. Additionally, the optimized type-II heterostructure could also improve light absorption and weak the barrier of photocharge transfer. As a result, the SnO2/SnS2 exhibited excellent photocatalytic H2 evolution performance under simulated light irradiation with high H2 production rate of 50 μmol h−1 without the use of any noble metal co-catalyst, which is 4.2 times higher than that of pure SnO2 under the same condition.

Earth-abundant transition metal oxides with extraordinary reversible oxygen exchange capacity for efficient thermochemical synthesis of solar fuels

Efficient storage of solar and wind power is one of the most challenging tasks still limiting the utilization of the prime but intermittent renewable energy sources. The direct storage of concentrated solar power in renewable fuels via thermochemical splitting of water and carbon dioxide on a redox material is a scalable approach with up to 54% solar-to-fuel conversion efficiency. Despite progress, the search for earth-abundant materials that can provide and maintain high H2 and CO production rates over long period of high-temperature cycles continues. Here, we report a strategy to unlock the use of manganese, the 12th most abundant element in the Earth's crust, for thermochemical synthesis of solar fuels, achieving superior thermochemical stability, oxygen exchange capacity, and up to seven times higher mass-specific H2 and CO yield than cerium dioxide. We observe that incorporation of a small fraction of cerium ions in the manganese (II,III) oxide crystal lattice drastically increases its oxygen ion mobility, allowing its reduction from oxide to carbide during methane partial oxidation with simultaneous Ce exsolution. High CO2 and H2O splitting rates are achieved by re-oxidation of the carbide to manganese (II) oxide with simultaneous reincorporation of the cerium ions. We demonstrate that the oxide to carbide reaction is highly reversible achieving remarkable CO2 splitting rates over 100 thermochemical cycles of methane partial oxidation and CO2 splitting, and preserving the initial oxygen exchange capacity of 0.65 molOmolMn−1 and 89% of the fuel production rates. Due to this extraordinarily high reversible oxygen exchange capacity, the 3% Ce-doped manganese oxide achieves an average mass-specific CO yield for CO2 splitting of 17.72 mmolCO g−1, which is significantly higher than that previously achieved in thermochemical redox cycles. More generally, these findings suggest that incorporation of small soluble amounts of cerium in earth-abundant transition metal oxides like manganese oxide is a powerful approach to enable solar thermochemical fuel synthesis.

Three-Dimensional CdS/Au Butterfly Wing Scales with Hierarchical Rib Structures for Plasmon-Enhanced Photocatalytic Hydrogen Production.

Localized surface plasmon resonance (LSPR) of plasmonic metals (e.g., Au) can help semiconductors improve their photocatalytic hydrogen (H2) production performance. However, an artificial synthesis of hierarchical plasmonic structures down to nanoscales is usually difficult. Here, we adopt the butterfly wing scales from Morpho didius to fabricate three-dimensional (3D) CdS/Au butterfly wing scales for plasmonic photocatalysis. The as-prepared materials well-inherit the pristine hierarchical biostructures. The 3D CdS/Au butterfly wing scales exhibit a high H2 production rate (221.8 μmol·h-1 within 420-780 nm), showing a 241-fold increase over the CdS butterfly wing scales. This is attributed to the effective potentiation effect of LSPR introduced by multilayer metallic rib structures and a good interface bonding state between Au and CdS nanoparticles. Thus, our study provides a relatively simple method to learn from nature and inspiration for preparing highly efficient plasmonic photocatalysts.

Hierarchical Honeycomb Br-, N-Codoped TiO2 with Enhanced Visible-Light Photocatalytic H2 Production.

The halogen elements modification strategy of TiO2 encounters a bottleneck in visible-light H2 production. Herein, we have for the first time reported a hierarchical honeycomb Br-, N-codoped anatase TiO2 catalyst (HM-Br,N/TiO2) with enhanced visible-light photocatalytic H2 production. During the synthesizing process, large amounts of meso-macroporous channels and TiO2 nanosheets were fabricated in massive TiO2 automatically, constructing the hierarchical honeycomb structure with large specific surface area (464 m2 g-1). cetyl trimethylammonium bromide and melamine played a key role in constructing the meso-macroporous channels. Additionally, HM-Br,N/TiO2 showed a high visible-light H2 production rate of 2247 μmol h-1 g-1, which is far more higher than single Br- or N-doped TiO2 (0 or 63 μmol h-1 g-1, respectively), thereby demonstrating the excellent synergistic effects of Br and N elements in H2 evolution. In HM-Br,N/TiO2 catalytic system, the codoped Br-N atoms could reduce the band gap of TiO2 to 2.88 eV and the holes on acceptor levels (N acceptor) can passivate the electrons on donor levels (Br donor), thereby preventing charge carriers recombination significantly. Furthermore, the proposed HM-Br,N/TiO2 fabrication strategy had a wide range of choices for N source (e.g., melamine, urea, and dicyandiamide) and it can be applied to other TiO2 materials (e.g., P25) as well, thereby implying its great potential application in visible-light H2 production. Finally, on the basis of experimental results, a possible photocatalytic H2 production mechanism for HM-Br,N/TiO2 was proposed.

The synthesis of ZnO/SrTiO3 composite for high-efficiency photocatalytic hydrogen and electricity conversion

Heterogeneous ZnO–SrTiO3 nanocomposites were synthesized via a facile hydrothermal method. The highest H2 production rate, 1317.44 μmol g−1 within 5 h under solar-light irradiation was achieved for the Zn/Sr ratio of 9:1 of the ZnO–SrTiO3. More interestingly though the ZnO–SrTiO3 is a semiconducting system, it could be used as an electrolyte in the low temperature solid oxide fuel cell without electronic conducting short circuiting problem. This device displayed an open circuit voltage of 1.14 V and reached the maximum power density of 564 mW cm−2 at 550 °C. These results are attributed to the enhanced separation of the charge-hole pairs by the heterogeneous structure of ZnO–SrTiO3 nanocomposites, which possess obvious both heterogeneously ionic and semiconduction. This new discovery indicates a good promising candidate for both solar and hydrogen energy conversions.