Highly efficient hydrogen evolution catalysis based on MoS₂/CdS/TiO₂ porous composites

Du, Jimin,Wang, Huiming,Yang, Mengke,Zhang, Fangfang,Wu, Haoran,Cheng, Xuechun,Yuan, Sijie,Zhang, Bing,Li, Kaidi,Wang, Yina,Lee, Hyoyoung Elsevier 2018 International journal of hydrogen energy Vol.43 No.19

<P><B>Abstract</B></P> <P>Efficient production of hydrogen through visible-light-driven water splitting mechanism using semiconductor-based composites has been identified as a promising strategy for converting light into clean H<SUB>2</SUB> fuel. However, researchers are facing lots of challenges such as light absorption and electron-hole pair recombination and so on. Here, new sheet-shaped MoS<SUB>2</SUB> and pyramid-shaped CdS <I>in-situ</I> co-grown on porous TiO<SUB>2</SUB> photocatalysts (MoS<SUB>2</SUB> CdSTiO<SUB>2</SUB>) are successfully obtained <I>via</I> mild sulfuration of MoO<SUB>3</SUB> and CdO coexisted inside porous TiO<SUB>2</SUB> monolith by a hydrothermal route. The scanning electron microscopy and transmission electron microscopy results exhibit that the MoS<SUB>2</SUB> CdSTiO<SUB>2</SUB> composites have average pore size about 500 nm. The 3%MoS<SUB>2</SUB> 10%CdSTiO<SUB>2</SUB> demonstrated excellent photocatalytic activity and high stability for a hydrogen production with a high H<SUB>2</SUB>-generation rate of 4146 μmol h<SUP>−1</SUP> g<SUP>−1</SUP> under visible light irradiation even without noble-metal co-catalysts. The super photocatalytic performance of the visible-light-driven hydrogen evolution is predominantly attributed to the synergistic effect. The conduction band of MoS<SUB>2</SUB> facilitates in transporting excited electrons from visible-light on CdS to the porous TiO<SUB>2</SUB> for catalytic hydrogen production, and holes to MoS<SUB>2</SUB> for inhibiting the photocorrosion of CdS, respectively, leading to enhancing the efficient separation of electrons and holes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MoS<SUB>2</SUB>-CT photocatalysts have been successfully synthesized by two-step method. </LI> <LI> The porous structure can enhance photogenerated electron-hole pairs separation. </LI> <LI> The 3% MoS<SUB>2</SUB>-CT shows an excellent H<SUB>2</SUB> evolution rate of 4146 μmol h<SUP>−1</SUP> g<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Porous WO₃ monolith-based photoanodes for high-efficient photoelectrochemical water splitting

Wang, Yina,Zhang, Fangfang,Zhao, Guoyan,Zhao, Yingao,Ren, Yangyang,Zhang, Huijun,Zhang, Linyu,Du, Jimin,Han, Yumin,Kang, Dae Joon Elsevier 2019 CERAMICS INTERNATIONAL Vol.45 No.6

<P><B>Abstract</B></P> <P>We report a successful fabrication of low-cost, high-efficient, structurally-rigid, porous WO<SUB>3</SUB> photoelectrochemical (PEC) catalysts using polystyrene as the template by a sol-gel method and a high-temperature annealing treatment. The scanning electron microscopy and Brunauer-Emmett-Teller surface analysis results indicate that such WO<SUB>3</SUB> monoliths possess a porous structure and a large specific surface area, which can supply lots of photogenerated charge transfer pathways as well as more surface PEC active sites. Compared with a commercially available WO<SUB>3</SUB>, our highly porous WO<SUB>3</SUB> PEC catalysts show an excellent PEC water splitting activity. Particularly, the porous WO<SUB>3</SUB> photoanodes calcinated in the presence of oxygen atmosphere at 450 °C for 7 h show the best PEC performance exhibiting the photocurrent density of 0.97 mA/cm<SUP>2</SUP> at 1.23 V versus reversible the hydrogen electrode and the incident photon-to-current conversion efficiency up to 48.9% at 420 nm in 0.5 M Na<SUB>2</SUB>SO<SUB>4</SUB> electrolyte under AM 1.5 G irradiation. Such excellent PEC performance is due to the high porosity of the WO<SUB>3</SUB>, promoting the fast transfer and the separation rate of photogenerated carriers during the PEC water splitting process.</P>

Synthesis and Enhanced Photocatalytic Activity of Black Porous Zr-doped TiO2 Monoliths

Jimin Du,Huiming Wang,Huijuan Chen,Menghe Yang,Xiaoling Lu,Hui Guo,Zhanmin Zhang,Tianwei Shang,Shujue Xu,Wenqi Li,Pianpian Wang,Imran Shakir 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.6

Black Porous Zr-doped TiO2 monoliths were successfully synthesized by a combined route including sol–gel method with polystyrene spheres as template followed by calcination at high temperature in the presence of oxygen. As-synthesized samples were then treated in hydrogen atmosphere at 500℃ for 6 h to obtain black Porous Zr-doped TiO2 monoliths. This as-synthesized black porous Zr-doped TiO2 composite showed relatively narrow bandgap compared to the pure anatase phase of TiO2, which may have its origin from the contributions from the Zr impurity and oxygen vacancies. The photocatalytic activity of the black porous Zr-doped TiO2 monolith was examined by carrying out the dye degradation on Rhodamine B under visible irradiation. Our experimental results indicate that black porous 0.9% Zr-doped TiO2 sample exhibits high photocatalytic activity with the photodecomposition of 95.25% under visible irradiation for 120 min.

Enhanced charge separation of CuS and CdS quantum-dot-cosensitized porous TiO₂-based photoanodes for photoelectrochemical water splitting

Du, Jimin,Yang, Mengke,Zhang, Fangfang,Cheng, Xuechun,Wu, Haoran,Qin, Huichuang,Jian, Qingsong,Lin, Xialing,Li, Kaidi,Kang, Dae Joon Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.3

<P><B>Abstract</B></P> <P>Photoelectrochemical (PEC) water splitting using high-performance catalysts shows considerable promise in generating environment-friendly hydrogen energy. Its practical applications, however, suffer from several shortcomings, such as low photocurrent density, large onset-voltage value, and poor durability. In this study, CuS and CdS quantum-dot-cosensitized porous TiO<SUB>2</SUB>-based PEC catalysts (CuS-CT) have been successfully synthesized via in situ sulfuration of CuO and CdO coexisting inside a porous TiO<SUB>2</SUB> monolith by a hydrothermal method. Compared to porous TiO<SUB>2</SUB>, CuS-sensitized porous TiO<SUB>2</SUB> (CuS-TiO<SUB>2</SUB>), and CdS-sensitized porous TiO<SUB>2</SUB> (CdS-TiO<SUB>2</SUB>) in terms of PEC performance, the CuS-CT photoanode exhibited a significantly high anodic photocurrent for water splitting under simulated sunlight radiation. The photocurrent produced by the optimized sample of 7% CuS-5% CdS-TiO<SUB>2</SUB> (7% CuS-CT) was nearly 2.7 times higher than that of pure porous TiO<SUB>2</SUB> at 1.0V versus a reversible hydrogen electrode (RHE). Porous TiO<SUB>2</SUB> possesses large surface areas that can drive fast electrolyte transport and afford more surface reaction active sites. On the other hand, CuS and CdS quantum dots not only broaden the visible light absorption range, but also improve photoinduced electron-hole separation efficiency. The co-sensitized multi-nanostructures photoanodes lead to a remarkable and promising application in PEC water splitting reactions.</P>

Effect of the worn status of wheel/rail profiles on wheel wear over curved tracks

Jie Kou,Jimin Zhang,Hechao Zhou,Chengping Wang,Lixia Sun 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3

The worn status of wheel/rail profiles could change the wheel-rail contact and influence the wear rates of the wheel and rail. Worn wheel profiles of a Chinese intercity train and the worn rail profile of curved tracks were taken into account in this work. According to the dynamics model of the vehicle, teh wheel-rail three-dimensional steady-state rolling contact model, and the Archard wear model, a new fast calculation method of wheel wear rate was proposed. Simulation results show that obviously severe wear would distribute in the flange when the wheel and rail were worn. The side wear of rail gauge corner will seriously aggravate the wear of new wheel flange. The wear of the wheel is serious for teh worn wheel in the initial phase of service. Therefore, the re-profiling of wheels and rails should be scheduled cooperatively, and the wear of flange in the initial phase of service should addressed.

Analysis of the running quality and road friendliness of the virtual track train in multiple running stages between stations

Chengping Wang,Jimin Zhang,Hechao Zhou,Haiying Lu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

A virtual track train runs at fixed stations on designated lines. The short distance between stations requires frequent traction, uniform and braking, which will have a serious impact on vehicle performance and road life. A three-dimensional dynamics model of the virtual track train comprising three vehicles was established based on the theory of vehicle dynamics, tire dynamics, and nonlinear dynamics. The dynamics model comprised vehicle model and tireroad model, considering the dynamic coupling between vehicles and tire-road dynamic interaction. The field dynamic acceleration test of the actual virtual track train was used to validate the developed dynamics model. The running quality and road friendliness of the virtual track train in multiple running stages between stations were evaluated by theoretical analysis and numerical calculation. The results indicated that the running quality in the traction stage and braking stage is smaller than that in the uniform stage. The road friendliness in the uniform stage is better than that in the traction and braking stage. The increase in running speed and the decrease in road grade both reduce the running quality and road friendliness. The increase in acceleration or deceleration makes the road friendliness worse, and it has less impact on the running quality. The research results provide recommendations for the running mode of the virtual track train to improve the running quality. At the same time, they can provide guidance for asphalt pavement laying to slow down the road damage.

A stable and highly efficient visible-light-driven hydrogen evolution porous CdS/WO₃/TiO₂ photocatalysts

Qian, Yongteng,Yang, Mengke,Zhang, Fangfang,Du, Jimin,Li, Kaidi,Lin, Xialing,Zhu, Xinrui,Lu, Yayun,Wang, Weimin,Kang, Dae Joon Elsevier 2018 Materials characterization Vol.142 No.-

<P><B>Abstract</B></P> <P>It is well known that both catalytic efficiency and stability are the two important parameters of photocatalysts for visible-light-driven hydrogen production reactions. However, light-driven hydrogen evolution based applications still suffer from sluggish reaction kinetics due to the lack of high-performance photocatalysts. In this paper, we successfully synthesized a ternary porous CdS/WO<SUB>3</SUB>/TiO<SUB>2</SUB> photocatalyst with high efficiency and stability via two-stage approach. The as-prepared samples are characterized by XRD, FESEM, EDS, TEM, XPS, and UV–Vis, respectively, which illustrated that the CdS and WO<SUB>3</SUB> moieties are in-situ formed inside the porous TiO<SUB>2</SUB>. Particularly, the photocatalytic hydrogen (H<SUB>2</SUB>) evolution rate of such ternary 8% CdS/WO<SUB>3</SUB>/TiO<SUB>2</SUB> (molar ration of CdS:WO<SUB>3</SUB>:TiO<SUB>2</SUB> = 8:8:100) photocatalyst ranges up to 2106 μmol h<SUP>−1</SUP> g<SUP>−1</SUP> under visible-light irradiation, which is higher than that of pure TiO<SUB>2</SUB> and other binary (CdS/TiO<SUB>2</SUB> and WO<SUB>3</SUB>/TiO<SUB>2</SUB>) porous photocatalysts. The superior H<SUB>2</SUB> evolution efficiency can be attributed to the coexistence of CdS and WO<SUB>3</SUB> in porous TiO<SUB>2</SUB> which can promote the interfacial charge transfer and separation as well as extend the light absorption up to the visible range.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly efficient and stable photocatalytic activity of CdS/WO<SUB>3</SUB>/TiO<SUB>2</SUB> photocatalysts were synthesized by a two-step method. </LI> <LI> CdS and WO<SUB>3</SUB> inlaid on porous TiO<SUB>2</SUB> can extend the light absorption and enhance photogenerated electron-hole pairs separation. </LI> <LI> The porous structure can provide more reaction active sites and improve photoproduced-electrons and holes transport speed. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Highly Efficient Photocatalysts Based on Lamellar-Shaped Bi2S3 Grown on TiO2 Monolith

Kaidi Li,Fangfang Zhang,Huiming Wang,Yalan Zhou,Lixin Zhao,Jimin Du,Yating Gao,Weimin Wang,강대준 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.09

Here, the lamellar-shaped Bi2S3 grown on a porous TiO2 monolith was obtained by a two-step method including a sol–gel route and hydrothermal treatment. The photocatalytic activity of the as-synthesized Bi2S3/TiO2 composites was evaluated for photodegradation of methylene blue (MB) dye in aqueous solution under the visible-light irradiation. Based on our experimental results, 5% (molar ratio of Bi2S3 to TiO2) Bi2S3/TiO2 photocatalysts exhibited a maximum photodegradation rate of MB up to 96.9% under visible-light irradiation for 120 min. Our findings indicated that the lamellar-shaped Bi2S3 can extend the light absorption up to visible areas, and porous TiO2 can provide enhanced specific surface area and more mass transfer pathway to enhance the photodegradation efficiency. Furthermore, porous TiO2 can accept the electrons from the Bi2S3 conduction band due to the relatively positive electrode potential to impede the photoproduced electron and hole combination to result in advanced photocatalytic performance.

Particulate matter increases beta-amyloid and activated glial cells in hippocampal tissues of transgenic Alzheimer's mouse: Involvement of PARP-1

Jang, Sooah,Kim, Eun Woo,Zhang, Yinhua,Lee, Jimin,Cho, So Yeon,Ha, Junghee,Kim, Hyunjeong,Kim, Eosu Elsevier 2018 Biochemical and biophysical research communication Vol.500 No.2

<P><B>Abstract</B></P> <P>Exposure to air pollutants, such as particulate matter (PM), has been implicated in neurodegenerative disorders including Alzheimer's disease (AD). However, direct effects of PM on production of β-amyloid (Aβ), a key pathogenic molecule in AD, and its underlying mechanism are still elusive. Given PM's potential to induce oxidative stress in other tissues, we hypothesized that poly(ADP-ribose) polymerase (PARP-1) might be involved in PM-induced neurotoxicity. To address this, we used an <I>ex vivo</I> model of AD, the organotypic hippocampal slice tissue culture from old (12-14 months-of-age) triple transgenic 3xTg-AD mice. First, we observed that fine PM (aerodynamic diameter < 4 μm) can dose-dependently activate PARP-1 and decrease NAD<SUP>+</SUP> levels in Neuro2A cells. PARP-1 activation did occur under concentrations of PM which did not affect cell viability. Next, we observed that direct treatment of PM increased Aβ levels and activated glial cells in the <I>ex vivo</I> hippocampal tissues of 3xTg-AD mice. PM-induced glial activation was most prominent in CA1 region of the hippocampal tissue. Notably, we found that pharmacological inhibition of PARP-1 reversed both PM-induced Aβ increase and glial activation, arguing the possible involvement of PARP-1 in PM-induced AD pathogenesis. Our findings suggest that PARP-1 might be a potential molecular target, responsible for mediating negative effects of PM on the brain. Modulating PARP-1 activity could be a promising approach to prevent or alleviate PM-related environmental neurotoxicity which could initiate AD pathogenesis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Particulate matter (PM) activates PARP-1 in neuronal cells. </LI> <LI> PM increases beta-amyloid in <I>ex vivo</I> hippocampus of 3xTg-AD mouse. </LI> <LI> PM activates glial cells in <I>ex vivo</I> hippocampus of 3xTg-AD mouse. </LI> <LI> Pharmacological inhibition of PARP-1 reverses PM-induced AD pathologies. </LI> <LI> PARP-1 inhibition would be a promising approach counteracting PM's neurotoxicity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Distribution of Organic Carbon and Nitrogen Associated with Aggregates in Semiarid Conifer Forest of the Loess Plateau, China

Hailong Gao,Liping Qiu,Xingchang Zhang,Jimin Cheng 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6