功能化氮化碳对Pd基甲酸分解制氢催化剂性能的促进作用

负载型Pd基催化剂是最有效的甲酸分解(FAD)制氢催化剂之一,其中氮化碳载体的N含量较高,但是通常一步热解法制备的氮化碳为块状,难以有效分散表面金属纳米粒子(NPs)。 本文通过将尿素前驱体在溶剂化作用后热解得到功能化氮化碳,以此为载体,利用阴离子交换和硼氢化钠直接还原法制备了功能化氮化碳负载的Pd基催化剂(Pd/C₃N₄-F)。 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)对材料结构进行表征,并通过气体质量流量计测试了催化剂的性能。 Pd/C₃N₄-F具有优异的催化FAD制氢性能,30 ℃下的初始TOF(总转换频率)值和质量比活性分别为1824 h^-1和17.14 mol_H2/(g_Pd·h)。 对产物的气相色谱分析结果也表明没有副产物CO生成,表明催化剂具有优异的选择性。 并且随着温度的升高(30～40 ℃),催化剂性能逐渐提高。

Promotion Effect of Functionalized Carbon Nitride on Pd-Based Catalyst for Hydrogen Generation from Formic Acid

The supported Pd-based catalyst is one of the most effective catalysts for the decomposition of formic acid into hydrogen, in which the N content of the carbon nitride support is relatively high. The carbon nitride prepared by one-step pyrolysis method is usually bulk, which makes it difficult to effectively disperse surface metal nanoparticles (NPs). Functionalized carbon nitride was obtained by pyrolyzing the urea precursor after solvation and used as a support. A functional carbon nitride-supported Pd-based catalyst (Pd/C₃N₄-F) was prepared by anion exchange and sodium borohydride direct reduction. The structure of the material was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS), and the performance of the catalyst was tested by gas mass flow meter. Pd/C₃N₄-F has excellent catalytic performance for hydrogen production from formic acid decomposition and its initial TOF (total conversion frequency) value and mass specific activity at 30 ℃ are 1824 h^-1 and 17.14 mol_H2/(g_Pd·h), respectively. The analysis of the product by gas chromatography (GS) shows that no by-product CO is formed, indicating that it has excellent selectivity. With the increase of temperature (30~40 ℃), the catalyst performance gradually improves