Selective reduction of benzaldehyde to benzyl alcohol (model reaction for low-temperature stabilization of bio-oil) on C-supported Pt, Rh, Pd, and Ni in aqueous phase was conducted using either H₂ (thermal catalytic hydrogenation, TCH) or hydrogen generated in situ electrocatalytically (electrocatalytic hydrogenation, ECH). In TCH, the intrinsic activity of the metals at room temperature and 1 bar H₂ increased in the sequence Pt/C < Rh/C ≤ Pd/C, while Ni/C is inactive. At these conditions, the coverage of benzaldehyde is high while the coverage of adsorbed H is low and the reaction follows a Langmuir-Hinshelwood mechanism. All tested metals were active in ECH of benzaldehyde above the onset potentials of the H₂ evolution reaction (HER). Thus, hydrogenation competes with HER. The relative rates of H reacting to H₂ and H addition to benzaldehyde determines the selectivity to ECH and HER. Accordingly, the selectivity of the metals towards ECH increases in the order as follows: Ni/C < Pt/C < Rh/C < Pd/C. The latter having ECH selectivity around 99%. In ECH, the intrinsic activities of all tested metals were higher and the activation energies of benzaldehyde hydrogenation were lower than in TCH.

使用H ₂（热催化加氢，TCH）或氢气将苯甲醛选择性还原为C负载的Pt，Rh，Pd和Ni上的苯甲醇（生物油的低温稳定模型反应）。电催化原位生成（电催化加氢，ECH）。在TCH中，金属在室温和1 bar H ₂下的固有活性按Pt / C <Rh / C≤Pd / C的顺序增加，而Ni / C则无活性。在这些条件下，苯甲醛的覆盖率较高，而吸附的H的覆盖率较低，反应遵循Langmuir-Hinshelwood机理。在H ₂的起始电位以上，所有测试的金属在苯甲醛的ECH中均具有活性。进化反应（HER）。因此，氢化与HER竞争。H与H ₂反应和H加至苯甲醛的相对速率决定了对ECH和HER的选择性。因此，金属对ECH的选择性按以下顺序增加：Ni / C ＜Pt / C ＜Rh / C ＜Pd / C。后者的ECH选择性约为99％。在ECH中，与TCH中相比，所有测试金属的固有活性都较高，苯甲醛加氢的活化能较低。