Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1016/j.ijhydene.2023.04.263

Authorship：Last author   Publishing type：Research paper (scientific journal)   International / domestic magazine：International journal  

DOI： 10.1021/acs.jpcc.2c09084

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

DOI： 10.1039/d2ma00904h

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Intermetallic or substitutional solid-solution PdZn alloy nanoparticle (NP)-loaded carbon black (i-PdZn/C, s-PdZn/C) was prepared by reducing equimolar palladium acetate and zinc acetate in ethanol dispersion of carbon black with sodium tetrahydroborate with and without the following heat-treatment in an autoclave. The Pd 3d and Zn 2p core-level spectra exhibited that the binding energy of Pd and Zn for i-PdZn/C shifted positively and negatively compared to that for metallic Pd and Zn sheets, respectively, suggesting a strong electronic interaction between Pd and Zn. In contrast, for s-PdZn/C, the binding energy for Pd shifted positively, but only a peak for ZnO was observed. In 1 M KOH aqueous solution at 20 oC, the Zn content of s-PdZn/C was almost zero in 30 min, while i-PdZn/C held the Zn component of 75% at 20 oC and 70% at 60 oC after 30 min, indicating that i-PdZn/C was much more tolerant to alkaline medium than s-PdZn/C. Consequently, s-PdZn NPs were changed to porous Pd NPs, whereas i-PdZn NPs were changed to core-shell NPs whose surface was porous Pd. In the (1 M KOH + 1 M ethanol) aqueous solution at 20 oC, i-PdZn/C and s-PdZn/C significantly enhanced the activity for ethanol oxidation reaction (EOR) compared to Pd NP-loaded carbon black (Pd/C). In the potentiostatic electrolysis at 0.7 V for 10,000 s, the deterioration of i-PdZn/C was effectively delayed compared to Pd/C and s-PdZn/C due to the electronic effect of the intermetallic PdZn core.

DOI： 10.1007/s11164-022-04780-z

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Exploring simple and flexible methods to synthesize an oxygen reduction reaction (ORR) catalyst with high catalytic activity is of great significance for the large-scale application of fuel cells. Here we developed an intermetallic PdZn on a TiO2-x NS support catalyst by a simple strategy for large-scale production through an impregnation process involving low temperature annealing. This electrocatalyst prepared by a simple and single step exhibited better ORR activities in both acidic and alkaline solutions at room temperature with a higher value of electrochemical active surface area (ECSA). The repeated square-wave potential cycling test at 80 degrees C over 10 000 cycles confirmed the durability of the catalyst. The fuel cell using the PdZn/TiO2-x NS catalyst showed a high power density of 855 mW cm(-2), which exceeds that of the PdZn supported carbon catalyst. Also, the proposed catalyst showed excellent stability over more than 100 h in proton-exchange membrane fuel cell (PEMFC) performance. Thus, the proposed TiO2-x NSs will be an alternative to a carbon support in future PEMFC technology. Furthermore, PdZn/TiO2-x NSs also showed higher activity and stability for the glycerol oxidation reaction (GOR) and higher selectivity for glycerate production than PdZn/C. Hence, the PdZn/TiO2-x NS electrocatalyst opens up new avenues towards energy conversion devices such as DAFCs and metal-air batteries. This new study provides an opportunity for further research to rationally design more carbon free supported nanostructured intermetallics by using different transition metals for efficient electrochemical energy storage devices.

DOI： 10.1039/d2ta03736j

Authorship：Last author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

The increase in mechanical stress at the interface of the Li metal and solid electrolyte induces dendritic Li growth in all-solid-state Li batteries. We demonstrated the increasing stress in Li metal was significantly reduced by porous current collectors (PCCs). Here, we demonstrate the PCC with 3- dimensional pores prepared by sintering a mixture of micrometer-sized Ni spherical particles and polymethyl methacrylate spheres as a template of pores. The low-cost sintering method realized not only reduction of the preparation cost of PCCs, but high internal short circuit resistance comparable to the expensive PCCs with regularly arranged through-holes using electroforming methods.

DOI： 10.1149/1945-7111/ac62c0

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Pt/Rh bimetal catalysts are often used in various reactions such as alcohol oxidation and hydrogenation. For comparison, their catalytic activity is often standardized by the real surface area or electrochemical surface area. However, the conventional method of using the electric charge for hydrogen desorption is difficult to apply to Pt/Rh bimetal catalysts because the potential regions of hydrogen desorption for Pt and Rh overlap. In this study, Rh-adlayer-modified Pt (Rh-x/Pt) electrodes with different Rh coverages were prepared by underpotential depositions of Cu adatoms at different potentials followed by galvanic replacement of Cu with rhodium, and CO stripping was applied to determine the Rh coverages of these electrodes. No CO that had been adsorbed on a Pt electrode was removed by potentiostatic CO oxidation at 0.75 V vs reversible hydrogen electrode for 15 s in an Ar-saturated 0.5 M sulfuric acid solution at 5 degrees C, but 85% of CO on an Rh electrode was removed. The Rh coverages for the Rh-x/Pt electrodes corrected on the basis of this result were in good agreement with the corresponding Rh coverages estimated from the electric charge for the stripping of the Cu adlayer. Moreover, the Rh-x/Pt electrodes exhibited noteworthy CO-stripping and CO-adsorption behaviors. A single CO-stripping cyclic voltammetry peak was observed regardless of Rh coverage, and shifted toward lower potential as the Rh coverage was increased. This result resembled the trend of initiation potentials of chemisorbed oxygen formation, suggesting a bifunctional mechanism. In infrared reflectance-absorption spectra of the CO-adsorbed Rh-x/Pt electrodes, a single asymmetric band assigned to "atop" CO was observed irrespective of the Rh coverage, and shifted to lower wavenumbers as the Rh coverage was increased. The d-band center estimated from the valence level spectra of the Rh-x/Pt electrodes, which reflected the Pt 5d electronic structure, shifted downward as the Rh coverage was increased.

DOI： 10.1021/acs.jpcc.1c02039

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

A couple of toluene (TL) and its hydrogenation product, methylcyclohexane (MCH), are promising high-density hydrogen carriers to store and transport large amounts of hydrogen. Electrochemical hydrogenation of TL to MCH can achieve energy savings compared with hydrogenation using molecular hydrogen generated separately, and development of highly active catalysts for electrochemical TL hydrogenation is indispensable. In this study, binary Pt3M (M = Rh, Au, Pd, Ir, Cu and Ni) alloy nanoparticle-loaded carbon catalysts were prepared by a colloidal method, and their activity for electrochemical TL hydrogenation was evaluated by linear sweep voltammetry. Each Pt3M electrode was initially activated by 100 cycles of potential sweep over a potential range of 0-1.2 or 0.8 V vs. reversible hydrogen electrode (RHE). For all activated Pt3M electrodes, the cathodic current density for electrochemical TL hydrogenation was observed above 0 V, that is the standard potential of hydrogen evolution reaction. Both specific activity, cathodic current density per electrochemical surface area, and mass activity, cathodic current density per mass of Pt3M, at 0 V for the Pt3Rh/C electrode were the highest, and about 8- and 1.2-times as high as those of the commercial Pt/C electrode, respectively, which could mainly be attributed to electronic modification of Pt by alloying with Rh. The Tafel slope for each activated Pt3M/C electrode exhibited the alloying of Pt with the second metals did not change the electrochemical TL hydrogenation mechanism.

DOI： 10.3390/catal11030318

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Authorship：Last author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Developing novel hydrogen evolution reaction (HER) catalysts with high activity, high stability and low cost is of great importance for the ever-broader applications of hydrogen energy. Among the conventionally used platinum-based heterogeneous catalysts, the high consumption and low utilization efficiency of precious platinum are the most crucial issues. Herein we present a facile approach to prepare an effective HER catalyst with platinum nanoparticles dispersed on oxygen-deficient TiO(2-x)nanosheets (NSs). The fabricated Pt-TiO2-xNS electrocatalyst shows an overpotential of 35 mV at 10 mA cm(-2)for the HER in 0.5 M H2SO4, which is highly comparable to that of commercial Pt/C (34 mV). More attractively, the Pt-TiO2-xNS electrocatalyst largely enhanced the mass activity (MA) of Pt and electrochemical stability compared to commercial Pt/C. The excellent HER performance of Pt-TiO(2-x)NSs is attributed to the synergetic effect between highly dispersed Pt species and TiO(2-x)NSs with oxygen vacancies, which enhances both electrocatalytic activity and durability over a wide pH range. This strategy can provide insights into constructing highly efficient catalysts and their support for different energy-related applications.

DOI： 10.1039/d0nr02092c

Authorship：Last author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

The activity and stability for oxygen reduction reaction (ORR) of the cathode catalyst of proton exchange membrane fuel cells (PEMFCs) are important issues that should even be considered for practical application. Modifying the catalyst electronic structure and finding durable supports are good approaches for improving these properties. Carbon-free multifunctional oxygen-deficient titanium oxide nanosheets (TiO2-x NSs) are established as a catalyst support for fuel cell application. The TiO2-x NSs support shows improved electronic conduction compared to TiO2 NSs. Pt nanoparticle-loaded TiO2-x NSs (Pt-TiO2-x, NSs) catalyst prepared in this study shows excellent activity towards the ORR. This is ascribed to a strong metal-support interaction (SMSI) between the Pt nanoparticles (NPs) and the TiO2-x NSs support. In addition, the TiO2-x NSs catalyst shows outstanding durability in repeating square-wave potential cycling tests at 80 degrees C over 10000 cycles. The fuel cell using the Pt-TiO2-x NSs catalyst shows high power density (958 mWcm(-2)), which exceeds that of the commercial Ptloaded carbon catalyst. Also, the projected catalyst showed an excellent stability (more than 100 h) in fuel cell performance. Thus, the proposed TiO2-x NSs will be a promising carbon-free support to be loaded in the future PEMFCs technology.

DOI： 10.1016/j.jpowsour.2020.227972

Authorship：Last author   Publishing type：Research paper (scientific journal)   Kind of work：Joint Work   International / domestic magazine：International journal  

Copper chloride (CuCl2) was investigated for the first time as conversion-type positive electrode material in a rechargeable Al battery. The electrode was reversibly charged and discharged in an electrolyte solution of AlCl3, dipropylsulfone, and toluene (1 : 10 : 5 molar ratio). The initial discharge capacity was about 370 mA h (g-CuCl2)(-1) at 0.028C-rate (11 mA (g-CuCl2)(-1)), which was almost the same as the theoretical value (399 mA h (g-CuCl2)(-1)) and higher than that of insertion-type positive electrode materials as used in the rechargeable Al battery. Moreover, a two-stage discharge plateau voltage was observed at 1.5 V and 0.8 V, which was higher than other conversion type positive electrodes for the aluminum rechargeable battery. The high discharge voltage realized a high energy density of 426 mW h (g-CuCl2)(-1), which is the highest energy density compared with other conversion type positive electrodes. Two different strategies were implemented to increase the lifetime of the cell, namely, increasing the upper cut-off voltage and decreasing the particle size of CuCl2. The discharge capacity for the electrode at the second cycle was threefold that for a pristine CuCl2 electrode.

DOI： 10.1039/c9ra09158k

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Presentation type：Poster presentation  

Venue：Tendo  

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Venue：大阪  

Presentation type：Oral presentation (general)  

Venue：大阪  

Presentation type：Poster presentation  

Venue：鎌倉  

Presentation type：Poster presentation  

Venue：大阪  

Presentation type：Poster presentation  

Venue：大阪  

Presentation type：Oral presentation (general)  

Venue：福岡  

Presentation type：Poster presentation  

Venue：姫路  

Presentation type：Oral presentation (general)  

Venue：横浜  

Presentation type：Oral presentation (general)  

Venue：仙台  

Presentation type：Poster presentation  

Venue：Singapore  

Presentation type：Poster presentation  

Venue：オンライン  

Presentation type：Poster presentation  

Venue：大阪  

Presentation type：Oral presentation (general)  

Venue：大分  

Presentation type：Oral presentation (general)  

Venue：福岡  

Presentation type：Poster presentation  

Venue：船橋  

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：立命館大学東京キャンパス  

Presentation type：Oral presentation (general)  

Venue：神奈川大学  

Presentation type：Oral presentation (general)  

Venue：オンライン