One-pot synthesis of sulfur and nitrogen codoped titanium dioxide nanorod arrays for superior photoelectrochemical water oxidation

Andoshe, Dinsefa M.,Yim, Kanghoon,Sohn, Woonbae,Kim, Changyeon,Kim, Taemin Ludvic,Kwon, Ki Chang,Hong, Kootak,Choi, Seokhoon,Moon, Cheon Woo,Hong, Seung-Pyo,Han, Seungwu,Jang, Ho Won Elsevier 2018 Applied Catalysis B Vol.234 No.-

<P><B>Abstract</B></P> <P>Despite its abundant, nontoxicity and photochemical stability, titanium dioxide shows low solar water oxidation performance due to low photogenerated carrier transport and wide optical band gap, which results in substantially low photogenerated carrier density that impair the solar to hydrogen conversion efficiency. Herein, highly enhanced water oxidation performance of high-aspect-ratio TiO<SUB>2</SUB> nanorods doped with dual heteroatoms, sulfur and nitrogen, for photoelectrochemical solar water oxidation is demonstrated. The codoped TiO<SUB>2</SUB> NRs have shown enhanced optical absorption coefficient due to the induced impurities energy states near to the top of the valance band and result in a red shift in the optical absorption edges. Consequently, a 2.82 mAcm<SUP>−2</SUP> photocurrent density at 1.23 V vs. RHE is obtained from the sulfur and nitrogen codoped TiO<SUB>2</SUB> nanorods, and pristine TiO<SUB>2</SUB> nanorods photoanode shows 0.7 mAcm<SUP>−2</SUP>. The applied bias photon-to-current conversion efficiency and external quantum efficiency of the codoped TiO<SUB>2</SUB> nanorods are 1.49% and 97.0% at λ = 360 nm and 0.69% and 19.1% at λ = 370 nm for pristine TiO<SUB>2</SUB> nanorods, respectively. Our study offers experimental and theoretical evidence for codoping of sulfur and nitrogen improve the optical and electrical properties of TiO<SUB>2</SUB> for efficient photoelectrochemical solar water oxidation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Our S, N codoped TiO<SUB>2</SUB> NRs photoanodes synthesized by one-pot synthesis method exhibit the excellent photoelectrochemical performance. </LI> <LI> The influence of dual heteroatom doping with sulfur and nitrogen on optical and electrical properties was elucidated by experiments and theoretical calculation. </LI> <LI> The dual heteroatom doping with sulfur and nitrogen decreases the dopant formation energy and improves the optical absorption coefficient of TiO<SUB>2</SUB> NRs. </LI> <LI> In UV wavelength region, our samples show the incident photon up to a current efficiency of 97%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A photoanode prepared using titanium dioxide nanorods Arrays codoped with sulfur and nitrogen shows the highest water oxidation performance relative to cocatalyst-free TiO<SUB>2</SUB> photoanodes reported to date for photoelectrochemical water splitting. The outperformance of the TiO<SUB>2</SUB> (S, N) NRs mainly resulted from the induced energy states between the conduction and valence band of TiO<SUB>2</SUB>, which enhances the optical absorption and charge transport of the TiO<SUB>2</SUB> NRs.</P> <P>[DISPLAY OMISSION]</P>

Investigation of electronic and optical properties in Al-Ga codoped ZnO thin films

Lee, W.,Shin, S.,Jung, D.R.,Kim, J.,Nahm, C.,Moon, T.,Park, B. Elsevier 2012 Current Applied Physics Vol.12 No.3

Electronic and optical properties of Al-Ga codoped ZnO thin films were investigated by post-annealing. The lowest resistivity of the Al-Ga codoped ZnO films was observed from the 450 <SUP>o</SUP>C-annealed sample. The Fermi-level shift of the Al-Ga codoped ZnO film was ∼0.6 eV from x-ray photoelectron spectroscopy, and the widening of optical-bandgap in the Al-Ga codoped ZnO film was ∼0.3 eV. The correlations of optical-bandgap with Fermi-level shift and conduction band filling were suggested by schematic band diagrams.

Investigation of electronic and optical properties in Al-Ga codoped ZnO thin films

이우진,신성진,정대룡,김종민,남창우,문태호,박병우 한국물리학회 2012 Current Applied Physics Vol.12 No.3

Electronic and optical properties of Al-Ga codoped ZnO thin films were investigated by post-annealing. The lowest resistivity of the AleGa codoped ZnO films was observed from the 450 ℃-annealed sample. The Fermi-level shift of the Al-Ga codoped ZnO film was w0.6 eV from x-ray photoelectron spectroscopy,and the widening of optical-bandgap in the Al-Ga codoped ZnO film wasw0.3 eV. The correlations of optical-bandgap with Fermi-level shift and conduction band filling were suggested by schematic band diagrams.

Efficient solar-light photocatalytic H2 evolution of Mn0.5Cd0.5S coupling with S,N-codoped carbon

Hao Peng,Congying Huang,Xiaogang Zheng,Jing Wen 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

The low-cost and highly-efficient photocatalysts for solar-light induced water splitting had drawn greatattention to develop the renewable hydrogen economy. To enhance the solar-light driven H2 evolution ofMn0.5Cd0.5S, Mn0.5Cd0.5S was modified by S,N-codoped carbon (3-MCS/SN-C) via the in-situ sulfurizationat high temperature. In contrast with Mn0.5Cd0.5S (11.13 mmol g1 h1) and S-doped g-C3N4(0.35 mmol g1 h1), the optimal 3-MCS/SN-C with a mass ratio of Mn0.5Cd0.5S to S,N-codoped carbonof 1:3 exhibited the best H2 evolution rate of 27.58 mmol g1 h1 and an apparent quantum yield of27.43% at 400 nm. The photo-corrosion induced to the decreased H2 evolution capacity of 3-MCS/SN-Cfrom 131.13 to 126.52 mmol g1 after five cycles of 5 h. S,N-codoped carbon could efficiently capture visiblelight and absorb the photons, leading to the efficient transformation and separation of photogeneratedcarriers at the junction interface between Mn0.5Cd0.5S and S,N-codoped carbon.

Effects of sodium dodecyl sulfate surfactant on up-conversion luminescence of Er3+/Yb3+ -codoped NaLa (MoO4)2 nanocolloidal phosphor prepared by pulsed laser ablation in water

Suk Hyun Kang, Kyung-Hwan Jung,Jeong Ho Ryu,Kang Min Kim,Won Rae Kim,HyukSu Han,Sungwook Mhin,Yong Son,Kwang Bo Shim,Jung-Il Lee 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.2

Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals were synthesized by pulsed laser ablations in de-ionized water andsodium dodecyl sulfate (NaC12H25SO4, SDS) aqueous solution for up-conversion (UC) luminescence bio-labeling applications. The influences of the SDS molecules on the crystallinities, crystal morphologies, crystallite sizes, and UC luminescence propertiesof the prepared Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals were investigated in detail. Under a 980-nm excitation,the Er3+/Yb3+-codoped nanocolloidal NaLa(MoO4)2 suspension exhibited a weak red emission near 670 nm and strong green UCemissions at 530 and 550 nm, corresponding to the intra 4f transitions of Er3+ (4F9/2, 2H11/2 , 4S3/2)→Er3+ (4I15/2). When the SDSsolution was used, a smaller average crystallite size, narrower size distribution, and enhanced UC luminescence were observed. These characteristics were attributed to the amphoteric SDS molecules attached to the positively charged Er3+/Yb3+-codopedNaLa(MoO4)2 colloidal nanocrystals, effectively occupying the oxygen defect on their surfaces. The Er3+/Yb3+-codopednanocrystalline NaLa(MoO4)2 suspension prepared in the SDS solution exhibited a remarkably strong green emission visibleto the naked eyes.

Effect of Gas Sensing Properties by Sn-Rh Codoped ZnO Nanosheets

Ziwei Chen,Zhidong Lin,Mengying Xu,Yuyuan Hong,Na Li,Ping Fu,Ze Chen 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.3

The hierarchically porous Sn-Rh codoped ZnO, Sn-doped ZnO and pureZnO nanosheets have been successfully synthesized through a simplehydrothermal reaction process without any surfactant or template at 180°C. The morphology and composition were carefully characterized by X-raydiffraction, energy dispersive X-ray spectrometer, field emission scanningelectronic microscopy and BET. The gas-sensing testing results indicatedthat the Sn-Rh codoped ZnO nanosheets, with the specific surface area was26.9 m2/g, exhibited enhanced gas-sensing performance compared withthat of pure ZnO and Sn-doped ZnO. The high sensitivity of the sensorbased on Sn-Rh codoped ZnO was 149.38 to 100 ppm ethanol and thedetection limit was less than 5 ppm (5.8). The response and recovery timeswere measured to be ~3 s and ~10 s when exposed to 100 ppm ethanol atthe test temperature of 300°C. The good sensing performance of the Sn-Rhcodoped ZnO sensor indicated that hierarchically porous Sn-Rh codopedZnO could be a promising candidate for highly sensitive gas sensors.

Degradation and mineralization of violet-3B dye using C-N-codoped TiO₂ photocatalyst

Reza Audina Putri,Safni Safni,Novesar Jamarun,Upita Septiani,Moon-Kyung Kim,Kyung-Duk Zoh 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.4

The present study investigated the photodegradation of synthetic organic dye; violet-3B, without and with the addition of C-N-codoped TiO₂ catalyst using a visible halogen-lamp as a light source. The catalyst was synthesized by using a peroxo sol-gel method with free-organic solvent. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of violet-3B were examined. The efficiency of the photodegradation process for violet-3B dye was higher at neutral to less acidic pH. The kinetics reaction rate of photodegradation of violet-3B dye with the addition of C-N-codoped TiO₂ followed pseudo-first order kinetics represented by the Langmuir-Hinshelwood model, and increasing the initial concentration of dyes decreased rate constants of photodegradation. Photodegradation of 5 mg L<SUP>-1</SUP> violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO₂ catalyst, and approximately 44% TOC was removed as a result of the mineralization.

Highly efficient quantum cutting in Yb/Pr-codoped NaY(WO4)2 crystal

Chengguo Ming,Feng Song,Liqun An,Xiaobin Ren 한국물리학회 2014 Current Applied Physics Vol.14 No.8

Cutting one ultraviolet photon into three near-infrared (NIR) photons can effectively improve the efficiency of silicon solar cells. We prepared Yb-doped, Pr-doped, and Yb/Pr-codoped NaY(WO4)2 (NYW) crystals. The Yb/Pr-codoped sample can divide the ultraviolet and blue photons into ~1000 nm NIR photons, which brings strong emission at the NIR wavelength range. On the basis of the luminescence spectra and lifetime analysis, the quantum efficiency of the material is higher.

Facile synthesis of ternary TiO₂ NP/Rh & Sb-codoped TiO₂ NR/titanate NT composites photocatalyst: Simultaneous removals of Cd²⁺ ions and Orange (II) dye under visible light irradiation (λ≥420nm)

Kim, Su-Gyeong,Dhandole, Love Kumar,Lim, Jeong-Muk,Chae, Weon-Sik,Chung, Hee-Suk,Oh, Byung-Taek,Jang, Jum Suk Elsevier 2018 Applied Catalysis B Vol.224 No.-

<P><B>Abstract</B></P> <P>In this study, rhodium and antimony doped nanorod (RS-TONR) was prepared by a molten salt solid state chemical reaction, and TiO<SUB>2</SUB> nanorod and titanate nanotube (RS-TONR/TiNT) composite photocatalyst was synthesized by a hydrothermal method for different reaction times. The structural and chemical analyses of nanomaterials were performed by FE-SEM, XRD, UV-DRS and surface BET characterizations. The XRD and HR-TEM data confirmed that the as-synthesized material had mixed phase of TiO<SUB>2</SUB> nanorod and Titanate nanotube (RS-TONR/TiNT). The photocatalytic activity of the composite photocatalyst was observed over the degradation of Orange (II) dye under visible light irradiation. Acid treatment and copper loading was conducted to enhance the surface property of RS-TONR/TiNT sample. The formation of TiO<SUB>2</SUB> nanoparticle with anatase phase was observed by TEM and XRD analysis. The TEM mapping data also confirmed that copper oxide nanoparticles were well dispersed on the surface of titanate nanotubes. These dispersed nanoparticles were observed by XPS and STEM characterizations. The higher removal efficiency of Cd<SUP>2+</SUP> ions was observed over the acid treated and untreated Cu3-TNP/TiNT/RS-TONR in the presence of Orange (II) dye. A higher photocatalytic activity of acid treated and Cu3-TNP/TiNT/RS-TONR was simultaneously obtained in the presence of cadmium ions during the degradation of Orange (II) dye.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Rh and Sb co-doped crystalline rutile TiO<SUB>2</SUB> nanorod (NR) was synthesized via molten salt flux method. </LI> <LI> The RS-TONR/TiNT was hydrothermally synthesized for different reaction times. </LI> <LI> Acid treatment was conducted to enhance the surface property of RS-TONR/TiNT sample. </LI> <LI> Finely dispersed Cu<SUB>x</SUB>O on TNP/RS-TONR/TiNT significantly improves the photocatalytic activity. </LI> <LI> Synergistic effect in photocatalytic performance was studied by Orange (II) dye degradation and Cd<SUP>2+</SUP> ion adsorption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

(Cr, Fe)-doped Y₂O₃-Al₂O₃계 붉은 안료의 합성과 특성

신경현,이병하 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.4

Perovskite codoped with chromium and iron have been studied. Samples with YAl0.96(Cr0.04-xFex)O₃(x=0.01, 0.02, 0.03, 0.04) were prepared by solid state reaction at 1450℃ for 6 h and were characterized by XRD, FT-IR, Raman spectroscopy, SEM and UV-vis spectrophotometer. The color of the synthesized pigments were from red to dark brown(in bulk). Up to 0.02 mole Fe₂O₃ for substituting Cr₂O₃ development of color in lime-glaze gives good red color but as increasing amount of Fe₂O₃ and decreasing Cr₂O₃ proportionally produce from brownish red to brown. Increasing Fe₂O₃ amount lead to weaken crystal field relatively due to have smaller ionic radius than Cr₂O₃ ionic one. The UV-vis peaks were shifted to lower wavelength.