Cu Species Incorporated into Amorphous ZrO2 with High Activity and Selectivity in CO2-to-Methanol Hydrogenation
Cu Species Incorporated into Amorphous ZrO2 with High Activity and Selectivity in CO2-to-Methanol Hydrogenation
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DOI：
10.1021/acs.jpcc.7b11284
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发表时间：
2018-03-15
影响因子：
3.7
通讯作者：
Satokawa, Shigeo
中科院分区：
文献类型：
--
作者：
Tada, Shohei;Katagiri, Ayaka;Satokawa, Shigeo
采用简单浸渍法制备了Cu/a-ZrO2 （a-ZrO2：无定形ZrO2）、Cu/m-ZrO2 （m-ZrO2：单斜形ZrO2）、Cu/a-ZrO2/KIT-6和Cu/t-ZrO2/KIT-6 (t-ZrO2：四边形ZrO2)，并考察了ZrO2相对co2加氢制甲醇的影响。我们发现了含有a- zro2的催化剂，在co2加氢制甲醇过程中具有较高的活性和选择性。接下来，我们重点研究了上述催化剂上Cu物种的形成。在Cu/m-ZrO2和Cu/t-ZrO2/KIT-6表面可以观察到纯CuO，而在Cu/a-ZrO2和Cu/a-ZrO2/KIT-6表面形成的不是纯CuO，而是铜锆混合氧化物（CuxZryOz），这可以通过x射线吸收光谱（XAS）和粉末颜色来证明。在300℃下用H-2还原含a-ZrO2的催化剂后，我们观察到高度分散的Cu纳米颗粒与a-ZrO2（或CuxZryOz）紧密接触。甲醇水蒸气吸附结果表明，甲醇对a-ZrO2的吸附比对m-ZrO2的吸附弱。因此，Cu的高度分散和甲醇的弱吸附使得co2加氢具有较高的活性和选择性。
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-6, copper-zirconium mixed oxide (CuxZryOz), not pure CuO, was formed on Cu/a-ZrO2 and Cu/a-ZrO2/KIT-6, as evidenced by X-ray absorption spectroscopy (XAS) and the powder color. After reducing a-ZrO2-containing catalysts with H-2 at 300 degrees C, we observed highly dispersed Cu nanoparticles in close contact with a-ZrO2 (or CuxZryOz). In addition, methanol vapor sorption revealed that methanol adsorbed more weakly on a-ZrO2 than on m-ZrO2. Therefore, the high dispersion of Cu species and weak adsorption of methanol led to high activity and selectivity in CO2-to-methanol hydrogenation.