Pd based bimetallic catalysts, Pd-M, (M=Cu, Ag, and Au) supported on TiO2 P-25, have been prepared by chemical reduction with glucose and characterized by XRD, TEM, XPS, DRS, TPR and H2TPD. Activity for the conversion of cinnamaldehyde (CAL) and selectivity to hydro-cinnamaldehyde (HCAL), cinnamyl alcohol (COL) and hydrocinnamyl alcohol (HCOL) have been evaluated in the temperature range of 120-140 °C for 1 h and 10 bar hydrogen pressure. For comparison, monometallic Cu, Ag and Au (1% w/w in each case) catalysts supported on TiO2 P-25 have been prepared and evaluated. DRS and XPS studies reveal nanoscale alloy formation and re-distribution of charges in bimetallic catalysts. Bimetallic Pd-Cu displays higher CAL conversion compared to Pd-Ag and Pd-Au. Besides the favourable electronic and ensemble effects, availability of reactive hydrogen on Pd-Cu, as revealed by the lowest hydrogen desorption temperature, is an additional factor that contributes towards the higher activity of Pd-Cu. Bimetallic catalysts are stable up to five reaction cycles, without any loss of Pd or structural integrity.

中文翻译：

---

使用钯基双金属催化剂 Pd-M/TiO2（M=Cu、Ag 和 Au）选择性加氢肉桂醛

负载在 TiO2 P-25 上的 Pd 基双金属催化剂 Pd-M（M=Cu、Ag 和 Au）已通过葡萄糖化学还原制备，并通过 XRD、TEM、XPS、DRS、TPR 和 H2TPD 进行表征。肉桂醛 (CAL) 的转化活性和对氢化肉桂醛 (HCAL)、肉桂醇 (COL) 和氢化肉桂醇 (HCOL) 的选择性已在 120-140 °C 的温度范围内进行了 1 小时和 10 巴氢气的评估压力。为了比较，制备并评估了负载在 TiO2 P-25 上的单金属 Cu、Ag 和 Au（在每种情况下均为 1% w/w）催化剂。DRS 和 XPS 研究揭示了双金属催化剂中纳米级合金的形成和电荷的重新分布。与 Pd-Ag 和 Pd-Au 相比，双金属 Pd-Cu 显示出更高的 CAL 转化率。除了有利的电子和整体效应，Pd-Cu 上活性氢的可用性，正如最低的氢解吸温度所揭示的那样，是有助于提高 Pd-Cu 活性的附加因素。双金属催化剂在五个反应周期内保持稳定，不会损失 Pd 或结构完整性。