Realization of Long-Life Proton Battery by Layer Intercalatable Electrolyte.

Proton batteries have attracted increasing interests because of their potential for grid-scale energy storage with high safety and great low-temperature performances. However, their development is significantly retarded by electrolyte design due to free water corrosion. Herein, we report a layer intercalatable electrolyte (LIE) by introducing trimethyl phosphate (TMP) into traditional acidic electrolyte. Different from conventional role in batteries, the presence of TMP intriguingly achieves co-intercalation of solvent molecules into the interlayer of anode materials, enabling a new working mechanism for proton reactions. The electrode corrosion was also strongly retarded with expanded electrochemical stability window. The half-cell therefore showed an outstanding long-term cycling stability with 91.0 % capacity retention at 5 A g-1 after 5000 cycles. Furthermore, the assembled full batteries can even deliver an ultra-long lifetime with a capacity retention of 74.9 % for 2 months running at -20 °C. This work provides new opportunities for electrolyte design of aqueous batteries.

[Formation Potential of Secondary Organic Aerosols and Sources of Volatile Organic Compounds During an Air Pollution Episode in Autumn, Langfang].

A typical particulate matter pollution process occurred from October 9 to 17,2018,in Langfang,and 99 types of volatile organic compounds (VOCs) were monitored by using ZF-KU-1007. The characteristics of VOCs,formation potential of secondary organic aerosol (SOA),and source of VOCs were systematically analyzed. The results showed that the maximum concentration of PM2.5 was 198 µg·m-3 during the pollution process and was 2.64 times the National Ambient Air Quality Standard (GB 3095-2012). The average concentration of VOCs was 56.8×10-9,127.8×10-9,and 72.5×10-9 in the early,middle,and late stages of the pollution process,respectively,and the concentration of VOCs increased significantly in the middle stage. The formation potential of SOA was significantly positively correlated with PM2.5,and the contribution of aromatic hydrocarbon for SOA was larger and significantly correlated with the concentration of PM2.5. In the middle pollution stage,SOA increased,and the contribution ratio of aromatic hydrocarbon increased significantly. Conversely,the contribution of alkanes and olefin decreased significantly,which showed that aromatic hydrocarbons,namely benzene series,were the dominant species of SOA generation and had a great influence on the pollution process. Benzene,toluene,m-/p-xylene,o-xylene,and ethylbenzene and nonane,n-undecane,and methylcyclohexane were the priority control species in this pollution process. Solvent use source and motor vehicle emission source (gasoline and diesel vehicles) were the main sources affecting the concentration of VOCs during the autumn pollution process of Langfang,among which the contribution of gasoline vehicle emissions increased significantly in the middle pollution contribution and was the key control source.

Superstructure-Assisted Single-Atom Catalysis on Tungsten Carbides for Bifunctional Oxygen Reactions.

Single-atom catalysis (SAC) attracts wide interest for zinc-air batteries that require high-performance bifunctional electrocatalysts for oxygen reactions. However, catalyst design is still highly challenging because of the insufficient driving force for promoting multiple-electron transfer kinetics. Herein, we report a superstructure-assisted SAC on tungsten carbides for oxygen evolution and reduction reactions. In addition to the usual single atomic sites, strikingly, we reveal the presence of highly ordered Co superstructures in the interfacial region with tungsten carbides that induce internal strain and promote bifunctional catalysis. Theoretical calculations show that the combined effects from superstructures and single atoms strongly reduce the adsorption energy of intermediates and overpotential of both oxygen reactions. The catalyst therefore presented impressive bifunctional activity with an ultralow potential gap of 0.623 V and delivered a high power density of 188.5 mW cm-2 for assembled zinc-air batteries. This work opens up new opportunities for atomic catalysis.

Highly Crystalline Poly(heptazine imide)-Based Carbonaceous Anodes for Ultralong Lifespan and Low-Temperature Sodium-Ion Batteries.

Carbon nitrides with layered structures and scalable syntheses have emerged as potential anode choices for the commercialization of sodium-ion batteries. However, the low crystallinity of materials synthesized through traditional thermal condensation leads to insufficient conductivity and poor cycling stability, which significantly hamper their practical applications. Herein, a facile salt-covering method was proposed for the synthesis of highly ordered crystalline C3N4-based all-carbon nanocomposites. The sealing environment created by this strategy leads to the formation of poly(heptazine imide) (PHI), the crystalline phase of C3N4, with extended π-conjugation and a fully condensed nanosheet structure. Meanwhile, theoretical calculations reveal the high crystallinity of C3N4 significantly reduces the energy barrier for electron transition and enables the generation of efficient charge transfer channels at the heterogeneous interface between carbon and C3N4. Accordingly, such nanocomposites present ultrastable cycling performances over 5000 cycles, with a high reversible capacity of 245.1 mAh g-1 at 2 A g-1 delivered. More importantly, they also exhibit an outstanding low-temperature capacity of 196.6 mAh g-1 at -20 °C. This work offers opportunities for the energy storage use of C3N4 and provides some clues for developing long-life and high-capacity anodes operated under extreme conditions.

A Short-Range Ordered α-MoO3 with Modulated Interlayer Structure via Hydrogen Bond Chemistry for NH4 + Storage.

The layered orthorhombic molybdenum trioxide (α-MoO3) is a promising host material for NH4 + storage. But its electrochemical performances are still unsatisfactory due to the absence of fundamental understanding on the relationship between structure and property. Herein, NH4 + storage properties of α-MoO3 are elaborately studied. Electrochemistry together with ex situ physical characterizations uncover that irreversible H+/NH4 + co-intercalation in the initial cycle confines the electrochemically reactive domain to the near surface of α-MoO3 thus resulting in a low reversible NH4 + storage capacity. This issue can be resolved by decreasing ion diffusion pathway to construct short-range ordered α-MoO3 (SMO), which improves the specific capacity to 185 mAh g-1. SMO suffers from dissolution issue. In view of this the interlayer structure of SMO is reconstructed via hydrogen bond chemistry to reinforce the structural stability and it is discovered that the hydrogen bond network only with moderate intensity endows SMO with both high capacity and ability against dissolution. This work presents a new avenue to improve the NH4 + storage properties of α-MoO3 and highlights the important role of hydrogen bond intensity in optimizing electrochemical properties.

Characterization, Expression, and Functional Analysis of the Northern Snakehead (Channa argus) Hepcidin.

Hepcidin, an antimicrobial peptide (AMP), is a well-conserved molecule present in various species such as fish, amphibians, birds, reptiles, and mammals. It exhibits broad-spectrum antimicrobial activity and holds a significant role in the innate immune system of host organisms. The northern snakehead (Channa argus) has become a valuable freshwater fish in China and Asia. In this investigation, the cDNA encoding the hepcidin gene of northern snakehead was cloned and named caHep. The amino acid sequences and protein structure of caHep are similar to those of hepcidins from other fish. The eukaryotic expression product of the caHep gene showed broad-spectrum antibacterial activity. Scanning electron microscope analysis indicated that the caHep peptide inhibited bacterial growth by damaging their cell membranes. Lipopolysaccharide (LPS) injection induced significant expression of caHep, implying the involvement of caHep in the innate immune response of northern snakeheads. This investigation showed that the caHep peptide is potentially a robust antibacterial drug against bacterial diseases in aquaculture animals.

A crystalline carbon nitride-based separator for high-performance lithium metal batteries.

Lithium metal anodes with ultrahigh theoretical capacities are very attractive for assembling high-performance batteries. However, uncontrolled Li dendrite growth strongly retards their practical applications. Different from conventional separator modification strategies that are always focused on functional group tuning or mechanical barrier construction, herein, we propose a crystallinity engineering-related tactic by using the highly crystalline carbon nitride as the separator interlayer to suppress dendrite growth. Interestingly, the presence of Cl- intercalation and high-content pyrrolic-N from molten salt treatment along with highly crystalline structure enhanced the interactions of carbon nitride with Li+ and homogenized lithium flux for uniform deposition, as supported by both experimental and theoretical evidences. The Li-Li cell with the modified separator therefore delivered ultrahigh stability even after 3,000 h with dendrite-free cycled electrodes. Meanwhile, the assembled Li-LiFePO4 full-cell also presented high-capacity retention. This work opens up opportunities for design of functional separators through crystallinity engineering and broadens the use of C3N4 for advanced batteries.

SOX1 acts as a tumor hypnotist rendering nasopharyngeal carcinoma cells refractory to chemotherapy.

SOX1, a well-known tumor suppressor, delays malignant progression in most cancer types. However, high expression of SOX1 in late-stage head and neck squamous cell carcinoma leads to poor prognosis. In this study, we show that SOX1 induces nasopharyngeal carcinoma (NPC) cells to enter a quiescent state. Using a model that mimics therapeutic resistance and tumor recurrence, a subpopulation of SOX1-induced NPC cells is refractory to paclitaxel, a cell cycle-specific chemotherapy drug. These cells maintain a quiescent state with decreased translational activity and down-regulated cell growth potential. However, once SOX1 expression is decreased, the NPC cells recover and enter a proliferative state. The chemotherapy resistance induced by SOX1 can not pass to next generation, as the cells that undergo re-proliferation become sensitive to paclitaxel again. Moreover, SOX1 directly binds to the promoter region of the MYC gene, leading to transcriptional suppression. When switching to a paclitaxel-free culture environment, the cells with decreased levels of SOX1 re-express MYC, resulting in increased abundance of proliferative cancer cells. Our study presents an evolutionary trade-off between tumor growth and chemoresistance orchestrated by SOX1-MYC in NPC. Basing on the dynamic role of SOX1 in different stages of cancer development, SOX1 would be regarded as a "tumor hypnotist".

An Amorphous Anode for Proton Battery.

Developing advanced electrode materials is crucial for improving the electrochemical performances of proton batteries. Currently, the anodes are primarily crystalline materials which suffer from inferior cyclic stability and high electrode potential. Herein, we propose amorphous electrode materials for proton batteries by using a general ion-exchange protocol to introduce multivalent metal cations for activating the host material. Taking Al3+ as an example, theoretical and experimental analysis demonstrates electrostatic interaction between metal cations and lattice oxygen, which is the primary barrier for direct introduction of the multivalent cations, is effectively weakened through ion exchange between Al3+ and pre-intercalated K+. The as-prepared Al-MoOx anode therefore delivered a remarkable capacity and outstanding cycling stability that outperforms most of the state-of-the-art counterparts. The assembled full cell also achieved a high voltage of 1.37 V. This work opens up new opportunities for developing high-performance electrodes of proton batteries by introducing amorphous materials.

An ultralong-life SnS-based anode through phosphate-induced structural regulation for high-performance sodium ion batteries.

As a star representative of transition metal sulfides, SnS is viewed as a promising anode-material candidate for sodium ion batteries due to its high theoretical capacity and unique layered structure. However, the extremely poor electrical conductivity and severe volume expansion strongly hinder its practical application while achieving a high reversible capacity with long-cyclic stability still remains a grand challenge. Herein, different from the conventional enhancement method of elemental doping, we report a rational strategy to introduce PO43- into the SnS layers using phytic acid as the special phosphorus source. Intriguingly, the presence of PO43- in the form of Sn-O-P covalent bonds can act as a conductive pillar to buffer the volume expansion of SnS while expanding its interlay spacing to allow more Na+ storage, supported by both experimental and theoretical evidences. Profiting from this effect combined with microstructural metrics by loading on high pyridine N-doped reduced graphene oxide, the as-prepared material presented an unprecedented ultra-long cyclic stability even after 10,000 cycles along with high reversible capacity and excellent full-cell performances. The findings herein open up new opportunities for elevating electrochemical performances of metal sulfides and provide inspirations for the fabrication of advanced electrode materials for broad energy use.

[Effect of Xingnao Kaiqiao acupuncture on safety of rt-PA intravenous thrombolysis in patients with cerebral infarction: a randomized controlled trial].

OBJECTIVE: To assess the effect of Xingnao Kaiqiao (regaining consciousness and opening orifices) acupuncture on the efficacy and safety of intravenous thrombolysis with recombinant tissue plasminogen activator (rt-PA) in patients with cerebral infarction. METHODS: A total number of 142 patients of cerebral infarction undergoing rt-PA intravenous thrombolysis were randomized into an acupuncture-medication group (71 cases) and a western medication group (71 cases, 1 case dropped off). In the western medication group, rt-PA intravenous thrombolysis was given. In the acupuncture-medication group, besides the intervention as the control group, Xingnao Kaiqiao acupuncture was provided at Shuigou (GV 26), Neiguan (PC 6), Sanyinjiao (SP 6), Jiquan (HT 1), etc. once daily. One treatment session contained 6 treatments and 1 session was required. Before and after treatment, the score of the National Institute of Health stroke scale (NIHSS), the levels of the relevant indexes of symptomatic intracerebral hemorrhage (sICH) (platelet [PLT], D-dimer and fibrinogen), the incidences of sICH and adverse effect were compared between groups. The efficacy was assessed in two groups. RESULTS: After treatment, NIHSS scores and the levels of D-dimer were reduced compared with those before treatment in both groups (P<0.05), and those in the acupuncture-medication group were lower than the western medication group (P<0.05). The level of fibrinogen in the acupuncture-medication group was increased in comparison with that before treatment (P<0.05), and also higher than the western medication group (P<0.05). The incidence of sICH was 0% (0/71) in the acupuncture-medication group, lower than 8.6% (6/70) in the western medication group (P<0.05). The effective rate was 97.2% (69/71) in the acupuncture-medication group, higher than 87.1% (61/70) in the western medication group (P<0.05). The incidence of adverse effect was 2.8% (2/71) in the acupuncture-medication group, lower than 12.9% (9/70) in the western medication group (P<0.05). CONCLUSION: Xingnao Kaiqiao acupuncture may improve the efficacy of rt-PA intravenous thrombolysis in the patients with cerebral infraction and decrease the incidences of sICH and adverse effect. The mechanism may be related to the regulation of fibrinogen and D-dimer levels.

[FU Li-xin's experience in treatment of vertigo with "regulating the middle jiao, opening gate and relaxing tendon" method of acupuncture].

The paper introduces professor FU Li-xin's theoretic ideas and experience in treatment of vertigo. Professor FU believes that this disease is closely related to the blockage of qi movement in the middle jiao, opening-closing disarrangement in the pivot, "gate" obstruction, malnutrition of brain orifice and decreased blood flow in the nape. Based on the holistic idea of qi movement in traditional Chinese medicine and the circulatory theory of western medicine, the characteristics of the specific acupuncture therapy for "regulating the middle jiao, opening gate and relaxing tendon" are summarized. Using the layered needling technique at Zhongwan (CV 12) and "gate points" in the neck region, the tendon-bone needling technique with modified "dark tortoise seeking hole" at local tendon blockage points, vertigo is cured through regulating qi in the middle jiao, opening gate and nourishing marrow, relaxing tendon and harmonizing the mind.

Effective modification of photocatalytic and piezocatalytic performances for poly(heptazine imide) by carbon dots decoration.

As the high-crystalline phase of carbon nitride, poly(heptazine imide) (PHI) has attracted much attention in recent years, considering the more effective light absorption, better charge carrier behavior, and higher surface area of PHI compared with its counterpart with a melon structure that is commonly synthesized through thermal polymerization. Nevertheless, exploring effective strategies to further improve the performance of PHI is still highly desirable. In this work, it is revealed that the photocatalytic as well as piezocatalytic performances of PHI are greatly promoted by coupling with carbon dots (CDots) through a facile ultrasonication process. Detailed structure characterizations indicate that a very low content of CDots (0.05%) decoration can double the light absorbance and achieve the efficient separation and transfer of photogenerated charge carriers. The optimal photocatalytic hydrogen evolution rate of PHI/CDots is about 2.49 and 2.81 times that of PHI, under UV-Visible and visible light irradiation, respectively. Moreover, the piezocatalytic H2O2 generation and KMnO4 degradation activities of PHI/CDots are around 2 times that of PHI. The results obtained in this work provide references for the modification of PHI and may inspire new strategies for the design of highly efficient carbonaceous photocatalysts.

Constructing porous carbon nitride nanosheets for efficient visible-light-responsive photocatalytic hydrogen evolution.

The photocatalytic performance of polymeric carbon nitride (CN) is mainly restricted by the poor mass charge separation efficiency and poor light absorption due to its polymeric nature. The conventional strategies to address these problems involved constructing a nanosheets structure would result in a blue shifted light absorption and increased exciton binding energy. Here, with combination of ammonia etching and selectively hydrogen-bond breaking, holey carbon nitride nanosheets (hCNNS) were constructed, thus widening the light absorption range, and spontaneously shortening the migration distance of electrons and holes in the lateral and vertical directions, respectively. Further analysis also found out the reserved atomic structure order endowed hCNNS with the relatively high redox potential. When irradiated with visible light (λ > 420 nm) and loaded with 3 wt% Pt as the cocatalyst, the hydrogen evolution rate of hCNNS was about 40 times higher than the bulk CN, and the apparent quantum yield (AQY) of hCNNS is 1.47% at 435 ± 15 nm. We expect this research can provide a new sight for achieving highly efficient solar utilization of CN-based photocatalysts.

Relationship of ERCC5 genetic polymorphisms with metastasis and recurrence of gastric cancer.

OBJECTIVE: This study aims to explore the role of ERCC5 genetic polymorphisms in gastric cancer and their relationship with metastasis and recurrence of gastric cancer. METHODS: A total of 200 patients with gastric cancer and 133 healthy subjects were enrolled. MassARRAY iPLEX® technology was used to genotype ERCC5 rs2016073, rs751402, rs2094258, rs2296147, and rs2296148 between the control group and the gastric cancer group. The relationship of ERCC5 genetic polymorphisms with metastasis and recurrence of gastric cancer was explored. The differences in sociodemographic characteristics between patients with gastric cancer and control subjects were compared using the chi-square test. The genetic loci between the control group and the gastric cancer group were analyzed by the chi-square test. RESULTS: There was no significant difference in the metastasis of gastric cancer between males and females (p=0.628), but there was a significant difference in the metastasis of gastric cancer (p=0.005). Patients aged ≤60 years and >60 years showed no significant difference in the metastasis of gastric cancer (p=0.420), but there was a significant difference in the recurrence of gastric cancer (p<0.001). The loci rs2016073, rs751402, and rs2094258 in the gastric cancer group showed no significant differences compared with the control group (p=0.194), and the loci rs2296147 and rs2296148 showed significant differences. CONCLUSIONS: The results suggested that ERCC5 polymorphisms (e.g., rs201607, rs751402, rs2094258, rs2296147, and rs2296148) may be associated with metastasis and recurrence of gastric cancer.

Modulation of oxidative phosphorylation augments antineoplastic activity of mitotic aurora kinase inhibition.

Uncontrolled mitosis is one of the most important features of cancer, and mitotic kinases are thought to be ideal targets for anticancer therapeutics. However, despite numerous clinical attempts spanning decades, clinical trials for mitotic kinase-targeting agents have generally stalled in the late stages due to limited therapeutic effectiveness. Alisertib (MLN8237) is a promising oral mitotic aurora kinase A (AURKA, Aurora-A) selective inhibitor, which is currently under several clinical evaluations but has failed in its first Phase III trial due to inadequate efficacy. In this study, we performed genome-wide CRISPR/Cas9-based screening to identify vulnerable biological processes associated with alisertib in breast cancer MDA-MB-231 cells. The result indicated that alisertib treated cancer cells are more sensitive to the genetic perturbation of oxidative phosphorylation (OXPHOS). Mechanistic investigation indicated that alisertib treatment, as well as other mitotic kinase inhibitors, rapidly reduces the intracellular ATP level to generate a status that is highly addictive to OXPHOS. Furthermore, the combinational inhibition of mitotic kinase and OXPHOS by alisertib, and metformin respectively, generates severe energy exhaustion in mitotic cells that consequently triggers cell death. The combination regimen also enhanced tumor regression significantly in vivo. This suggests that targeting OXPHOS by metformin is a potential strategy for promoting the therapeutic effects of mitotic kinase inhibitors through the joint targeting of mitosis and cellular energy homeostasis.

[Characteristics and Source of VOCs During O3 Pollution Between August to September, Langfang Development Zones].

A total of 99 volatile organic compound(VOC) species were detected the Langfang development zones based on continuous monitoring using a ZF-PKU-1007 between August 25 and September 30, 2018. The concentrations, reactivity, and sources of VOCs were studied under different O3 concentrations using compositional analysis. The results showed that the average VOCs concentration during the research period was(75.17±38.67)×10-9, and was(112.33±30.96)×10-9, (66.25±34.84)×10-9 on pollution days and cleaning days, respectively(VOCs concentrations were 69.6% higher on pollution days). The contribution of VOCs species to the ozone formation potential(OFP) were ranked in the order aldehydes > aromatics > alkenes > alkanes. In the case of L·OH, the main contributions were from aromatics(30.0%) and alkenes(25.8%) on pollution days, while the contribution from aromatic alkenes(29.8%) was a slightly higher than aromatics(28.0%) on cleaning days. By applying the positive matrix factorization(PMF) model, five major VOCs sources were extracted, namely vehicle emissions(34.4%), solvent usage and evaporation(31.7%), the petrochemical industry(15.7%), combustion(11.1%), and plant emissions(7.9%). The contributions of solvent usage and evaporation and plant emission sources on pollution days were 13.1% and 1.2% higher than on cleaning days, respectively, which was likely due to relatively higher temperatures on these days. Therefore, vehicle emissions and solvent usage and evaporation should be priorities in VOCs control strategies for the Langfang development zones between August to September.

[Effects of tillage alternation pattern with subsoiling on soil physical and chemical properties and spring maize yield in the Loess Plateau, China]. / 深松轮耕模式对黄土旱塬春玉米土壤理化性质和作物产量的影响.

Straw mulching and subsoiling can protect soil and improve soil structure. However, long-term continuous subsoiling cannot continuously gain yield increasing and soil improvement. To realize continuous soil improvement and yield enhancement, a long-term experiment on subsoiling alternation patterns was carried out with spring maize continuous cropping in the Loess Plateau in 2007-2016. The subsoiling alternation patterns were no-tillage/conventional tillage/subsoiling (NT/CT/ST) and subsoiling/conventional tillage (ST/CT), with continuous subsoiling (ST) as control. We analyzed the effects of the different patterns on soil physical and chemical properties and maize yield. The results showed that, compared with the ST, the mechanical-stable aggregates (DR0.25) and water-stable aggregates (WR0.25) in NT/CT/ST were significantly increased by 9.2% and 21.9%, with the mean weight diameter (MWD) and geometrical mean diameter (GMD) being significantly increased. The WR0.25 in ST/CT was significantly increased by 11.9%. In 0-20 cm soil layer, soil bulk density in NT/CT/ST and ST/CT decreased by 7.0% and 11.5%, and soil porosity increased by 8.4% and 13.9%, respectively. In 20-40 cm soil layer, soil bulk density in ST/CT increased by 6.9%, and soil porosity decreased by 5.7%. In the NT/CT/ST, soil total nitrogen and organic matter contents significantly increased, but soil total phosphorus and total potassium contents reduced. The multi-year average grain yield of spring maize in NT/CT/ST was 10.2% higher than ST and 4.8% higher than ST/CT. The DR0.25, WR0.25, soil total nitrogen content and soil organic carbon content were all positively correlated with maize yield, indicating such changes faci-litated corn grain yield. Considering the effects on soil fertility and corn yield, the NT/CT/ST model was conducive to soil fertility, soil structural stability and higher maize yield.

No tillage increases soil organic carbon storage and decreases carbon dioxide emission in the crop residue-returned farming system.

Soil organic carbon (SOC) storage and carbon dioxide (CO2) emission under different tillage methods in a crop residue-returned farming system may not be consistent with result from studies of the usual tillage researches because crop residues are important carbon sources with significant effects on soil carbon input and output. Herein, we address a knowledge gap over the "hot spot" research on tillage practices on SOC storage and CO2 emission in crop residue-returned farming systems. In this study, a long-term (2007-2019) field experiment was conducted, and the crop residues were returned to the soil after harvest; then, three tillage methods were conducted: no tillage (NT), subsoiling tillage (ST), and a moldboard plow tillage (CT). Our results showed that in the crop residue-returned farming system, NT and ST still showed advantages of lower CO2 flux compared with CT, as well as a reduced average CO2 flux of 14.5% and 8.5%, respectively, over a two-year average. The results of our long-term study suggest that the NT had advantages of SOC accumulation. In addition, as of June 2018, NT increased SOC stocks with 5.85 Mg hm-2 at a 0-60-cm soil depth compared with CT, whereas no significant difference was found between ST and CT. Overall, adopting NT in a crop residue-returned farming system improved SOC storage to 5.85 Mg hm-2 after 11 years as well as decreased CO2 flux by 14.5% in comparison with CT, which is meaningful in improving soil carbon pool and decreasing soil CO2 emission during agriculture production.

Ferroelectric Oxide Nanocomposites with Trimodal Pore Structure for High Photocatalytic Performance.

An effective method to improve the photocatalytic performances of powder catalysts is to use the internal electric field from ferroelectrics to separate photogenerated charge carriers. The design and engineering of a complex hetero-junction with a hierarchical pore structure is highly desirable for the efficient application of ferroelectric materials in photocatalysis. Here, we present a novel strategy using two templates to fabricate PbTiO3/TiO2/carbon (PTC) nanocomposites with a tunable microstructure. A hard SiO2 template combined with an ice template followed by an appropriate pyrolysis procedure introduced trimodal (micro-, meso-, macro-) porosity. The as-prepared PTC nanocomposites with optimal mass ratio exhibited excellent photocatalytic and photoelectrochemical performances. PbTiO3/TiO2 annealed at 900 °C (PTC-900) showed a MB degradation rate of 0.21 and 0.021 min-1 under UV and visible light irradiation, which are, respectively, 7.2 and 3 times those of pure PbTiO3. The photocurrent density of the composite catalyst is 1.48 mA cm-2 at the potential of 1.0 V versus saturated calomel electrode, and the rates of hydrogen generation of PTC-900 are as high as 2360 and 9.6 µmol h-1 g-1 under UV and visible light irradiation, respectively. More importantly, the simultaneous application of ultrasound-induced mechanical waves further improved the photocatalytic reactivity. This work serves to improve understanding on the design of ferroelectric/piezoelectric photocatalysts with a hierarchical pore structure and also proposes a widely applicable strategy for the fabrication of high-performance micro-nano/nano-nano structures.