http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Surface and bulk modification for advanced electrode design in photoelectrochemical water splitting
Haider, Zeeshan,Yim, Hee Won,Lee, Hae Won,Kim, Hyoung-il Elsevier 2020 International journal of hydrogen energy Vol.45 No.10
<P><B>Abstract</B></P> <P>Photoelectrochemical (PEC) water splitting provides a prominent strategy for harnessing solar energy in the production of sustainable hydrogen fuel from water. Over the past few decades, extensive efforts have been devoted to develop advanced electrodes for efficient PEC water splitting. This review presents the recent progress in the development of efficient photoanodes through two major approaches: surface modification, including co-catalyst-loading, passivation, and defect engineering; and bulk modification, including hybridization, dopant engineering, and structural control. By virtue of bulk and surface modification a considerable improvement in PEC activity has been obtained so far. Photocurrent response of various anodes observed in the range of 0.063 mA cm<SUP>−2</SUP> – 8.5 mA cm<SUP>−2</SUP> (as listed in Table 1) require further improvement to upgrade the overall performance efficiency of PEC cells.</P> <P>This review also provides a systematic overview of the fundamentals of PEC water splitting, as well as the key challenges and notable achievements made so far in terms of electrode design and material modification. Finally, future research perspectives that will further advance this field are discussed. The contribution of this paper is to provide fundamental information about bulk and surface modifications, which will aid in the design of advanced electrodes for high-performance PEC cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Recent progress on developing advanced photoanodes for PEC water-splitting. </LI> <LI> Bulk and surface modifications synergistically enhance PEC performance. </LI> <LI> Critical factors determining the efficiency of the PEC cell have been highlighted. </LI> <LI> Future challenges and perspectives for sustainable PEC water-splitting are discussed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Haider, Zeeshan,Zheng, Jin You,Kang, Young Soo The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.29
<P>Unique octagonal shaped BiOCl nanosheets (NS) dominantly exposed with high energy {001} crystal facets have been fabricated via a simple hydrothermal route without using organic surfactants. The dynamics of photogenerated charge carriers have been studied by time-resolved photoluminescence spectroscopy. The fitting parameters of the decay kinetics were used to calculate both the intensity weighted average lifetime (<tau >(int.)), as well as the amplitude weighted average lifetime (<tau >(amp.)) of the photogenerated charge carriers. The <tau >(int.) and <tau >(amp.) values for {001} BiOCl NS, i.e., 17.23 ns and 1.94 ns, respectively, were observed to be significantly higher than the corresponding values obtained for pristine BiOCl such as 2.52 ns and 1.07 ns, respectively. Significant quenching of the PL emission intensity of {001} BiOCl NS reflected the enhanced separation of the photogenerated charge carriers. Reduced thickness and in situ iodine doping was favorable to minimize the recombination tendency. The photocatalytic activity was monitored via the photodegradation of RhB under visible light illumination (lambda > 400 nm). {001} BiOCl NS exhibited superior performance when compared to pristine BiOCl in terms of the rapid degradation kinetics and higher photonic efficiency. The photocatalytic efficiency of {001} BiOCl NS was 2.8 times higher than pristine BiOCl. Iodine doping induced extended the optical absorption in the visible region and improved the separation of the photogenerated charge carriers, which played an important role to enhance the photocatalytic activity. The photodegradation mechanism was systematically studied using various radical quenchers and it was revealed that photogenerated holes (h(+)) and superoxide radicals (O-center dot(2-)) actively participated whereas hydroxyl (OH center dot) radicals had a negligible contribution in the photodegradation of RhB. {001} BiOCl NS has shown a higher photocurrent density and lower charge transfer resistance analyzed through photoelectrochemical and electrochemical impedance measurements. This study highlights the fabrication of unique octagonal BiOCl NS with improved separation of charge carriers across high energy crystal facts to design a highly efficient photocatalyst.</P>
Haider, Zeeshan,Kang, Young Soo American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.13
<P>Owing to unique features, hierarchical nanostructure of TiO2 has superior photocatalytic activity. In this work a facile hydrothermal route has been explored to prepare 3D hierarchical TiO2 (3D-HTiO2), 1D/3D hybrid hierarchical TiO2 composite (HHC), and 3D hierarchical protonated titanate microspheres H2Ti2O5H2O (3DHPTMS) at the expense of free-standing titania nanotube membrane (TiO2-Memb). It proceeded through the formation of peroxotitanium complex, a water-soluble Ti complex as an intermediate. Mechanism of formation, role of membrane crystallinity, and reaction parameters giving fine control on tuning morphology and crystal structure have been investigated systematically. Photocatalytic activities were determined by measuring the amount hydrogen generated from water splitting under UV irradiation in the presence of methanol as a sacrificial reagent. Self-assembled hierarchical titania nanostructures exhibited much superior photocatalytic activity compared to that of starting material, i.e., TiO2-Memb. Enhanced photocatalytic activity is due to characteristic morphology, increased surface area, and enhanced production of photogenerated charge carriers.</P>
Zheng, Jin You,Song, Guang,Hong, Jisang,Van, Thanh Khue,Pawar, Amol Uttam,Kim, Do Yoon,Kim, Chang Woo,Haider, Zeeshan,Kang, Young Soo American Chemical Society 2014 Crystal Growth & Design Vol.14 No.11
<P>Single crystalline orthorhombic phase tungsten trioxide monohydrate (<I>O</I>-WO<SUB>3</SUB>·H<SUB>2</SUB>O, space group: <I>Pmnb</I>) nanoplates with a clear morphology and uniform size distribution have been synthesized by the hydrothermal method and fabricated on the surface of fluorine doped tin oxide (FTO) coated glass substrates with selective exposure of the crystal facet by the finger rubbing method. The rubbing method can easily arrange the <I>O</I>-WO<SUB>3</SUB>·H<SUB>2</SUB>O nanoplates along the (020) facet on the FTO substrate. The <I>O</I>-WO<SUB>3</SUB>·H<SUB>2</SUB>O nanoplate can be converted to monoclinic phase WO<SUB>3</SUB> (γ-WO<SUB>3</SUB>, space group: <I>P</I>21/<I>n</I>) with dominant crystal facet of (002) without destroying the plate structure. Crystal morphologies, structures, and components of the powders and films have been determined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, X-ray photoelectron spectroscopy, etc. The band gap energies of the <I>O</I>-WO<SUB>3</SUB>·H<SUB>2</SUB>O and γ-WO<SUB>3</SUB> nanoplates were determined as ca. 2.26 and 2.49 eV, respectively. Photoelectrochemical properties of the films with (002) dominant crystal facet have also been checked for discussion of further application in water oxidation. The advantage of (002) facet dominant film was investigated by comparing to one spin-coated γ-WO<SUB>3</SUB> thin film with the same thickness via photoelectrochemical characterizations such as photocurrent, incident photon to current efficiency, and electrochemical impedance spectroscopy.</P><P>Single crystalline orthorhombic phase <I>O</I>-WO<SUB>3</SUB>·H<SUB>2</SUB>O nanoplates with clear morphology and uniform size distribution have been synthesized by the hydrothermal method and fabricated as (020)-oriented film by the finger rubbing method. The (020)-oriented <I>O</I>-WO<SUB>3</SUB>·H<SUB>2</SUB>O film can be converted to monoclinic phase (002)-oriented γ-WO<SUB>3</SUB> film by calcination. Photoelectrochemical properties have been examined for further application in solar water oxidation.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cgdefu/2014/cgdefu.2014.14.issue-11/cg5012154/production/images/medium/cg-2014-012154_0016.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cg5012154'>ACS Electronic Supporting Info</A></P>