Hokkaido University · 화학공학
Shohei Tada 교수의 연구실은 CO2를 메탄올이나 메탄으로 효율적으로 전환하는 촉매 반응에 초점을 맞추고 있으며, 특히 Cu/ZrO2, Ni/CeO2, Zn-ZrO2 계 촉매의 표면 구조와 활성 사이트의 기원을 원자 수준에서 규명하는 데 기여하고 있습니다. 다양한 ZrO2 상태(아모르피스, 테트라고날, 모노클리닉)와 도핑 원소(Zn, Cu 등)의 조합이 촉매 성능에 미치는 영향을 실험과 계산을 융합해 연구하고 있습니다. 특히 촉매의 표면에 형성된 혼합 산화물 상과 산소 공여체(산소빈도)의 역할을 중심으로 반응 메커니즘을 해명하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
We examined the formation mechanism of active sites on Cu/ZrO2 specific toward CO2-to-methanol hydrogenation. The active sites on Cu/a-ZrO2 (a-: amorphous) were more suitable for CO2-to-methanol hydrogenation than those on Cu/t-ZrO2 (t-: tetragonal) and Cu/m-ZrO2 (m-: monoclinic). When a-ZrO2 was impregnated with a Cu(NO3)2·3H2O solution and then calcined under air, most of the Cu species entered a-ZrO2, leading to the formation of a Cu–Zr mixed oxide (CuaZr1-aOb). The H2 reduction of the thus-f
As for selective CO methanation over heterogeneous catalysts, numerous investigations of the reaction mechanism and catalyst development are reviewed.
We prepared Cu/a-ZrO2 (a-ZrO2: amorphous ZrO2), Cu/m-ZrO2 (m-ZrO2: monoclinic ZrO2), Cu/a-ZrO2/KIT-6, and Cu/t-ZrO2/KIT-6 (t-ZrO2: tetragonal ZrO2) by a simple impregnation method and examined the effect of the ZrO2 phase on CO2-to-methanol hydrogenation. We discovered a-ZrO2-containing catalysts with high activity and selectivity in CO2-to-methanol hydrogenation. Next, we focused on Cu species formation on the above-described catalysts. While pure CuO was observed on Cu/m-ZrO2 and Cu/t-ZrO2/KIT
We examined active sites for CO2 methanation over Ni/CeO2 catalysts prepared by a wet impregnation method. Four types of Ni/CeO2 with Ni loadings of 1, 3, 5, and 10 wt % were used in this study, assuming that the Ni sites are well dispersed in the catalysts when changing the Ni loading. According to powder X-ray diffraction and scanning transmission electron microscopy, the low-loading catalysts (1 and 3 wt %) consist mainly of Ni–Ce mixed oxides. The results of temperature-programmed reduction
Recently, ZnxZr1–xO2–x catalysts have attracted attention as next-generation CO2-to-methanol hydrogenation catalysts. In this study, we examined the effect of the Zn content on CO2-to-methanol hydrogenation over ZnxZr1–xO2–x catalysts and determined the active-site structure through both calculations and experiments. When the Zn content was low, ZnxZr1–xO2–x contained Zn clusters (isolated [ZnOa] clusters and [ZnbOc] oligomers). The presence of clusters indicates the formation of Zn–O–Zr sites.
Transmission electron microscopy (TEM), CO pulse, and N2O pulse titration were applied to measuring Ni particle sizes on Ni/α-Al2O3 catalysts. It was clarified for the first time that the N2O pulse titration could estimate the size at titration temperature between 50 and 100 °C, which was confirmed by TEM observation. This agreement in the Ni particle sizes by N2O titration and TEM observation means that the Ni surface was fully covered with the monolayer of oxygen formed by N2O decomposition an
