Pd/N-C催化剂的制备及其催化脱氢偶联反应

Preparation of nitrogen-doped carbon supported Pd catalyst for the catalytic dehydrogenative coupling reaction

摘要:

使用葡萄糖为碳源，硫脲为氮源合成了氮掺杂碳载体（N-C），再利用掺杂的氮原子作为作用位点，与贵金属钯纳米粒子（Pd NPs）相互作用，得到N-C负载Pd纳米粒子（Pd/N-C）催化剂，并用于硅烷与醇的脱氢偶联反应。使用XRD、XPS、SEM、TEM、ICP-OES和GC-MS对催化剂进行结构和性能表征，表征结果表明负载在载体上的Pd NPs分散均匀，粒径大小为（4.87±1.10） nm；Pd/N-C中的N与Pd NPs相互作用能有效分散并稳定Pd NPs。与Pd/C催化剂对比，N-C载体对Pd催化剂的催化性能具有显著的促进作用，Pd/N-C催化剂催化二苯基硅烷与甲醇的脱氢偶联反应1h的二苯基硅烷转化率和二苯基二甲氧基硅烷的选择性均可达到99%以上，循环实验表明其循环6次后仍能保持反应物转化率92%以上，最终产物二苯基二甲氧基硅烷选择达到99%以上。不同硅烷及醇底物拓展实验表明Pd/N-C催化剂具有良好催化效果和底物普适性。

Abstract:

Nitrogen-doped carbon support (N-C) was synthesized using glucose as a carbon source and thiourea as a nitrogen source. The doped nitrogen atoms were then used as active sites to interact with palladium nanoparticles (Pd NPs), resulting in Pd/N-C catalyst. This catalyst was then employed for the dehydrogenative coupling reaction of silane with alcohol. The catalyst was characterized using XRD, XPS, SEM, TEM, ICP-OES, and GC-MS. The characterization results indicated that the Pd NPs were uniformly dispersed on the support with a particle size of (4.87±1.10) nm. The interaction between N in the N-C support and Pd NPs effectively dispersed and stabilized the Pd NPs. Compared to the Pd/C catalyst, the N-C support exhibited a significant promotional effect on the catalytic performance of the Pd catalyst. The Pd/N-C catalyst achieved a diphenylsilane conversion and diphenyldimethoxysilane selectivity of over 99% after 1 h for the dehydrogenative coupling reaction of diphenylsilane with methanol. Cycling experiments demonstrated that the catalyst retained a conversion rate of over 92% after six cycles, and the final product, diphenyldimethoxysilane, achieved a selectivity of over 99%. Experiments with different silane and alcohol substrates showed that the Pd/N-C catalyst exhibited excellent catalytic performance and substrate versatility.