Army Academy ROC, Department of General Education, Taoyuan, 32093 Taiwan, Republic of China.
Appl Spectrosc. 2014;68(2):238-44. doi: 10.1366/13-07042.
The water-gas shift (WGS) reaction has been studied by pulsing carbon monoxide (CO) into a steady-state water (H2O)-Ar flow over nickel(II) oxide-zinc oxide (NiO-ZnO) catalysts using in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) coupled with a mass spectrometer method using the pulse technique (in situ pulse DRIFTS-MS) for different flow rates (gas hourly space velocity [GHSV] of 24,000-72,000 h(-1)) and reaction temperatures (250-350 °C). The results obtained from the in situ pulse DRIFTS-MS revealed that there are two types of water adsorption bands on the surface of the catalyst: (i) molecular adsorption (infrared [IR] bands in the 2500-3600 cm(-1) range and at 1640 cm(-1)), and (ii) dissociative adsorption at 3700 cm(-1), where carboxyl bands are formed at 1461 and 1368 cm(-1) and the gas-phase CO is adsorbed at 2187 and 2111 cm(-1) on the surface of the catalyst. After using a GHSV = 24,000 h(-1) H2O/Ar flow, we probed the existence of two active intermediates via the formation of two hydrogen production peaks. The products of hydrogen gas (H2) and carbon dioxide (CO2) had two pathways: the redox process and the associative process via the intermediate of the carboxyl group. In situ pulse DRIFTS-MS proves to be an effective approach for studying the nature of adsorbed species on the catalyst surface and the nature of the reaction product.
水煤气变换（WGS）反应已通过在镍(II)氧化物-氧化锌（NiO-ZnO）催化剂上用脉冲一氧化碳（CO）脉冲进入稳态水（H2O）-Ar 流的方式进行了研究，使用原位漫反射红外傅里叶变换光谱（DRIFTS）结合脉冲技术的质谱仪方法（原位脉冲 DRIFTS-MS），用于不同的流速（气体时空速度[GHSV]为 24,000-72,000 h-1）和反应温度（250-350°C）。从原位脉冲 DRIFTS-MS 获得的结果表明，催化剂表面有两种类型的水吸附带：（i）分子吸附（在 2500-3600 cm-1 范围内和 1640 cm-1 处的红外[IR]带）和（ii）在 3700 cm-1 处的离解吸附，其中羧基带形成于 1461 和 1368 cm-1 处，气相 CO 吸附于催化剂表面的 2187 和 2111 cm-1 处。在用 GHSV = 24,000 h-1 的 H2O/Ar 流处理后，我们通过形成两个制氢峰来探测两种活性中间体的存在。氢气（H2）和二氧化碳（CO2）产物有两条途径：通过羧基中间产物的氧化还原过程和缔合过程。原位脉冲 DRIFTS-MS 被证明是研究催化剂表面吸附物种的性质和反应产物的性质的有效方法。
